# MapTools — Full Public Content Export

> Machine-readable plain-text export of public MapTools content: product
> descriptions and map-reading guidance (coordinate systems, declination,
> UTM/MGRS/USNG, plotting). Generated 2026-09-06. Canonical site: https://maptools.com/.
> No customer, order, or back-office data is included.

## Products

### 1:10,000 Scale Nautical Map Ruler
https://maptools.com/product/Ruler10N

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or nautical miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody> <tr> <td>1:10,000</td> <td><ul> <li>NOAA Marine charts</li> </ul></td> <td>0.5 min</td> <td>0.01 min</td> <td>1 sec</td> <td>10 m</td> <td>0.01 nm</td> </tr> </tbody></table>

### 1:100,000 Scale Map Ruler
https://maptools.com/product/Ruler100

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:100,000</td> <td><ul> <li>USGS &amp; BLM 30 X 60 minute topographic maps</li> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Delaware</li> <li>Maryland</li> <li>New Hampshire</li> <li>Vermont</li> </ul> </ul></td> <td>10 min</td> <td>0.05 min</td> <td>5 sec</td> <td>50 m</td> <td>0.05 mi</td> </tr> </tbody></table>

### 1:100,000 Scale Nautical Map Ruler
https://maptools.com/product/Ruler100N

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or nautical miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:100,000</td> <td><ul> <li>NOAA Marine charts</li> </ul></td> <td>10 min</td> <td>0.05 min</td> <td>5 sec</td> <td>50 m</td> <td>0.1 nm</td> </tr> </tbody></table>

### 1:100,000 Scale UTM Grid — For 1° X 2° USGS & BLM Maps
https://maptools.com/product/UTMGrid100

This easy to use grid tool divides a 10 kilometer grid square into 1 kilometer squares. Align the tool on the map grid and read off the easting and northing (sku,version,type,description) VALUES. Additionally, by using a straight edge and the 100m tics along the edge, it is possible to locate a point with 100m precision.<br /><br /> The tool is about the thickness of a credit card, and the ink is coated to protect it from abrasion.

### 1:12,000 & 1:24,000 Slot Tool — Fast and easy UTM plotting
https://maptools.com/product/UTMSlot12

This tool enables you to plot UTM coordinates to a 10 meter accuracy within a 1 kilometer grid square. The tool also has a compass rose along its outside edge. This makes plotting or measuring a bearing a snap. The small size of this tool will allow you to keep it handy in your pocket. A band of white ink around the edge of the tool makes reading the compass rose easier and also keeps the tool from "disappearing" when you place it on the map. There is also a lanyard hole in the upper left corner.<br /><br /> Printed on plastic stock, the tool is about the thickness of a credit card.

### 1:125,000 Scale Map Ruler
https://maptools.com/product/Ruler125

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody> <tr> <td>1:125,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Maine (Old editions. New editions are 1:135,000)</li> </ul> </ul></td> <td>7.5 min</td> <td>0.05 min</td> <td>5 sec</td> <td>50 m</td> <td>0.1 mi</td> </tr> </tbody></table>

### 1:126,720 Scale Map Ruler
https://maptools.com/product/Ruler126

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:126,720</td> <td><ul> <li>US Forest Service forest maps</li> <li>1/2 inch = 1 mile maps</li> </ul></td> <td>7.5 min</td> <td>0.05 min</td> <td>5 sec</td> <td>50 m</td> <td>0.1 mi</td> </tr> </tbody></table>

### 1:15,000 Scale Nautical Map Ruler
https://maptools.com/product/Ruler15N

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or nautical miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:15,000</td> <td><ul> <li>NOAA Marine charts</li> </ul></td> <td>1 min</td> <td>0.01 min</td> <td>1 sec</td> <td>10 m</td> <td>0.01 nm</td> </tr> </tbody></table>

### 1:150,000 Scale Map Ruler
https://maptools.com/product/Ruler150

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody> <tr> <td>1:150,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>California</li> <li>Florida</li> <li>Illinois</li> <li>Kentucky</li> <li>Michigan</li> <li>New York</li> <li>North Carolina</li> <li>Ohio</li> <li>Oklahoma</li> <li>Oregon</li> <li>Pennsylvania</li> <li>South Carolina</li> <li>Tennessee</li> <li>Virginia</li> <li>Washington</li> <li>West Virginia</li> <li>Wisconsin</li> </ul> </ul></td> <td>15 min</td> <td>0.1 min</td> <td>5 sec</td> <td>100 m</td> <td>0.1 mi</td> </tr> </tbody></table>

### 1:156,000 Scale Map Ruler
https://maptools.com/product/Ruler156

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:156,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Indiana</li> </ul> </ul></td> <td>15 min</td> <td>0.05 min</td> <td>5 sec</td> <td>100 m</td> <td>0.1 mi</td> </tr> </tbody></table>

### 1:160,000 Scale Map Ruler
https://maptools.com/product/Ruler160

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:160,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Colorado</li> </ul> </ul></td> <td>15 min</td> <td>0.05 min</td> <td>5 sec</td> <td>100 m</td> <td>0.1 mi</td> </tr> </tbody></table>

### 1:182,000 Scale Map Ruler
https://maptools.com/product/Ruler182

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:182,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Georgia</li> <li>Louisiana</li> <li>Mississippi</li> </ul> </ul></td> <td>15 min</td> <td>0.1 min</td> <td>5 sec</td> <td>100 m</td> <td>0.1 mi</td> </tr> </tbody></table>

### 1:190,000 Scale Map Ruler
https://maptools.com/product/Ruler190

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:190,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Minnesota (Old editions. New editions are 1:205,000) </li> </ul> </ul></td> <td>15 min</td> <td>0.1 min</td> <td>5 sec</td> <td>100 m</td> <td>0.1 mi</td> </tr> </tbody></table>

### 1:20,000 Scale Nautical Map Ruler
https://maptools.com/product/Ruler20N

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or nautical miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:20,000</td> <td><ul> <li>NOAA Marine charts</li> <li>British Columbia TRIM Maps (Terrain Resource Information Management)</li> </ul></td> <td>1 min</td> <td>0.01 min</td> <td>1 sec</td> <td>10 m</td> <td>0.01 nm</td> </tr> </tbody></table>

### 1:200,000 Scale Map Ruler
https://maptools.com/product/Ruler200

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:200,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Alabama</li> <li>Arkansas</li> <li>Iowa</li> <li>Kansas</li> <li>Missouri</li> <li>Nebraska</li> <li>North Dakota</li> <li>South Dakota</li> </ul> </ul></td> <td>15 min</td> <td>0.1 min</td> <td>10 sec</td> <td>100 m</td> <td>0.1 mi</td> </tr> </tbody></table>

### 1:24,000 Credit Card Sized UTM Slot Tool — also includes distance in miles and feet
https://maptools.com/product/UTM-SC24

This tool enables you to plot UTM coordinates to a 10 meter accuracy within a 1 kilometer grid square. The tool includes 2 distance rulers; one mile divided into 0.01 mile increments, and 3700 feet divided into 100 foot increments. The small size of this tool will allow you to keep it handy in your pocket or wallet. A band of white ink around the edge of the tool makes reading the distance scales easier and also keeps the tool from “disappearing” when you place it on the map. There is also a badge slot to allow use with any standard sized badge clip. <br /><br /> Printed on plastic stock, the tool is about the thickness of a credit card. The ink is coated to protect it from abrasion.

### 1:24,000 Pocket Sized Slot Tool — Fast and easy UTM plotting
https://maptools.com/product/UTMSlot24

This tool enables you to plot UTM coordinates to a 10 meter accuracy within a 1 kilometer grid square. The tool also has a compass rose along its outside edge. This makes plotting or measuring a bearing a snap. The small size of this tool will allow you to keep it handy in your pocket. A band of white ink around the edge of the tool makes reading the compass rose easier and also keeps the tool from "disappearing" when you place it on the map. There is also a lanyard hole in the upper left corner.<br /><br /> Printed on plastic stock, the tool is about the thickness of a credit card. The ink is coated to protect it from abrasion.

### 1:24,000 Scale Map Ruler
https://maptools.com/product/Ruler24

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:24,000</td> <td><ul> <li>USGS 7.5 minute topographic maps</li> </ul></td> <td>2.5 min</td> <td>0.01 min</td> <td>1 sec</td> <td>10 m</td> <td>0.01 mi</td> </tr> </tbody></table>

### 1:24,000 Scale Pocket Size UTM Grid — Fast and easy UTM plotting
https://maptools.com/product/UTMGrid24

An easy-to-use grid tool that divides a 1-kilometer grid square into 100-meter squares. Align the tool on the map grid and read off the easting and northing values. The tool also has a compass rose protractor along the outside edge. This makes plotting or measuring a bearing a snap. The small size of the tool allows you to keep it handy in your pocket.<br /><br /> A band of white ink around the edge makes reading the compass rose and grid numbers easier and also keeps the tool from "disappearing" when you place it on the map. In the center of each 100m square, a small dot makes it easy to read the coordinate with a 50m precision. There is a lanyard hole in the upper left corner.<br /><br /> Printed on 30 mil plastic stock, the tools are about the thickness of a credit card. The ink is coated to protect it from abrasion.<br /><br />

### 1:24,000 Scale Slope Ruler — Estimate %slope or slope angle from contour lines
https://maptools.com/product/RulerSlope24

<p>This ruler is designed to measure slope on a 1:24,000 scale topographic map. Slope is determined by comparing the distance between contour lines with the samples on the edge of the ruler.</p> <p>The front side of the ruler is designed to measure percent slope for maps with a 10, 20 or 40 foot contour interval.</p> <p>The back side of the ruler measures slope in degrees for maps with a 20 or 40 foot contour interval. The back side also indicates slab avalanche frequency for the various slopes on the 40 foot contour interval map.</p> <p>If you need to physically measure a slope angle, check out our Reference Card -- Inclinometer for Slope Angle in Degrees and Percent.</p> <p>The ruler is printed on a sturdy 20 mil white plastic stock for durability.</p>

### 1:25,000 Credit Card Sized UTM Slot Tool — also includes distance in miles and feet
https://maptools.com/product/UTM-SC25

This tool enables you to plot UTM coordinates to a 10 meter accuracy within a 1 kilometer grid square. The tool includes 2 distance rulers; one mile divided into 0.01 mile increments, and 3700 feet divided into 100 foot increments. The small size of this tool will allow you to keep it handy in your pocket or wallet. A band of white ink around the edge of the tool makes reading the distance scales easier and also keeps the tool from “disappearing” when you place it on the map. There is also a badge slot to allow use with any standard sized badge clip. <br /><br /> Printed on plastic stock, the tool is about the thickness of a credit card. The ink is coated to protect it from abrasion.

### 1:25,000 Scale Map Ruler
https://maptools.com/product/Ruler25

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:25,000</td> <td><ul> <li>USGS 7.5 minute topographic maps of Alaska and a few places in the Continental United States</li> </ul></td> <td>2.5 min</td> <td>0.01 min</td> <td>1 sec</td> <td>10 m</td> <td>0.01 mi</td> </tr> </tbody></table>

### 1:25,000 Scale Pocket Size UTM Grid — Fast and easy UTM plotting
https://maptools.com/product/UTMGrid25

An easy to use grid tool that divides a 1 kilometer grid square into 100 meter squares. Align the tool on the map grid and read off the easting and northing (sku,version,type,description) VALUES. The tool also has a compass rose protractor along the outside edge. This makes plotting or measuring a bearing a snap. The small size of the tool allows you to keep it handy in your pocket.<br /><br /> A band of white ink around the edge makes reading the compass rose and grid numbers easier and also keeps the tool from "disappearing" when you place it on the map. In the center of each 100m square a small dot, makes it easy to read the coordinate with a 50m precision. There is a lanyard hole in the upper left corner.<br /><br /> Printed on 30 mil plastic stock the tools are about the thickness of a credit card. The ink is coated to protect it from abrasion.<br />

### 1:250,000 Scale Map Ruler
https://maptools.com/product/Ruler250

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:250,000</td> <td><ul> <li>USGS 1 X 2 degree series topographic maps</li> <li>Canadian National Topographic System (NTS) maps</li> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Arizona (Old editions. New edition is 1:260,000)</li> <li>Idaho</li> <li>Montana</li> <li>Nevada</li> <li>Utah (Old editions. New editions are 1:235,000)</li> <li>Wyoming (Old editions. New editions are 1:225,000)</li> </ul> </ul> <td>15 min</td> <td>0.1 min</td> <td>15 sec</td> <td>100 m</td> <td>0.1 mi</td> </tr> </tbody></table>

### 1:280,000 Scale Map Ruler
https://maptools.com/product/Ruler280

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><br /><tbody> <tr> <td>1:280,000</td> <td><ul> </ul> </ul></td> <td>20 min</td> <td>0.1 min</td> <td>10 sec</td> <td>100 m</td> <td>0.1 mi</td> </tr> </tbody></table>

### 1:30,000 Scale Nautical Map Ruler
https://maptools.com/product/Ruler30N

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or nautical miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody> <tr> <td>1:30,000</td> <td><ul> <li>NOAA Marine charts</li> </ul></td> <td>2 min</td> <td>0.01 min</td> <td>1 sec</td> <td>10 m</td> <td>0.01 nm</td> </tr> </tbody></table>

### 1:30,750 Scale Map Ruler
https://maptools.com/product/Ruler30750

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><br /><tbody> <tr> <td>1:30,750</td> <td><ul> <li>Natl Geo Kiosk</li> <li>!TOPO Maps</li> </ul></td> <td>2.5 min</td> <td>0.01 min</td> <td>1 sec</td> <td>10 m</td> <td>0.01 m</td> </tr> </tbody></table>

### 1:300,000 Scale Map Ruler
https://maptools.com/product/Ruler300

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:300,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Alaska</li> <li>New Mexico</li> </ul> </ul></td> <td>30 min</td> <td>0.1 min</td> <td>10 sec</td> <td>100 m</td> <td>0.1 mi</td> </tr> </tbody></table>

### 1:320,000 Scale Map Ruler
https://maptools.com/product/Ruler320

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody> <tr> <td>1:320,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Colorado</li> </ul> </ul></td> <td>30 min</td> <td>0.1 min</td> <td>10 sec</td> <td>100 m</td> <td>0.1 mi</td> </tr> </tbody></table>

### 1:40,000 Scale Nautical Map Ruler
https://maptools.com/product/Ruler40N

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or nautical miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody> <tr> <td>1:40,000</td> <td><ul> <li>NOAA Marine charts</li> </ul></td> <td>2.5 min</td> <td>0.01 min</td> <td>1 sec</td> <td>25 m</td> <td>0.01 nm</td> </tr> </tbody></table>

### 1:40,680 Scale Map Ruler
https://maptools.com/product/Ruler40680

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><br /><tbody><tr> <td>1:40,680</td> <td><ul> <li>National Geographic Trails Illustrated Maps</li> </ul></td> <td>4 min</td> <td>0.01 min</td> <td>1 sec</td> <td>50 m</td> <td>0.01 mi</td> </tr> </tbody></table>

### 1:400,000 Scale Map Ruler
https://maptools.com/product/Ruler400

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody> <tr> <td>1:400,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Alaska</li> <li>Texas</li> </ul> </ul></td> <td>30 min</td> <td>0.5 min</td> <td>15 sec</td> <td>500 m</td> <td>0.5 mi</td> </tr> </tbody></table>

### 1:5,000 Scale Nautical Map Ruler
https://maptools.com/product/Ruler5N

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or nautical miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:5,000</td> <td><ul> <li>NOAA Marine charts</li> </ul></td> <td>0.5 min</td> <td>0.01 min</td> <td>1 sec</td> <td>5 m</td> <td>0.005 nm</td> </tr> </tbody></table>

### 1:50,000 Scale Map Ruler
https://maptools.com/product/Ruler50

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody> <tr> <td>1:50,000</td> <td><ul> <li>Canadian National Topographic System (NTS) maps</li> <li>USGS County series topographic maps</li> </ul></td> <td>5 min</td> <td>0.01 min</td> <td>1 sec</td> <td>50 m</td> <td>0.05 mi</td> </tr> </tbody></table>

### 1:50,000 Scale Pocket Size UTM Grid — Fast and easy UTM plotting
https://maptools.com/product/UTMGrid50

An easy to use grid tool that divides four 1 kilometer grid squares into 100 meter squares. Align the tool on the map grid and read off the easting and northing (sku,version,type,description) VALUES. The tool also has a compass rose protractor along the outside edge. This makes plotting or measuring a bearing a snap. The small size of the tool allows you to keep it handy in your pocket.<br /><br /> A band of white ink around the edge makes reading the compass rose and grid numbers easier and also keeps the tool from "disappearing" when you place it on the map. There is a lanyard hole in the upper left corner.<br /><br /> Printed on 30 mil plastic stock the tools are about the thickness of a credit card. The ink is coated to protect it from abrasion.<br />

### 1:50,000 Scale Stainless Steel Ruler — 0-30 kilometers,  0-18 miles, and 15 minutes of Latitude
 
https://maptools.com/product/SSRuler50

<p>We designed this ruler for military jump masters planning parachute drops. Since then a number of other military units have found it to be a useful planning tool for a variety of missions. </p> <p> The front side of the ruler measures kilometers (0-30km, smallest interval is 50m) on a 1:50,000 scale map. Both edges on the front side are marked for measuring kilometers, the zero end is on opposite ends of the ruler. </p> <p> The back side has one edge marked in statute miles (0-18 miles, smallest increment 0.05 mi.) The other edge is marked for latitude (15 minutes, smalls interval 0.05 min.) This edge will measure latitude directly and longitude when used on a diagonal as with our other lat/lon rulers. </p> <p> The ruler has a hanging hole on one end. </p> <p> <b>Need a custom design...</b> </p> <p> We can now do custom stainless steel rulers. We have a minimum quantity of 100 rulers and there is typically a 60-90 lead time. Please contact us for further information.</p>

### 1:500,000 Scale Map Ruler
https://maptools.com/product/Ruler500

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:500,000</td> <td><ul> <li>USGS State Base Maps</li> <li>NOAA Aeronautical Sectionals</li> </ul></td> <td>30 min</td> <td>0.5 min</td> <td>30 sec</td> <td>500 m</td> <td>0.5 mi</td> </tr> </tbody></table>

### 1:62,500 Scale Map Ruler
https://maptools.com/product/Ruler62

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:62,500</td> <td><ul> <li>USGS 15 minute topographic maps</li> </ul></td> <td>5 min</td> <td>0.05 min</td> <td>1 sec</td> <td>50 m</td> <td>0.05 mi</td> </tr> </tbody></table>

### 1:63,360 Scale Map Ruler
https://maptools.com/product/Ruler63

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:63,360</td> <td><ul> <li>USGS 15 minute topographic maps of Alaska</li> <li>1 inch = 1 mile</li> </ul></td> <td>5 min</td> <td>0.05 min</td> <td>1 sec</td> <td>50 m</td> <td>0.05 mi</td> </tr> </tbody></table>

### 1:65,000 Scale Map Ruler
https://maptools.com/product/Ruler65

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:65,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Connecticut</li> </ul> </ul></td> <td>5 min</td> <td>0.05 min</td> <td>1 sec</td> <td>50 m</td> <td>0.05 mi</td> </tr> </tbody></table>

### 1:69,500 Scale Map Ruler
https://maptools.com/product/Ruler69

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:69,500</td> <td><ul> <li>Green Trails Maps of Washington &amp; Oregon</li> </ul></td> <td>5 min</td> <td>0.05 min</td> <td>1 sec</td> <td>50 m</td> <td>0.05 mi</td> </tr> </tbody></table>

### 1:75,000 Scale Map Ruler
https://maptools.com/product/Ruler75

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><br /><tbody> <tr> <td>1:75,000</td> <td><ul> <li>Some National Geographic Trails Illustrated Maps</li> </ul> </ul></td> <td>5 min</td> <td>0.05 min</td> <td>1 sec</td> <td>100 m</td> <td>0.05 m</td> </tr> </tbody></table>

### 1:77,000 Scale Nautical Map Ruler
https://maptools.com/product/Ruler77N

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in nautical miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:77,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>New Jersey</li> </ul> </ul></td> <td>5 min</td> <td>0.05 min</td> <td>1 sec</td> <td>50 m</td> <td>0.05 nm</td> </tr> </tbody></table>

### 1:80,000 Scale Nautical Map Ruler
https://maptools.com/product/Ruler80N

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or nautical miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:80,000</td> <td><ul> <li>NOAA Marine charts</li> </ul></td> <td>5 min</td> <td>0.05 min</td> <td>1 sec</td> <td>50 m</td> <td>0.05 nm</td> </tr> </tbody></table>

### 1:80,000 Scale x 7.5 min Nautical Map Ruler
https://maptools.com/product/Ruler80NL

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or nautical miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in either miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:80,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Massachusetts</li> </ul> </ul></td> <td>7.5 min</td> <td>0.05 min</td> <td>1 sec</td> <td>50 m</td> <td>0.05 nm</td> </tr> </tbody></table>

### 1:84,000 Scale Nautical Map Ruler
https://maptools.com/product/Ruler84N

<p>This ruler can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the ruler has minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the ruler has distance in meters on one edge, and distance in nautical miles on the other edge.</p> <p>Latitude is measured directly with the ruler. But, since a degree of longitude covers a shorter distance as you move towards the poles, the ruler is used on a diagonal to measure longitude. See the usage diagrams for more information.</p> <p>The ruler is packaged in a handy clear vinyl storage pouch, and includes instructions for use.</p> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br /> Increments<br />in Minutes</td> <td> Ruler<br /> Increments <br />in Seconds</td> <td> Ruler<br /> Increments <br />in meters</td> <td> Ruler<br /> Increments <br />in Miles or<br /> Nautical Miles</td> </tr> </thead><tbody><tr> <td>1:84,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Hawaii</li> </ul> </ul></td> <td>7.5 min</td> <td>0.05 min</td> <td>1 sec</td> <td>50 m</td> <td>0.05 nm</td> </tr> </tbody></table>

### Acreage Estimator for 1:24,000 — Distance in miles, feet, and chains, UTM in meters
https://maptools.com/product/AcreageEst24

<p>Our acreage estimator covers two square miles in 10 acre squares. Each 10 acre square has a dot in the center. You can use the dot as the include/exclude point, or you can use the dot to define 2.5 acre squares. Off to the side, the tool also has a small section divided into 2 acre squares with center dots. Around the edges of the tool there are distance rulers marked in: chains, tenths of miles, and feet. The lower right corner has a 1km corner ruler for plotting UTM coordinates.</p>

### Adventure Racing Corner Rulers — One Tool, 5 Common Scales
https://maptools.com/product/AdvCorner

<p>Five corner rulers on a single card covering the most common map scales used in adventure races. Each corner ruler allows you to plot a UTM coordinate within a 1km map grid with 10m precision. Each corner has a small hole to allow for placing a mark on the map.</p>

### Adventure Set of 4 Map Rulers — 1:24,000 1:62,500 1:100,000 1:126,720
https://maptools.com/product/AdventureSet

<p>The four most common map scales an outdoor adventurer will encounter in the Continental United States. </p> <p>These rulers can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the rulers have minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the rulers have distance in meters on one edge, and distance in either miles on the other edge. </p> <p>Latitude is measured directly with the rulers. But, since a degree of longitude covers a shorter distance as you move towards the poles, the rulers are used on a diagonal to measure longitude. See the usage diagrams for more information. </p> <p>The rules are packaged in a handy clear vinyl storage pouch, and includes instructions for use. </p><br /> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br> Increments<br> in Minutes </td> <td> Ruler<br> Increments<br> in Seconds </td> <td> Ruler<br> Increments<br> in meters </td> <td> Ruler<br> Increments<br> in Miles or<br> Nautical Miles </td> </tr> </thead> <tbody> <tr> <td>1:24,000</td> <td><ul> <li>USGS 7.5 minute topographic maps</li> </ul></td> <td>2.5 min</td> <td>0.01 min</td> <td>1 sec</td> <td>10 m</td> <td>0.01 mi</td> </tr> <tr> <td>1:62,500</td> <td><ul> <li>USGS 15 minute topographic maps</li> </ul></td> <td>5 min</td> <td>0.05 min</td> <td>1 sec</td> <td>50 m</td> <td>0.05 mi</td> </tr> <tr> <td>1:100,000</td> <td><ul> <li>USGS &amp; BLM 30 X 60 minute topographic maps</li> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Delaware</li> <li>Maryland</li> <li>New Hampshire</li> <li>Vermont</li> </ul> </ul></td> <td>10 min</td> <td>0.05 min</td> <td>5 sec</td> <td>50 m</td> <td>0.1 mi</td> </tr> <tr> <td>1:126,720</td> <td><ul> <li>US Forest Service forest maps</li> <li>1/2 inch = 1 mile maps</li> </ul></td> <td>7.5 min</td> <td>0.05 min</td> <td>5 sec</td> <td>50 m</td> <td>0.1 mi</td> </tr> </tbody> </table>

### Aerial Photo UTM Corner Rulers — Lots of Scales, More Precision
https://maptools.com/product/AirCorner

<p>Four corner rulers on a single card covering the most common scales used for aerial photography. Each corner ruler allows you to plot a UTM coordinate within a 500m map grid with 10m precision. Each corner has a small hole to allow for placing a mark on the photo or map.</p>

### British Columbia UTM Slots
https://maptools.com/product/UTM-BC

A pocket sized tool that covers the 1:20,000 scale used on the British Columbia TRIM Maps (Terrain Resources Inventory Mapping) and the 1:50,000 scale used on the Canadian NTS maps (National Topographic System).

### Classroom Training Compass Visual Aid
https://maptools.com/product/Compass-TA

<p>This is a demonstration baseplate compass that is big enough to hold up in front of a classroom and be seen by your students. You can demonstrate common compass skills including:</p> <ul> <li>Orienting yourself and your map with North and the cardinal directions</li> <li>Sighting a bearing to a distant object</li> <li>Traveling along a heading</li> <li>Plotting a bearing on your map</li> </ul> <p>The compass can be adjusted for declination and grid variance, and you will be able to show your student how to do this and what their compass should look like when correctly adjusted. Just like in a real compass, the orienting arrow is on separate layer from the orienting arrow and protractor dial. There are angular markings to help position the orienting arrow at a fixed angle from the orienting lines and the protractor dial. This compass uses a dot of velcro to fix the adjustment position.</p> <p>Please note this is not a functional compass. The needle is not magnetized and will not align itself with magnetic north.</p> <p>Here is a link to a page that describes <a href="/large-training-aids">how to use our line of large teaching aid products.</a> </p> <h3>Specifications</h3> <ul> <li>Base plate dimensions: 14” x 10” x 1/8”</li> <li>Dial and Capsule diameter: 9 3/4”</li> <li>Dial markings: 360° in 2° increments, Cardinal directions of N, S, E, and W are labeled</li> <li>It is possible to special order dials marked in 90° quadrants on in mils.</li> <li>Weight: 15 oz.</li> <li>Overall thickness: 0.6”</li> <li>Central pivot: A Chicago Screw holds it all together, but is easily unscrewed to change out dials or other parts. Fuzzy washers make it easy to move the needle and dial while providing enough friction that they will stay in position.</li> </ul> <p>This product pairs nicely with some of our other tools and instructional handouts.</p> <ul> <li><a href="/product/Map1-TA">Map for use with Large Classroom Training Aids</a> </li> <li><a href="/product/RoundGTA">Round Military Coordinate Scale and Protractor (or any of our other tools with a protractor)</a> </li> <li><a href="/product/Card_Dec">Reference Card - Declination & Compass Rose</a> </li> <li><a href="/declination">Custom Reference Sheet for Magnetic Declination and Grid Variance</a> </li> <li><a href="/product/NorthRefSheet">Reference Card - North Reference Sheet</a> </li> </ul>

### Custom Declination Reference Sheet — Custom Declination Reference Sheet
https://maptools.com/product/Cust_DecRefSheet

Custom Declination Reference Sheet

### Custom Map Ruler
https://maptools.com/product/Cust_Ruler

### Green Trails UTM Slots — Pocket sized
https://maptools.com/product/UTM-GT

Green Trails produces and execelent series of maps covering popular recreation areas in Washington and Oregon. Most of their maps cover a 15 minute area, using the 1:69,500 scale. A few of their special series maps use other scales, so be sure to check which scale you need.

### Improved Military Style UTM/MGRS Coordinate Scale — Compass Rose in both Degrees and Mils
https://maptools.com/product/SuperGTA

This tool is an improved version of the Graphic Training Aid 5-2-12 Coordinate Scale and Protractor used by United States and NATO military forces around the world. By using a slot on one side of the tool for access to the map, the tool can be more compact than the traditional GTA tool. The tool features several additional map scales, including 1:24,000, which is the most common topographic map scale found within the United States. The 1:100,000 scale now spans 5km grid lines, making it much more usable. Plus, the overall dimensions of the tool have been reduced so that it is the size of a music CD, easily fitting into a pocket or any slot where you could store a CD.<br /><br /> The inner protractor is marked in degrees and the outer protractor is in mils.<br /><br /> Bands of white ink are printed under the two compass roses. This makes reading the compass rose easier and also keeps the tool from "disappearing" when you place it on the map.<br /><br /> Our coordinate scales offer significant benefits over the standard issue GTA 5-2-12:<br /><ul> <li>The tool is printed on plastic stock about the thickness and stiffness of a credit card, with a protective coating. It's 33% thicker than the standard military issue version, so it's less likely to be bent or broken when you need to use it.</li><li>Rounded corners keep it from wearing holes in your pockets.</li><li>Includes 1:24,000 scale for USGS 7.5 minute topographic maps.</li><li>Larger 1:50,000 and 1:100,000 scale rulers for maps with wider grid spacing.</li><li>It's the size of a music CD, so it tucks away in more storage spaces.</li></ul>

### Inch/Metric Ruler — inches in 1/8ths and 1/10ths, millimeters
https://maptools.com/product/RulerInch

<p>The front side has two 8 inch scales, one marked in 1/16ths of an inch and the other in 1/10ths of an inch. The flip side has a 200 millimeter ruler, and 10 numeric unit conversion factors listed. This is an excellent tool for working with odd scale maps where you need to use a ratio calculation to determine distances and coordinate readings.</p>

### Land Sectioning Tool for 1:24,000 — For dividing public land survey township and range sections
https://maptools.com/product/LandSection24

Our Land Sectioning Tool for 1:24,000 scale maps features a square mile section divided into 10 acre squares. Each 10 acre square has holes at the corners to allow you to mark out smaller divisions of land within the section lines printed on the map. The tool also includes cutouts for drawing squares that are 40, 10, or 2.5 acres in size. There is a handy section number reference diagram. Along the edges of the tool are rulers marked in tenths of miles and feet.

### Large Magnifier — A tool for those of us for whom the contour lines have begun to blur together.
https://maptools.com/product/LrgMag

These small plastic fresnel magnifiers offer a light weight, non-breakable alternative to your reading glasses or a glass lens magnifier. They provide a 2X magnification when held about 2” away from the map. These magnifiers have a hole in the corner for a lanyard and come packaged in a protective sleeve. They are available in two sizes.<br /><br />A fresnel lens replaces the curved surface of a conventional lens with a series of concentric groves molded into the surface of a thin, lightweight plastic sheet. The grooves act as individual refracting surfaces, like tiny prisms when viewed in cross sections, bending parallel rays in a very close approximation to a common focal length which, designed properly, is more efficient at gathering light then a standard lens.

### Locating Coordinate Grid Information on USGS Maps
https://maptools.com/product/GridsSheet

This is a handout I use in my navigation classes. This is a full color page with a sample map showing where to find coordinate grid information for UTM and Latitude/Longitude on USGS topographic maps. Public land survey sections and State Plane coordinates are also shown. You can <a href="../../pdfs/instructors/LocatingTheGrids.pdf"> download the pdf for free</a>. We'll send you a copy with your order for free. Or, if you need a bunch for your class, we sell them for less than you could print them on your own printer.<p>Note: The answers for the exercise questions 3 & 4 are reversed. The answer to Q. 3 is A. 4, and vise versa.</p>

### Map Bag - Big — To protect maps printed on 11"x17" or A3 paper or larger sheets with a fold or two.
https://maptools.com/product/MapBagBig

<p> If you are lucky enough to be able to print your maps on 11"x17" paper or you are using full sized map sheets this is the map bag for you. At 13"x18" this 4 mil polyethylene bag is a simple and affordable solution for weather protection of your maps. The bag will hold USGS 1:24,000 scale maps folded into quarters, or 11"x17" sheets without folding. </p>If you need to protect smaller letter sized maps see our <a href="MapBagSmall">Small Map Bag</a> <p>You can spend a lot more on a fancy map pouch, but why?</p> <p>There is a small gotcha with these bags. They don't fit into an envelope we can send by First Class Mail. So they will bump your order up to Priority Mail shipping.</p>

### Map Bag - Small — To protect maps printed on letter or A4 paper
https://maptools.com/product/MapBagSmall

<p> Protect the maps you print from the weather. This polyethylene bag is a simple and affordable solution for weather protection of maps printed on letter or A4 sized paper. Their 4mil thickness will hold up to the rigors of field use. </p>If you need to protect larger maps see our <a href="MapBagBig">Large Map Bag</a> <p>You can spend a lot more on a fancy map pouch, but why?</p>

### Map for use with Large Classroom Training Aids
https://maptools.com/product/Map1-TA

<p>This is a laminated training map designed to be used with our classroom training aid products. </p> <ul> <li><a href="product/UTMGrid-TA">UTM Grid Style Classroom Training Aid</a></li> <li><a href="product/UTMSlot-TA">UTM Slot Style Classroom Training Aid</a></li> <li><a href="product/CornerRuler-TA">Corner Ruler Style Classroom Training Aid</a></li> <li><a href="product/MiniCorner-TA">Mini Corner Style Classroom Training Aid</a></li> <li><a href="product/MapRuler-TA">Map Ruler Style Classroom Training Aid</a></li> </ul> <p>The map is printed at 1:6.369 scale and laminated so you can use it with dry erase or alcohol based pens over and over again.The map measures 36" x 48" and ships rolled up in a cardboard tube.</p> <p>You can make your own topo map at 1:6,369. Here is a link to a downloadable <a href="/images/Usage/V4E94.tiff"> training map I made</a> using <a href="https://CalTopo.com">CalTopo.com</a> You can get it printed at <a href="https://posterbrain.com">PosterBrain.com</a> Their current pricing (April 2022) is $54 for printing (36x48), $12 for lamination, $8 for Priority Mail shipping. </p> <p>We charge more than they do, but then we are doing the work. It's easy and you should really do it yourself.</p> <p>Some tips for making your own CalTopo Training map</p> <ul> <li>- You’ll need a paid CalTopo subscription to generate large PDFs</li> <li>- I created a 36" x 48" map.</li> <li>- Use a 1:6,369 scale. (Chose Custom Scale and enter 6369.)</li> <li>- Use 1km UTM Grid lines</li> <li>- If you are using a USGS scanned base map with printed UTM Grid lines, you’ll likely want to use the NAD27 datum or you will have 2 sets of grid lines, which makes for a confusing demo.</li> <li>- The coordinate labels will be in a tiny type size. Plan to add them by hand if you want the class to be able to see them.</li> <li>- PosterBrain has a max file size of 100 MB. I exported the pdf file as a 150 dpi TIFF file to get it under 100 MB.</li> </ul> <p>Laminate the map, so you can reuse it.</p> <h3>Note:</h3> <p>While this map is the same scale as our <a href="/product/MapRuler-TA">Map Ruler Classroom Training Aid</a>, it <strong>does not have any latitude longitude markings on it.</strong> There is room for a 2.5 minute lat/lon grid, so you could "make one up" and draw the grid markings and labels on the map with a marker. But the map is positioned such that it would span several partial 2.5 minute grids of actual lat/lon coordinates. If you want a map like this to teach lat/lon, please contact me and I can create one for you. </p>

### Map Math Instruction Sheet
https://maptools.com/product/MapMathSheet

This is a handout I use in my navigation classes. It is a quad fold sheet of information about map scale calculations and distance unit conversions. It includes a ruler marked in tenths of inches and milimeters. You can <a href="../../pdfs/instructors/MapMathSheet.pdf"> download the pdf for free</a>. We'll send you a copy with your order for free. Or, if you need a bunch for your class, we sell them for less than you could print them on your own printer.

### Map Ruler -- Large Classroom Training Aid — Measures lat/lon, miles, and kilometer
https://maptools.com/product/MapRuler-TA

<p>This is a large Ruler style tool intended for use in a classroom teaching situation. It is about 4 times the size of our regular tools. That means you can hold it up to the whiteboard to demonstrate how to use it, and you students can see it.</p> <p>There is also a hole in the end that you can use to hand the tool from a nail or peg, to keep it handy. I put a self adhesive backed hook on the edge on my whiteboard to hang my training aids from.</p> <p>Here is a link to a page that describes <a href="/large-training-aids">how to use our line of large teaching aid products.</a> </p> <p>This product pairs nicely with some of our other tools and instructional handouts.</p> <ul> <li><a href="/product/Map1-TA">Map for use with Large Classroom Training Aids</a> </li> <li><a href="/product/Ruler24">1:24,000 Scale Map Ruler</a> </li> <li><a href="/product/Ruler25">1:25,000 Scale Map Ruler</a> </li> <li><a href="/product/Card_LatLon">Reference Card - Latitude Longitude</a> </li> <li><a href="/product/Card_Dist">Reference Card - Time, Speed, and Distance</a> </li> <li><a href="/product/GridsSheet">Locating Coordinate Grid Information on USGS Maps Handout and Practice Map</a> </li> <li><a href="/product/MapMathSheet">Map Math Instruction Sheet</a> </li> </ul>

### Map Rulers - Explorer Set of MapRulers
https://maptools.com/product/ExplorerSet

<p>Rulers that should cover some of the maps you’re likely to encounter in land navigation.</p> <p>These rulers can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the rulers have minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the rulers have distance in meters on one edge, and distance in either miles on the other edge. </p> <p>Latitude is measured directly with the rulers. But, since a degree of longitude covers a shorter distance as you move towards the poles, the rulers are used on a diagonal to measure longitude. See the usage diagrams for more information. </p> <p>The rules are packaged in a handy clear vinyl storage pouch, and includes instructions for use. </p> <br /> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br> Increments<br> in Minutes </td> <td> Ruler<br> Increments<br> in Seconds </td> <td> Ruler<br> Increments<br> in meters </td> <td> Ruler<br> Increments<br> in Miles or<br> Nautical Miles </td> </tr> </thead> <tbody> <tr> <td>1:24,000</td> <td><ul> <li>USGS 7.5 minute topographic maps</li> </ul></td> <td>2.5 min</td> <td>0.01 min</td> <td>1 sec</td> <td>10 m</td> <td>0.01 mi</td> </tr> <tr> <td>1:25,000</td> <td><ul> <li>USGS 7.5 minute topographic maps of Alaska and a few places in the Continental United States</li> </ul></td> <td>2.5 min</td> <td>0.01 min</td> <td>1 sec</td> <td>10 m</td> <td>0.01 mi</td> </tr> <tr> <td>1:50,000</td> <td><ul> <li>Canadian National Topographic System (NTS) maps</li> <li>USGS County series topographic maps</li> </ul></td> <td>5 min</td> <td>0.01 min</td> <td>1 sec</td> <td>50 m</td> <td>0.05 mi</td> </tr> <tr> <td>1:62,500</td> <td><ul> <li>USGS 15 minute topographic maps</li> </ul></td> <td>5 min</td> <td>0.05 min</td> <td>1 sec</td> <td>50 m</td> <td>0.05 mi</td> </tr> <tr> <td>1:63,360</td> <td><ul> <li>USGS 15 minute topographic maps of Alaska</li> <li>1 inch = 1 mile</li> </ul></td> <td>5 min</td> <td>0.05 min</td> <td>1 sec</td> <td>50 m</td> <td>0.05 mi</td> </tr> <tr> <td>1:69,500</td> <td><ul> <li>Green Trails Maps of Washington &amp; Oregon</li> </ul></td> <td>5 min</td> <td>0.05 min</td> <td>1 sec</td> <td>50 m</td> <td>0.05 mi</td> </tr> <tr> <td>1:77,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>New Jersey</li> </ul> </ul></td> <td>5 min</td> <td>0.05 min</td> <td>1 sec</td> <td>50 m</td> <td>0.05 nm</td> </tr> <tr> <td>1:80,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Massachusetts</li> </ul> </ul></td> <td>7.5 min</td> <td>0.05 min</td> <td>1 sec</td> <td>50 m</td> <td>0.05 nm</td> </tr> <tr> <td>1:100,000</td> <td><ul> <li>USGS &amp; BLM 30 X 60 minute topographic maps</li> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Delaware</li> <li>Maryland</li> <li>New Hampshire</li> <li>Vermont</li> </ul> </ul></td> <td>10 min</td> <td>0.05 min</td> <td>5 sec</td> <td>50 m</td> <td>0.1 mi</td> </tr> <tr> <td>1:125,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Maine (Old editions. New editions are 1:135,000)</li> </ul> </ul></td> <td>7.5 min</td> <td>0.05 min</td> <td>5 sec</td> <td>50 m</td> <td>0.1 mi</td> </tr> <tr> <td>1:126,720</td> <td><ul> <li>US Forest Service forest maps</li> <li>1/2 inch = 1 mile maps</li> </ul></td> <td>7.5 min</td> <td>0.05 min</td> <td>5 sec</td> <td>50 m</td> <td>0.1 mi</td> </tr> <tr> <td>1:150,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>California</li> <li>Florida</li> <li>Illinois</li> <li>Kentucky</li> <li>Michigan</li> <li>New York</li> <li>North Carolina</li> <li>Ohio</li> <li>Oklahoma</li> <li>Oregon</li> <li>Pennsylvania</li> <li>South Carolina</li> <li>Tennessee</li> <li>Virginia</li> <li>Washington</li> <li>West Virginia</li> <li>Wisconsin</li> </ul> </ul></td> <td>15 min</td> <td>0.1 min</td> <td>5 sec</td> <td>100 m</td> <td>0.1 mi</td> </tr> <tr> <td>1:160,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Colorado</li> </ul> </ul></td> <td>15 min</td> <td>0.05 min</td> <td>5 sec</td> <td>100 m</td> <td>0.1 mi</td> </tr> <td>1:200,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Alabama</li> <li>Arkansas</li> <li>Iowa</li> <li>Kansas</li> <li>Missouri</li> <li>Nebraska</li> <li>North Dakota</li> <li>South Dakota</li> </ul> </ul></td> <td>15 min</td> <td>0.1 min</td> <td>10 sec</td> <td>100 m</td> <td>0.1 mi</td> </tr> <tr> <td>1:250,000</td> <td><ul> <li>USGS 1 X 2 degree series topographic maps</li> <li>Canadian National Topographic System (NTS) maps</li> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Arizona (Old editions. New editions are 1:260,000)</li> <li>Idaho</li> <li>Montana</li> <li>Nevada</li> <li>Utah (Old editions. New editions are 1:235,000)</li> <li>Wyoming (Old editions. New editions are 1:225,000)</li> </ul> </ul> <td>15 min</td> <td>0.1 min</td> <td>15 sec</td> <td>100 m</td> <td>0.1 mi</td> </tr> <tr> <td>1:300,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Alaska</li> <li>New Mexico</li> </ul> </ul></td> <td>30 min</td> <td>0.1 min</td> <td>10 sec</td> <td>100 m</td> <td>0.1 mi</td> </tr> <tr> <td>1:320,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Colorado</li> </ul> </ul></td> <td>30 min</td> <td>0.1 min</td> <td>10 sec</td> <td>100 m</td> <td>0.1 mi</td> </tr> <tr> <td>1:400,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Alaska</li> <li>Texas</li> </ul> </ul></td> <td>30 min</td> <td>0.5 min</td> <td>15 sec</td> <td>500 m</td> <td>0.5 mi</td> </tr> <tr> <td>1:500,000</td> <td><ul> <li>USGS State Base Maps</li> <li>NOAA Aeronautical Sectionals</li> </ul></td> <td>30 min</td> <td>0.5 min</td> <td>30 sec</td> <td>500 m</td> <td>0.5 mi</td> </tr> <tr> <td>Length</td> <td><ul> <li>The front side has two 8 inch scales, one marked in 1/16ths of an inch and the other in 1/10ths of an inch. The flip side has a 200 millimeter ruler, and 10 numeric unit conversion factors listed.</li> </ul></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <!---<tr> <td>Unit Conversion</td> <td><ul> <li>Two graphical scales to enable you to convert between miles and kilometers or feet and meters, without the need of any calculations</li> </ul></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> ---> </tbody> </table>

### Map Rulers - USGS Set of 10 Map Rulers — Scales for most maps published by USGS
https://maptools.com/product/USGSSet

<p>Ten rulers covering the common map scales used by the USGS, Forest Service, and BLM.</p> <p>These rulers can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles. </p> <p>On the front side, the rulers have minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the rulers have distance in meters on one edge, and distance in either miles on the other edge. </p> <p>Latitude is measured directly with the rulers. But, since a degree of longitude covers a shorter distance as you move towards the poles, the rulers are used on a diagonal to measure longitude. See the usage diagrams for more information. </p> <p>The rules are packaged in a handy clear vinyl storage pouch, and includes instructions for use. </p><br /> <table class="rulerspec"> <thead> <tr> <td rowspan="2">Scale</td> <td rowspan="2">Maps</td> <td colspan="3">Front Side</td> <td colspan="2">Back Side</td> </tr> <tr> <td>Span</td> <td> Ruler<br> Increments<br> in Minutes </td> <td> Ruler<br> Increments<br> in Seconds </td> <td> Ruler<br> Increments<br> in meters </td> <td> Ruler<br> Increments<br> in Miles or<br> Nautical Miles </td> </tr> </thead> <tbody> <tr> <td>1:24,000</td> <td><ul> <li>USGS 7.5 minute topographic maps</li> </ul></td> <td>2.5 min</td> <td>0.01 min</td> <td>1 sec</td> <td>10 m</td> <td>0.01 mi</td> </tr> <tr> <td>1:25,000</td> <td><ul> <li>USGS 7.5 minute topographic maps of Alaska and a few places in the Continental United States</li> </ul></td> <td>2.5 min</td> <td>0.01 min</td> <td>1 sec</td> <td>10 m</td> <td>0.01 mi</td> </tr> <tr> <td>1:50,000</td> <td><ul> <li>Canadian National Topographic System (NTS) maps</li> <li>USGS County series topographic maps</li> </ul></td> <td>5 min</td> <td>0.01 min</td> <td>1 sec</td> <td>50 m</td> <td>0.05 mi</td> </tr> <tr> <td>1:62,500</td> <td><ul> <li>USGS 15 minute topographic maps</li> </ul></td> <td>5 min</td> <td>0.05 min</td> <td>1 sec</td> <td>50 m</td> <td>0.05 mi</td> </tr> <tr> <td>1:63,360</td> <td><ul> <li>USGS 15 minute topographic maps of Alaska</li> <li>1 inch = 1 mile</li> </ul></td> <td>5 min</td> <td>0.05 min</td> <td>1 sec</td> <td>50 m</td> <td>0.05 mi</td> </tr> <tr> <td>1:100,000</td> <td><ul> <li>USGS &amp; BLM 30 X 60 minute topographic maps</li> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Delaware</li> <li>Maryland</li> <li>New Hampshire</li> <li>Vermont</li> </ul> </ul></td> <td>10 min</td> <td>0.05 min</td> <td>5 sec</td> <td>50 m</td> <td>0.1 mi</td> </tr> <tr> <td>1:125,000</td> <td><ul> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Maine (Old editions. New editions are 1:135,000)</li> </ul> </ul></td> <td>7.5 min</td> <td>0.05 min</td> <td>5 sec</td> <td>50 m</td> <td>0.1 mi</td> </tr> <tr> <td>1:126,720</td> <td><ul> <li>US Forest Service forest maps</li> <li>1/2 inch = 1 mile maps</li> </ul></td> <td>7.5 min</td> <td>0.05 min</td> <td>5 sec</td> <td>50 m</td> <td>0.1 mi</td> </tr> <tr> <td>1:250,000</td> <td><ul> <li>USGS 1 X 2 degree series topographic maps</li> <li>Canadian National Topographic System (NTS) maps</li> <li>Delorme Atlas &amp; Gazetteers for:</li> <ul> <li>Arizona (Old editions. New editions are 1:260,000)</li> <li>Idaho</li> <li>Montana</li> <li>Nevada</li> <li>Utah (Old editions. New editions are 1:235,000)</li> <li>Wyoming (Old editions. New editions are 1:225,000)</li> </ul> </ul> <td>15 min</td> <td>0.1 min</td> <td>15 sec</td> <td>100 m</td> <td>0.1 mi</td> </tr> <tr> <td>1:500,000</td> <td><ul> <li>USGS State Base Maps</li> <li>NOAA Aeronautical Sectionals</li> </ul></td> <td>30 min</td> <td>0.5 min</td> <td>30 sec</td> <td>500 m</td> <td>0.5 mi</td> </tr> <tr> <td>Length</td> <td><ul> <li>The front side has two 8 inch scales, one marked in 1/16ths of an inch and the other in 1/10ths of an inch. The flip side has a 200 millimeter ruler, and 10 numeric unit conversion factors listed.</li> </ul></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <!--- <tr> <td>Unit Conversion</td> <td><ul> <li>Two graphical scales to enable you to convert between miles and kilometers or feet and meters, without the need of any calculations</li> </ul></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> ---> </tbody> </table>

### Military Style UTM/MGRS Coordinate Scale — Coordinate Scale and Protractor - GTA 5-2-12
https://maptools.com/product/GTA

This tool is equivalent to the Graphic Training Aid 5-2-12 and Protractor used by United States and NATO military forces around the world. The scale has three die cut triangles for access to mark the map being measured. The inner protractor is marked in degrees and the outer protractor is in mils.

### Mini Corner -- Large Classroom Training Aid
https://maptools.com/product/MiniCorner-TA

<p>This is a large UTM Mini Corner style tool intended for use in a classroom teaching situation. It is about 4 times the size of our regular tools. That means you can hold it up to the whiteboard to demonstrate how to use it, and you students can see it.</p> <p>You can easily mark a grid on the whiteboard for your demo map. Just use the tool to measure out and mark the corners with a dot. Do as many grids as you want, and then connect the dots with a straight edge and your whiteboard marker. Add some grid coordinate labels and you are ready to demo UTM coordinates.</p> <p>The actual scale of the tool works out to 1:6,369. Use that scale if you want to create a map image for printing on a large sheet of paper to use with the tool, using a service like CalTopo.com to create your pdf file. If you want to enlarge part of a 1:24,000 scale map, enlarge it by 377%. (24000 / 6369 * 100)</p> <p>We use the same scale for our UTM Grid style classroom training aid, so it’s easy to move students from the conceptually simple idea of the grid tool that just fits inside the grid, to the more complicated, but more precise, measurements they can make with a mini corner style tool.</p> <p>There is also a hole in the corner that you can use to hand the tool from a nail or peg, to keep it handy. I put a self adhesive backed hook on the edge on my whiteboard to hang my training aids from.</p> <p>Here is a link to a page that describes <a href="/large-training-aids">how to use our line of large teaching aid products.</a> </p> <p>This product pairs nicely with some of our other tools and instructional handouts.</p> <ul> <li><a href="/product/Map1-TA">Map for use with Large Classroom Training Aids</a> </li> <li><a href="/product/Mini24">Mini Corner Ruler for 1:24,000</a> </li> <li><a href="/product/Mini25">Mini Corner Ruler for 1:25,000</a> </li> <li><a href="/product/UTMGuide3">Using your GPS with UTM Coordinates Booklet 3rd Ed.</a> </li> <li><a href="/product/Card_UTM">Reference Card - UTM, MGRS, USNG</a> </li> <li><a href="/product/GridsSheet">Locating Coordinate Grid Information on USGS Maps Handout and Practice Map</a> </li> <li><a href="/product/MilStyleInsert">UTM Tool Instruction Sheet</a> </li> </ul>

### Mini Corner Ruler for 1:12,000
https://maptools.com/product/Mini12

These are our smallest UTM tools! Each Mini Corner has just one scale printed on it. The bottom edge is placed on the bottom of the map grid, making it easy to align the tool parallel to the grid lines. <br/><br/> Each tool has a hole to thread it onto a lanyard. <br/><br/> When we reprinted this tool we added a triangle of white ink under the numbers. This makes the numbers easier to read and also makes it easier to see the tool on your map.

### Mini Corner Ruler for 1:24,000
https://maptools.com/product/Mini24

These are our smallest UTM tools! Each Mini Corner has just one scale printed on it. The bottom edge is placed on the bottom of the map grid, making it easy to align the tool parallel to the grid lines. <br/><br/> Each tool has a hole to thread it onto a lanyard. <br/><br/> When we reprinted this tool we added a triangle of white ink under the numbers. This makes the numbers easier to read and also makes it easier to see the tool on your map.

### Mini Corner Ruler for 1:25,000
https://maptools.com/product/Mini25

These are our smallest UTM tools! Each Mini Corner has just one scale printed on it. The bottom edge is placed on the bottom of the map grid, making it easy to align the tool parallel to the grid lines. <br/><br/> Each tool has a hole to thread it onto a lanyard. <br/><br/> When we reprinted this tool we added a triangle of white ink under the numbers. This makes the numbers easier to read and also makes it easier to see the tool on your map.

### Mini Corner Ruler for 1:30,000
https://maptools.com/product/Mini30

These are our smallest UTM tools! Each Mini Corner has just one scale printed on it. The bottom edge is placed on the bottom of the map grid, making it easy to align the tool parallel to the grid lines.<br /><br />Each tool has a hole to thread it onto a lanyard.

### Mini Corner Ruler for 1:35,000
https://maptools.com/product/Mini35

These are our smallest UTM tools! Each Mini Corner has just one scale printed on it. The bottom edge is placed on the bottom of the map grid, making it easy to align the tool parallel to the grid lines.<br /><br />Each tool has a hole to thread it onto a lanyard.

### Mini Corner Ruler for 1:40,000
https://maptools.com/product/Mini40

These are our smallest UTM tools! Each Mini Corner has just one scale printed on it. The bottom edge is placed on the bottom of the map grid, making it easy to align the tool parallel to the grid lines.<br /><br />Each tool has a hole to thread it onto a lanyard.

### Mini Corner Ruler for 1:47,520
https://maptools.com/product/Mini47

These are our smallest UTM tools! Each Mini Corner has just one scale printed on it. The bottom edge is placed on the bottom of the map grid, making it easy to align the tool parallel to the grid lines.<br /><br />Each tool has a hole to thread it onto a lanyard.

### Mini Corner Ruler for 1:48,000
https://maptools.com/product/Mini48

These are our smallest UTM tools! Each Mini Corner has just one scale printed on it. The bottom edge is placed on the bottom of the map grid, making it easy to align the tool parallel to the grid lines.<br /><br />Each tool has a hole to thread it onto a lanyard.

### Mini Corner Ruler for 1:50,000
https://maptools.com/product/Mini50

These are our smallest UTM tools! Each Mini Corner has just one scale printed on it. The bottom edge is placed on the bottom of the map grid, making it easy to align the tool parallel to the grid lines. <br/><br/> Each tool has a hole to thread it onto a lanyard. <br/><br/> When we reprinted this tool we added a triangle of white ink under the numbers. This makes the numbers easier to read and also makes it easier to see the tool on your map.

### Mini Corner Ruler for 1:62,500
https://maptools.com/product/Mini62

These are our smallest UTM tools! Each Mini Corner has just one scale printed on it. The bottom edge is placed on the bottom of the map grid, making it easy to align the tool parallel to the grid lines.<br /><br />Each tool has a hole to thread it onto a lanyard.

### Mini Corner Ruler for 1:63,360
https://maptools.com/product/Mini63

These are our smallest UTM tools! Each Mini Corner has just one scale printed on it. The bottom edge is placed on the bottom of the map grid, making it easy to align the tool parallel to the grid lines.<br /><br />Each tool has a hole to thread it onto a lanyard.

### Natl Geo Kiosk and !TOPO Maps UTM Slots
https://maptools.com/product/UTM-NG

This pocket sized UTM tool is designed to be used with maps printed on National Geographic's MapMachine Kiosks, their online map printing service, or the default scale for maps printed from Topo! software.<br /><br /> Don't forget to turn on the UTM Grid option when you print your maps.<br />

### Natl. Geo. Trails Illustrated Maps UTM Slots for 1:40,680
https://maptools.com/product/UTM-TI

The National Geographic Trails Illustrated Series of maps is a large map series know for their excellent trail detail. The individual map focus on National Parks, National Forests, and BLM and other public lands.<br /><br /> The series uses many different map scales. Double check the scale of your map, to be sure you are ordering a suitable tool. At this time MapTools does not have tools for every scale that the series uses.<br /><br /> A band of white ink around the edge of the tool. This makes reading the compass rose and grid numbers easier and also keeps the tool from "disappearing" when you place it on the map.<br /><br /> Printed on plastic with a protective coating.

### North Reference Sheet
https://maptools.com/product/NorthRefSheet

This is a handout I use in my navigation classes. It is 4 pages of color info and illustrations all about using various North references. You can <a href="../../pdfs/instructors/NorthReferenceSheet.pdf"> download the pdf for free</a>. We'll send you a copy with your order for free. Or, if you need a bunch for your class, we sell them for less than you could print them on your own printer.

### Pocket Sized UTM Corner Rulers
https://maptools.com/product/PocketCorners

A pocket sized set of 3 UTM corner rulers or "roamers" for 1:24,000, 1:25,000, and 1:50,000 scale maps. The 1:24,000 and 1:25,000 corners allow you to divide a 1km map grid to a 10m precision. The 1:50,000 corner allows you to divide a 1km map grid to a 20m precision. The tool has a hole at the corner of each scale to allow for placing a mark on the map. There is also a hole in the center that allows a string to extend the compass rose. There is a lanyard hole in the upper left corner. <br /><br /> The tool has a band of white ink around the edge of the tool. This makes reading the compass rose and grid numbers easier and also keeps the tool from "disappearing" when you place it on the map.

### Pocket Sized UTM Slot Tool - 90 Degree Quadrants — Compass rose marked in 90 degree quadrants.
https://maptools.com/product/PocketSlotsQuads

A pocket sized tool with slot scales for 1:24,000, 1:25,000, and 1:50,000 scale maps. The 1:24,000 and 1:25,000 scales allow you to divide a 1km map grid with 10m precision. The 1:50,000 scale allows you to divide a 1km map grid with 20m precision. The tool also has a compass rose along its outside edge marked in 90 degree quadrants. This makes plotting or measuring a bearing a snap. The small size of this tool will allow you to keep it handy in your pocket. <br /><br />We also have this tool with a compass rose marked in degrees or mils, <a href="/product/PocketSlots">PocketSlots (degrees)</a><br/><br/><a href="/product/PocketSlotsMils">PocketSlotsMils</a><br/><br/>A band of white ink around the edge of the tool makes reading the compass rose easier and also keeps the tool from “disappearing” when you place it on the map. There is also a lanyard hole in the upper left corner. <br /><br />Printed on plastic stock, the tool is about the thickness of a credit card. The ink is coated to protect it from abrasion.

### Pocket Sized UTM Slot Tool - Degrees — Compass rose marked in degrees.
https://maptools.com/product/PocketSlots

A pocket sized tool with slot scales for 1:24,000, 1:25,000, and 1:50,000 scale maps. The 1:24,000 and 1:25,000 scales allow you to divide a 1km map grid with 10m precision. The 1:50,000 scale allows you to divide a 1km map grid with 20m precision. The tool also has a compass rose along its outside edge marked in degrees. This makes plotting or measuring a bearing a snap. The small size of this tool will allow you to keep it handy in your pocket. <br /><br />We also have this tool with a compass rose marked in mils or 90 degree quadrants, <a href="/product/PocketSlotsMils">PocketSlotsMils</a><a href="/product/PocketSlotsQuads">PocketSlotsQuads</a><br/><br/>A band of white ink around the edge of the tool makes reading the compass rose easier and also keeps the tool from “disappearing” when you place it on the map. There is also a lanyard hole in the upper left corner. <br /><br />Printed on plastic stock, the tool is about the thickness of a credit card. The ink is coated to protect it from abrasion.

### Pocket Sized UTM Slot Tool - Mils — Compass rose marked in mils.
https://maptools.com/product/PocketSlotsMils

A pocket sized tool with slot scales for 1:24,000, 1:25,000, and 1:50,000 scale maps. The 1:24,000 and 1:25,000 scales allow you to divide a 1km map grid with 10m precision. The 1:50,000 scale allows you to divide a 1km map grid with 20m precision. The tool also has a compass rose along its outside edge marked in mils. This makes plotting or measuring a bearing a snap. The small size of this tool will allow you to keep it handy in your pocket. <br /><br /> We also have this tool with a compass rose marked in degrees or 90 degree quadrants, <a href="/product/PocketSlots">PocketSlots</a><a href="/product/PocketQuads">PocketQuads</a><br/><br/> A band of white ink around the edge of the tool makes reading the compass rose easier and also keeps the tool from “disappearing” when you place it on the map. There is also a lanyard hole in the upper left corner. <br /><br /> Printed on plastic stock, the tool is about the thickness of a credit card. The ink is coated to protect it from abrasion.

### Pocket Sized UTM Slots for My Topo Air Photos
https://maptools.com/product/MyTopo-2

These pocket sized UTM tools are designed to be used with topographic maps and aerial photography printed by MyTopo's online map printing service. The tool includes the 3 scales used for aerial photography.<br /><br /> Don't forget to turn on the UTM Grid option when you order your maps.

### Pocket Sized UTM Slots for My Topo Maps
https://maptools.com/product/MyTopo-1

This pocket sized UTM tool is designed to be used with topographic maps printed by MyTopo's online map printing service. The tool includes the 4 scales offered for topographic maps. Don't forget to turn on the UTM Grid option when you order your maps.

### REDs Coordinate Scale and Protractor
  — Risk Estimate Distances for Common Mortar Rounds
https://maptools.com/product/REDs-1

<p>Risk Estimate Distances (REDs) take into account the bursting radius of particular munitions and the characteristics of the delivery system and associates this combination with a percentage for the probability of incapacitation of soldiers at a given range. The RED-combat (or MSD-training) is defined as the minimum distance friendly troops can approach the effects of friendly fires without suffering appreciable casualties of 0.1% or higher probability of incapacitation.</p> <p>This tool has concentric range rings for danger areas of mortar and artillery systems. Placing the crosshairs on a target allows maneuver units to see how close they can get to where rounds are impacting and still be safe. This allows fire supporters and ground commanders to plan fires (the term used for indirect systems like mortars, artillery, missiles and ordinance from aircraft) on the objective and ensure consistent fires on the enemy as friendly forces move on the battlefield. This is called echeloning of fires and a more detailed explanation can be found in FM 3-90.2.</p> <p>There are concentric range rings for standing posture REDs for 60mm, 81mm, 120mm mortars and 105mm and 155mm HE Howitzer rounds. There is a set of rings for 1:25,000 scale maps and another for 1:50,000 scale maps.</p> <p>The other aspects of the tool are an improved version of the Graphic Training Aid 5-2-12 Coordinate Scale and Protractor used by United States and NATO military forces around the world. By using a slot on one side of the tool for access to the map, the tool can be more compact than the traditional GTA tool. The 1:100,000 scale now spans 5km grid lines, making it much more usable. The overall dimensions of the tool have been reduced so that it is the size of a music CD, easily fitting into a pocket or any slot where you could store a CD.</p><br /> The inner protractor is marked in degrees and the outer protractor is in mils.<br /><br /> Our coordinate scales offer significant benefits over the standard issue GTA 5-2-12:<br /><ul> <li>The tool is printed on plastic stock about the thickness and stiffness of a credit card, with a protective coating. It's 33% thicker than the standard military issue version, so it's less likely to be bent or broken when you need to use it.</li><li>Rounded corners keep it from wearing holes in your pockets.</li><li>Larger 1:50,000 and 1:100,000 scale rulers for maps with wider grid spacing.</li><li>It's the size of a music CD, so it tucks away in more storage spaces.</li></ul> <h3>Instructions for using Risk Estimate Distance Rings</h3> <p>In order to use the Risk Estimate Distance tool, you must first determine whether you are using a 1/50,000 or 1/25,000 map and then use the corresponding tool on the protractor. Next, place the crosshairs at the center of that tool on wherever you want to target on the map. The tool provides different RED (sku,version,type,description) VALUES based on how far away the indirect fire weapon system is from the target. If the distance from the target the 105mm cannon you want to use is 1/3 of its total range capability, then use the 1/3 range half of the circle. If a 60mm mortar you want to use is firing from its maximum range, then use the max range quarter of the circle. Once you have placed the crosshairs on the target and identified which portion of the circle you want to use for your intended weapon system, the resulting circle will tell you the closest distance from the target you can approach while you are firing on it before incurring a 0.1% probability of incapacitation. You can use this tool to plan echeloning fires, identify trigger points, plan attack positions, and more. </p> <p>In the example shown in the product images above, a 1/25000 REDs tool has been placed on a 1:25,000 scale map at the red X indicating the hostile target. When the target is an area, make sure to position the center of the tool on the edge closest to the troop position you are evaluating. It may be necessary to rotate the tool to place the desired range marks in the area between the target and the point being evaluated. In the example, positions south of the green planning line, could be supported using a 155mm cannon firing at max range. Once troops are between the green and blue planning lines, only 60 and 81mm mortars can be used at max firing range. A 105mm cannon could be used at 2/3 firing range. Once troops are past the blue planning line, supporting fire must be based on actual troop locations. Troops at the point labeled A, could be supported by 60mm mortars at max range.</p>

### Reference Card - Declination & Compass Rose
https://maptools.com/product/Card_Dec

<ul> <li>360° Protractor / Compass Rose</li> <li>Cardinal Compass Points</li> <li>24 Hour Clock Face</li> <li>Sample declination diagrams for both east and west declination</li> <li>North definitions</li> <li>Formulas for converting between Grid or True North and Magnetic North</li> <li>Using Grid and True North on a map</li> <li>Declination changes over time</li> </ul>

### Reference Card - Inclinometer for Slope Angle
https://maptools.com/product/Card_Slope

<ul> <li>Measures slope angle in both degrees and percent</li> <li>Mark to cut slit for weighted thread (thread not included)</li> <li>Usage diagram</li> <li>Relative slab avalanche frequency</li> reference</li> <li>Height of an object measurement diagram and formula</li> <li>x - y reference diagram</li> <li>% slope formula</li> </ul

### Reference Card - Latitude Longitude
https://maptools.com/product/Card_LatLon

<h5>Latitude:</h5><ul><li>Earth diagram showing parallels of latitude, the equator, and the poles</li> <li>Measuring latitude with a map ruler</li> <li>One minute to one nautical mile relationship</li></ul> <h5>Longitude:</h5><ul><li>Earth diagram showing meridians of<br />longitude west and east of the prime meridian</li> <li>Measuring longitude with a map ruler</li> <li>Example lat/lon coordinates in two popular formats and their GPS “units” settings.</li></ul>

### Reference Card - Millimeter Grid
https://maptools.com/product/Card_mm

Millimeter grid card with white background on one side, black on the other. Useful for examining snow crystals, sand grains, soil characteristics, or small artifacts.

### Reference Card - Time, Speed, and Distance
https://maptools.com/product/Card_Dist

<ul> <li>Time / Speed / Distance formulas</li> <li>Time / Speed / Distance variables and units</li> <li>1:24,000 scale ruler to measure kilometers, marked at 10m interval</li> <li>1:24,000 scale ruler to measure miles,<br />marked at 0.01 mile interval</li> <li>Miles to Kilometers conversion scale</li> <li>Useful distance unit conversion factors</li> <li>Inches ruler, marked at 1/10th inch interval</li> <li>Millimeter ruler</li> </ul>

### Reference Card - UTM, MGRS, USNG
https://maptools.com/product/Card_UTM

Universal Transverse Mercator Coordinates Reference Card<br /><ul> <li>Sample GPS display</li> <li>1km grid diagram</li> <li>Example of dividing a 1km grid into 100m squares and determining UTM in either meters or kilometers</li> <li>Reminder that the Easting comes before the Northing Military Grid Reference System & US National Grid</li> <li>Example GPS display in UTM showing components of MGRS/USNG coordinates</li> <li>Example 100,000m square diagram</li> <li>Example using the “large” digits from<br />UTM coordinates on the map.</li> <li>Example MGRS/USNG coordinates. Both full and abbreviated coordinates shown with 100m and 10m precision</li> </ul>

### Round Military Coordinate Scale and Protractor — Large Print, Compass Rose in Degrees
https://maptools.com/product/RoundGTA

This tool is an improved version of the Graphic Training Aid 5-2-12 Coordinate Scale and Protractor used by United States and NATO military forces around the world. By using a slot on one side of the tool for access to the map, the tool can be more compact than the traditional GTA tool. The tool features several additional map scales, including 1:24,000, which is the most common topographic map scale found within the United States. The 1:100,000 scale now spans 5km grid lines, making it much more usable. Plus, the overall dimensions of the tool have been reduced so that it is the size of a music CD, easily fitting into a pocket or any slot where you could store a CD.<br /><br /> This tool has larger print numbers on both the compass rose and the coordinate scales. The inner protractor is marked in degrees.<br /><br /> Bands of white ink are printed under the compass rose. This makes reading the compass rose easier and also keeps the tool from "disappearing" when you place it on the map.<br /><br /> Our coordinate scales offer significant benefits over the standard issue GTA 5-2-12:<br /><ul> <li>The tool is printed on plastic stock with a protective coating. This makes it about the thickness and stiffness of a credit card. It’s 33% thicker than the standard military issue version, so it’s less likely to bent or broken when you need to use it.</li> <li>Rounded corners keep it from wearing holes in your pockets.</li> <li>Includes 1:24,000 scale for USGS 7.5 minute topographic maps.</li> <li>Larger 1:50,000 and 1:100,000 scale rulers for maps with wider grid spacing.</li> <li>Larger print type on both the scales and compass rose.</li> <li>It's the size of a music CD, so it tucks away in more storage spaces.</li></ul> <h4> Use the Round GTA to make a sun compass</h4> <p>David Canterbury, with the Pathfinder School, has a good video on how to make a Sun Compass, using our Round GTA tool. Check it out: <a href="https://youtu.be/bnmZh82oz9Y">https://youtu.be/bnmZh82oz9Y</a></p>

### Round Military Coordinate Scale and Protractor — Large Print, Compass Rose in 90 Degree Quadrants
https://maptools.com/product/RoundGTAQuads

This tool is an improved version of the Graphic Training Aid 5-2-12 Coordinate Scale and Protractor used by United States and NATO military forces around the world. By using a slot on one side of the tool for access to the map, the tool can be more compact than the traditional GTA tool. The tool features several additional map scales, including 1:24,000, which is the most common topographic map scale found within the United States. The 1:100,000 scale now spans 5km grid lines, making it much more usable. Plus, the overall dimensions of the tool have been reduced so that it is the size of a music CD, easily fitting into a pocket or any slot where you could store a CD.<br /><br /> This tool has larger print numbers on both the compass rose and the coordinate scales. The inner protractor is marked in 90 degree quadrants.<br /><br /> Bands of white ink are printed under the compass rose. This makes reading the compass rose easier and also keeps the tool from "disappearing" when you place it on the map.<br /><br /> Our coordinate scales offer significant benefits over the standard issue GTA 5-2-12:<br /><ul> <li>The tool is printed on plastic stock with a protective coating. This makes it about the thickness and stiffness of a credit card. It’s 33% thicker than the standard military issue version, so it’s less likely to bent or broken when you need to use it.</li> <li>Includes 1:24,000 scale for USGS 7.5 minute topographic maps.</li> <li>Larger 1:50,000 and 1:100,000 scale rulers for maps with wider grid spacing.</li> <li>Larger print type on both the scales and compass rose.</li> <li>It's the size of a music CD, so it tucks away in more storage spaces.</li></ul>

### Ruler for converting miles/km and feet/meters
https://maptools.com/product/RulerConv

<p>This ruler has two graphical scales to enable you to convert between miles and kilometers or feet and meters, without the need of any calculations. Numeric conversion factors are also listed for reference. Since this ruler doesn’t measure anything on the map, it is not tied to any particular map scale.</p>

### Ruler Set for Benchmark Road & Recreation Atlas-Alaska 1:285,000
https://maptools.com/product/RS-BM-AK

<p>This ruler set was designed to be used with the Benchmark Road &amp; Recreation Atlas for Alaska. It contains 9 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 30° to 38° on a map with a scale of 1:285,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The "landscape" pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just inside of the edges of the map, in a degrees, minutes and seconds format. The "recreation" and "regional" sections of the atlas do not have lat/lon markings and are printed with a different scale. These rulers can not be used on pages in those sections.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for Benchmark Road & Recreation Atlas-Arizona 1:285,000
https://maptools.com/product/RS-BM-AZ

<p>This ruler set was designed to be used with the Benchmark Road &amp; Recreation Atlas for Arizona. It contains 9 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 30° to 38° on a map with a scale of 1:285,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The "landscape" pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just inside of the edges of the map, in a degrees, minutes and seconds format. The "recreation" and "regional" sections of the atlas do not have lat/lon markings and are printed with a different scale. These rulers can not be used on pages in those sections.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for Benchmark Road & Recreation Atlas-California 1:300,000
https://maptools.com/product/RS-BM-CA

<p>This ruler set was designed to be used with the Benchmark Road &amp; Recreation Atlas for California. It contains 13 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 31° to 43° on a map with a scale of 1:300,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The "landscape" pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just inside of the edges of the map, in a degrees, minutes and seconds format. The "recreation" and "regional" sections of the atlas do not have lat/lon markings and are printed with a different scale. These rulers can not be used on pages in those sections.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for Benchmark Road & Recreation Atlas-Colorado 1:200,000
https://maptools.com/product/RS-BM-CO

<p>This ruler set was designed to be used with the Benchmark Road &amp; Recreation Atlas for Colorado. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 36° to 42° on a map with a scale of 1:200,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The "landscape" pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just inside of the edges of the map, in a degrees, minutes and seconds format. The "recreation" and "regional" sections of the atlas do not have lat/lon markings and are printed with a different scale. These rulers can not be used on pages in those sections.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for Benchmark Road & Recreation Atlas-Idaho 1:250,000
https://maptools.com/product/RS-BM-ID

<p>This ruler set was designed to be used with the Benchmark Road &amp; Recreation Atlas for Idaho. It contains 11 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 40° to 50° on a map with a scale of 1:250,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The "landscape" pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just inside of the edges of the map, in a degrees, minutes and seconds format. The "recreation" and "regional" sections of the atlas do not have lat/lon markings and are printed with a different scale. These rulers can not be used on pages in those sections.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for Benchmark Road & Recreation Atlas-Montana 1:250,000
https://maptools.com/product/RS-BM-MT

<p>This ruler set was designed to be used with the Benchmark Road &amp; Recreation Atlas for Montana. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 44° to 50° on a map with a scale of 1:250,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The "landscape" pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just inside of the edges of the map, in a degrees, minutes and seconds format. The "recreation" and "regional" sections of the atlas do not have lat/lon markings and are printed with a different scale. These rulers can not be used on pages in those sections.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for Benchmark Road & Recreation Atlas-Nevada 1:280,000
https://maptools.com/product/RS-BM-NV

<p>This ruler set was designed to be used with the Benchmark Road &amp; Recreation Atlas for Nevada. It contains 9 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 35° to 43° on a map with a scale of 1:280,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The "landscape" pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just inside of the edges of the map, in a degrees, minutes and seconds format. The "recreation" and "regional" sections of the atlas do not have lat/lon markings and are printed with a different scale. These rulers can not be used on pages in those sections.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for Benchmark Road & Recreation Atlas-New Mexico 1:285,000
https://maptools.com/product/RS-BM-NM

<p>This ruler set was designed to be used with the Benchmark Road &amp; Recreation Atlas for New Mexico. It contains 9 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 30° to 38° on a map with a scale of 1:285,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The "landscape" pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just inside of the edges of the map, in a degrees, minutes and seconds format. The "recreation" and "regional" sections of the atlas do not have lat/lon markings and are printed with a different scale. These rulers can not be used on pages in those sections.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for Benchmark Road & Recreation Atlas-Oregon 1:225,000
https://maptools.com/product/RS-BM-OR

<p>This ruler set was designed to be used with the Benchmark Road &amp; Recreation Atlas for Oregon. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 41° to 47° on a map with a scale of 1:225,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The "landscape" pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just inside of the edges of the map, in a degrees, minutes and seconds format. The "recreation" and "regional" sections of the atlas do not have lat/lon markings and are printed with a different scale. These rulers can not be used on pages in those sections.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for Benchmark Road & Recreation Atlas-Utah 1:250,000
https://maptools.com/product/RS-BM-UT

<p>This ruler set was designed to be used with the Benchmark Road &amp; Recreation Atlas for Utah. It contains 9 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 35° to 43° on a map with a scale of 1:250,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The "landscape" pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just inside of the edges of the map, in a degrees, minutes and seconds format. The "recreation" and "regional" sections of the atlas do not have lat/lon markings and are printed with a different scale. These rulers can not be used on pages in those sections.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for Benchmark Road & Recreation Atlas-Washington 1:200,000
https://maptools.com/product/RS-BM-WA

<p>This ruler set was designed to be used with the Benchmark Road &amp; Recreation Atlas for Washington. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 44° to 50° on a map with a scale of 1:200,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The "landscape" pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just inside of the edges of the map, in a degrees, minutes and seconds format. The "recreation" and "regional" sections of the atlas do not have lat/lon markings and are printed with a different scale. These rulers can not be used on pages in those sections.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for Benchmark Road & Recreation Atlas-Wyoming 1:250,000
https://maptools.com/product/RS-BM-WY

<p>This ruler set was designed to be used with the Benchmark Road &amp; Recreation Atlas for Wyoming. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 40° to 46° on a map with a scale of 1:250,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The "landscape" pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just inside of the edges of the map, in a degrees, minutes and seconds format. The "recreation" and "regional" sections of the atlas do not have lat/lon markings and are printed with a different scale. These rulers can not be used on pages in those sections.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for Benchmark™ Road & Recreation Atlases - Western States
https://maptools.com/product/RS-BM-all

<p>This ruler set was designed to be used with the Benchmark™ Road &amp; Recreation Atlases</p> <p>The set contains 6 different rulers covering the map scales used by Benchmark™.</p> <p>Unlike our ruler set for individual state atlases, there are not a separate longitude rulers that have been adjusted for latitude. Longitude will need to be measured with the ruler at an angle that spans the longitude grid spacing.</p> <p>The set also contains rulers for measuring statute miles and kilometers at each of the 6 map scales.</p><p>Some Benchmark™ atlases also include city or regional maps at scales other than the main atlas scale. Rulers for these scale may not be included in this set.</p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p><ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme Atlas & Gazetteer-Texas 1:260,000 Scale
https://maptools.com/product/RS-DL-TX-260

<p>This ruler set was designed to be used with the DeLorme Atlas &amp; Gazetteer for Texas. It contains 13 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 25° to 37° on a map with a scale of 1:260,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on Rite-In-The-Rain™ cardstock instead of plastic.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme Atlas & Gazetteer-Virginia 1:140,000 2018 ed.
https://maptools.com/product/RS-DL-VA-2018

<p>This ruler set was designed to be used with the DeLorme Atlas &amp; Gazetteer for Virginia (2018 ed.). It contains 5 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 36° to 40° on a map with a scale of 1:140,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on Rite-In-The-Rain™ cardstock instead of plastic.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme Atlas & Gazetteer-Virginia 1:150,000 2009 ed.
https://maptools.com/product/RS-DL-VA-2009

<p>This ruler set was designed to be used with the DeLorme Atlas &amp; Gazetteer for Virginia (2009 ed.). It contains 5 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 36° to 40° on a map with a scale of 1:150,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on Rite-In-The-Rain™ cardstock instead of plastic.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme Atlas & Gazetteer-West Virginia 1:150,000 Scale
https://maptools.com/product/RS-DL-WV-150

<p>This ruler set was designed to be used with the DeLorme Atlas &amp; Gazetteer for West Virginia 1:150,000 scale. (Older versions of the atlas are 1:160,000) It contains 5 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 37° to 41° on a map with a scale of 1:150,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on Rite-In-The-Rain™ cardstock instead of plastic.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme Atlas & Gazetteer-Wyoming 1:225,000
https://maptools.com/product/RS-DL-WY

<p>This ruler set was designed to be used with the DeLorme Atlas &amp; Gazetteer for Wyoming. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 40° to 46° on a map with a scale of 1:225,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on Rite-In-The-Rain™ cardstock instead of plastic.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer All 50 States
https://maptools.com/product/RS-DL-all

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteers</p> <p>The set contains 20 different rulers covering the map scales used by DeLorme®.</p> <p>Each ruler carries a longitude scale calibrated for the southernmost latitude at which its map scale is used. Toward the north of that scale's coverage the atlas's longitude grid narrows a little, so tilt the ruler a few degrees to match — much less than the full grid angle the previous version of this set required.</p> <p>The set also contains rulers for measuring statute miles and kilometers at each of the 20 map scales.</p><p>Some DeLorme® atlases also include city or regional maps at scales other than the main atlas scale. Rulers for these scale may not be included in this set.</p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Alabama 1:182,000
https://maptools.com/product/RS-DL-AL

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Alabama. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 30° to 36° on a map with a scale of 1:182,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Alaska 1:300,000
https://maptools.com/product/RS-DL-AK

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Alaska. It contains 23 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 50° to 72° on a map with a scale of 1:300,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Arizona 1:260,000
https://maptools.com/product/RS-DL-AZ

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Arizona. It contains 9 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 30° to 38° on a map with a scale of 1:260,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Arkansas 1:200,000
https://maptools.com/product/RS-DL-AR

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Arkansas. It contains 5 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 33° to 37° on a map with a scale of 1:200,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-California 1:200,000
https://maptools.com/product/RS-DL-CA

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for California. It contains 13 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 31° to 43° on a map with a scale of 1:200,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Colorado 1:320,000
https://maptools.com/product/RS-DL-CO

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Colorado. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 36° to 42° on a map with a scale of 1:320,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Connecticut & Rhode Island 1:65,000
https://maptools.com/product/RS-DL-CTRI

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Connecticut &amp; Rhode Island. It contains 5 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 39° to 43° on a map with a scale of 1:65,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Florida 1:126,000
https://maptools.com/product/RS-DL-FL-126

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Florida. It contains 9 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 24° to 32° on a map with a scale of 1:126,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Florida 1:150,000
https://maptools.com/product/RS-DL-FL

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Florida. It contains 9 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 24° to 32° on a map with a scale of 1:150,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Georgia 1:182,000
https://maptools.com/product/RS-DL-GA

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Georgia. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 30° to 36° on a map with a scale of 1:182,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Hawaii 1:84,000
https://maptools.com/product/RS-DL-HI

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Hawaii. It contains 13 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 17° to 29° on a map with a scale of 1:84,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Idaho 1:250,000
https://maptools.com/product/RS-DL-ID

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Idaho. It contains 11 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 40° to 50° on a map with a scale of 1:250,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Illinois 1:150,000
https://maptools.com/product/RS-DL-IL

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Illinois. It contains 9 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 35° to 43° on a map with a scale of 1:150,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Indiana 1:156,000
https://maptools.com/product/RS-DL-IN

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Indiana. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 36° to 42° on a map with a scale of 1:156,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Iowa 1:200,000
https://maptools.com/product/RS-DL-IA

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Iowa. It contains 5 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 40° to 44° on a map with a scale of 1:200,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Kansas 1:200,000
https://maptools.com/product/RS-DL-KS

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Kansas. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 35° to 41° on a map with a scale of 1:200,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Kentucky - 1:150,000 Scale
https://maptools.com/product/RS-DL-KY-150

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Kentucky (older 1:150,000 sacal maps). It contains 5 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 36° to 40° on a map with a scale of 1:150,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Kentucky 1:200,000
https://maptools.com/product/RS-DL-KY

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Kentucky. It contains 5 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 36° to 40° on a map with a scale of 1:200,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Louisiana 1:182,000
https://maptools.com/product/RS-DL-LA

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Louisiana. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 28° to 34° on a map with a scale of 1:182,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Maine 1:130,000 2022 edition
https://maptools.com/product/RS-DL-ME-2022

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Maine 2022 edition. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 42° to 48° on a map with a scale of 1:130,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their values just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Maine 1:135,000
https://maptools.com/product/RS-DL-ME

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Maine. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 42° to 48° on a map with a scale of 1:135,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Maryland & Delaware 1:100,000
https://maptools.com/product/RS-DL-MDDE

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Maryland &amp; Delaware. It contains 5 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 36° to 40° on a map with a scale of 1:100,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Massachusetts 1:80,000
https://maptools.com/product/RS-DL-MA

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Massachusetts. It contains 3 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 41° to 43° on a map with a scale of 1:80,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Michigan 1:160,000
https://maptools.com/product/RS-DL-MI

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Michigan. It contains 9 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 41° to 49° on a map with a scale of 1:160,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Minnesota 1:205,000
https://maptools.com/product/RS-DL-MN

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Minnesota. It contains 9 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 42° to 50° on a map with a scale of 1:205,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Mississippi 1:182,000
https://maptools.com/product/RS-DL-MS

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Mississippi. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 29° to 35° on a map with a scale of 1:182,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Missouri 1:200,000
https://maptools.com/product/RS-DL-MO

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Missouri. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 35° to 41° on a map with a scale of 1:200,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Montana 1:250,000
https://maptools.com/product/RS-DL-MT

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Montana. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 44° to 50° on a map with a scale of 1:250,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Nebraska 1:200,000
https://maptools.com/product/RS-DL-NE

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Nebraska. It contains 5 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 40° to 44° on a map with a scale of 1:200,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Nevada 1:250,000
https://maptools.com/product/RS-DL-NV

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Nevada. It contains 9 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 35° to 43° on a map with a scale of 1:250,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-New Hampshire & Vermont 1:100,000
https://maptools.com/product/RS-DL-NHVT

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for New Hampshire &amp; Vermont. It contains 5 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 42° to 46° on a map with a scale of 1:100,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-New Jersey 1:77,000
https://maptools.com/product/RS-DL-NJ

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for New Jersey. It contains 5 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 38° to 42° on a map with a scale of 1:77,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-New Mexico 1:300,000
https://maptools.com/product/RS-DL-NM

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for New Mexico. It contains 9 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 30° to 38° on a map with a scale of 1:300,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-New York 1:150,000
https://maptools.com/product/RS-DL-NY

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for New York. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 40° to 46° on a map with a scale of 1:150,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-North Carolina 1:160,000
https://maptools.com/product/RS-DL-NC

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for North Carolina. It contains 5 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 33° to 37° on a map with a scale of 1:160,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-North Dakota 1:200,000
https://maptools.com/product/RS-DL-ND

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for North Dakota. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 44° to 50° on a map with a scale of 1:200,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Ohio 1:160,000
https://maptools.com/product/RS-DL-OH

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Ohio. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 37° to 43° on a map with a scale of 1:160,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Oklahoma 1:200,000
https://maptools.com/product/RS-DL-OK

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Oklahoma. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 32° to 38° on a map with a scale of 1:200,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Oregon 1:320,000
https://maptools.com/product/RS-DL-OR

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Oregon. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 41° to 47° on a map with a scale of 1:320,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Pennsylvania 1:150,000
https://maptools.com/product/RS-DL-PA

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Pennsylvania. It contains 5 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 39° to 43° on a map with a scale of 1:150,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-South Carolina 1:150,000
https://maptools.com/product/RS-DL-SC

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for South Carolina. It contains 5 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 32° to 36° on a map with a scale of 1:150,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-South Dakota 1:200,000
https://maptools.com/product/RS-DL-SD

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for South Dakota. It contains 5 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 42° to 46° on a map with a scale of 1:200,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Tennessee 1:140,000
https://maptools.com/product/RS-DL-TN

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Tennessee. It contains 5 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 33° to 37° on a map with a scale of 1:140,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Texas 1:400,000
https://maptools.com/product/RS-DL-TX

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Texas. It contains 13 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 25° to 37° on a map with a scale of 1:400,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Utah 1:235,000
https://maptools.com/product/RS-DL-UT

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Utah. It contains 9 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 35° to 43° on a map with a scale of 1:235,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Virginia 1:150,000 2009 Ed.
https://maptools.com/product/RS-DL-VA

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Virginia. It contains 5 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 36° to 40° on a map with a scale of 1:150,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Washington 1:160,000
https://maptools.com/product/RS-DL-WA

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Washington. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 44° to 50° on a map with a scale of 1:160,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-West Virginia 1:160,000
https://maptools.com/product/RS-DL-WV

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for West Virginia. It contains 5 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 37° to 41° on a map with a scale of 1:160,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for DeLorme® Atlas & Gazetteer-Wisconsin 1:160,000
https://maptools.com/product/RS-DL-WI

<p>This ruler set was designed to be used with the DeLorme® Atlas &amp; Gazetteer for Wisconsin. It contains 7 ruler pairs for measuring latitude longitude coordinates at latitudes ranging from 42° to 48° on a map with a scale of 1:160,000. It also contains rulers for measuring statute miles and kilometers. </p> <p>The pages of the atlas have a printed lat/lon grid shown with thin black lines. The lines are marked with their (sku,version,type,description) VALUES just outside of the edges of the map, in a degrees, minutes and seconds format and in decimal degrees.</p> <p>Longitude rulers used north of their design parallel of latitude, will be too long to fit the grid. The ruler should be "close enough" up to about 1° north of the design latitude. As you move north, you may find the next ruler in the set is a closer fit. You can also use the ruler on a slight diagonal between the grid lines to compensate for the extra length.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Ruler Set for National Geographic Trails Illustrated Maps
https://maptools.com/product/RS-NGTI

<p>This ruler set was designed to be used with the National Geographic Trails Illustrated Map Series. It contains rulers for measuring statute miles and kilometers at the 35 different map scales used in the series.</p> <p>Most (all?) of the maps in the series have UTM grids printed on the maps. The kilometer edge of these rulers can be used to measure the easting and northing vales of a UTM coordinate.</p> <p>These rulers are somewhat different than our regular plastic rulers...</p> <ul> <li>They are printed on 10 mil plastic stock.</li> <li>They are 1.5 inches wide and 8.5 inches long.</li> </ul> <p>We make these rulers using our custom ruler printing process. If you have need of a map ruler that not in one of our sets, check out the <a href="/simpleRulerDesign">custom map ruler design page</a>.</p>

### Set of 6 Reference Cards
https://maptools.com/product/RefCardSet

<p>A set that contains one of each of our Reference Cards, and a Pocket Magnifier.</p> <p>The set is packages in a small zip to plastic bag.</p> <ul> <li>UTM, MGRS, USNG</li> <li>Declination & Compass Rose</li> <li>Latitude Longitude</li> <li>Time, Speed, and Distance</li> <li>Millimeter Grid</li> <li>Inclinometer for Slope Angle</li> </ul>

### Tom Harrison Map Series UTM Slots
https://maptools.com/product/UTM-TH

Tom Harrison's maps are the best full-color, shaded-relief topographic maps for hiking, backpacking, and mountain biking in Parks, Forests, and Wilderness Areas in California. All of his maps are gridded for UTM coordinates. The scales are unusual, and MapTools is pleased to offer a tool specifically designed for these maps.

### USFS Maps UTM Slots
https://maptools.com/product/UTM-FS

Recently revised Forest Service Maps now frequently include UTM coordinate references. Hooray!<br /><br />Be sure to check your map, as there are still lots of FS maps that only have lat/lon coordinate info on them.<br /><br /> Printed on sturdy plastic with a protective coating.

### USGS Topographic Map Symbols
https://maptools.com/product/TopoSymSheet

This is a handout I use in my navigation classes. This is a reprint of a four page full color reference for the map symbols used on USGS topographic maps. You can <a href="../../pdfs/instructors/TopoSymbols.pdf"> download the pdf for free</a>. We'll send you a copy with your order for free. Or, if you need a bunch for your class, we sell them for less than you could print them on your own printer. ISBN 0-607-96942-3

### USGS Topographic Map Symbols 25 Pack
https://maptools.com/product/TopoSymSheet-25pk

### Using your GPS with UTM Coordinates 4th Ed.
https://maptools.com/product/UTMGuide4

An 89-page instruction book packed full of information on the Universal Transverse Mercator (UTM) Map Coordinate System and a “pocket-sized” UTM Grid Overlay suitable for use with 1:24,000 scale, 7.5 minute USGS topographic maps.<br />This booklet is a great starting point for beginning GPS users and folks who want to learn about UTM/MGRS coordinates. With lots of illustrations and step-by-step instructions, readers can convert between map locations and UTM coordinates quickly!<br /><br />Includes a 1:24,000 scale “Pocket Sized” Grid Tool for use with 7.5 minute USGS topographic maps.

### UTM Corner Ruler -- Large Classroom Training Aid
https://maptools.com/product/CornerRuler-TA

<p>This is a large UTM Corner Ruler style tool intended for use in a classroom teaching situation. It is about 4 times the size of our regular tools. That means you can hold it up to the whiteboard to demonstrate how to use it, and you students can see it.</p> <p>I’ve put holes at three corners of the 1 kilometer rulers so that you can easily mark a grid on the whiteboard for your demo map. Just make dots at the corner of as many grids as you want, and then connect the dots with a straight edge and your whiteboard marker. Add some grid coordinate labels and you are ready to demo UTM coordinates.</p> <p>The actual scale of the tool works out to 1:6,369. Use that scale if you want to create a map image for printing on a large sheet of paper to use with the tool, using a service like CalTopo.com to create your pdf file. If you want to enlarge part of a 1:24,000 scale map, enlarge it by 377%. (24000 / 6369 * 100)</p> <p>We use the same scale for our UTM Grid style classroom training aid, so it’s easy to move students from the conceptually simple idea of the grid tool that just fits inside the grid, to the more complicated, but more precise, measurements they can make with a corner ruler style tool.</p> <p>The tool has a protractor on its outer perimeter so you can use it to teach students how to plot a compass bearing using a protractor. I usually teach plotting with a protractor, before I teach how to do it using their compass. The protractor has no moving parts. Just line it up with which ever north reference you are using, and make a mark at the edge at what ever bearing you are plotting. Finish by drawing in the line with a straight edge. There is a hole in the center of the protractor so you can demonstrate using a string to extend a bearing beyond the tool. (String is not included.)</p> <p>There is also a hole in the corner that you can use to hand the tool from a nail or peg, to keep it handy. I put a self adhesive backed hook on the edge on my whiteboard to hang my training aids from.</p> <p>Here is a link to a page that describes <a href="/large-training-aids">how to use our line of large teaching aid products.</a> </p> <p>This product pairs nicely with some of our other tools and instructional handouts.</p> <ul> <li><a href="/product/Map1-TA">Map for use with Large Classroom Training Aids</a> </li> <li><a href="/product/PocketCorners">Pocket Sized UTM Corner Rulers Tool</a> </li> <li><a href="/product/AdvCorner">Adventure Racing Corner Rulers Tool</a> </li> <li><a href="/product/UTMGuide3">Using your GPS with UTM Coordinates Booklet 3rd Ed.</a> </li> <li><a href="/product/Card_UTM">Reference Card - UTM, MGRS, USNG</a> </li> <li><a href="/product/GridsSheet">Locating Coordinate Grid Information on USGS Maps Handout and Practice Map</a> </li> <li><a href="/product/MilStyleInsert">UTM Tool Instruction Sheet</a> </li> </ul>

### UTM Corner Rulers Overlay - 7 Scales
https://maptools.com/product/UTMCorners

A corner ruler will allow for very precise measurements to be made within the existing map grid square. Each corner ruler has a small hole to allow for placing a mark on the map.

### UTM Grid -- Large Classroom Training Aid
https://maptools.com/product/UTMGrid-TA

<p>This is a large UTM Grid style tool intended for use in a classroom teaching situation. It is about 4 times the size of our regular tools. That means you can hold it up to the whiteboard to demonstrate how to use it, and you students can see it.</p> <p>I’ve put holes at the four corners of the 1 kilometer grid square so that you can easily mark a grid on the whiteboard for your demo map. Just make dots at the corner of as many grids as you want, and then connect the dots with a straight edge and your whiteboard marker. Add some grid coordinate labels and you are ready to demo UTM coordinates.</p> <p>The actual scale of the tool works out to 1:6,369. Use that scale if you want to create a map image for printing on a large sheet of paper to use with the tool, using a service like CalTopo.com to create your pdf file. If you want to enlarge part of a 1:24,000 scale map, enlarge it by 377%. (24000 / 6369 * 100)</p> <p>We use the same scale for our UTM Slot style classroom training aid, so it’s easy to move students from the conceptually simple idea of the grid tool that just fits inside the grid, to the more complicated, but more precise, measurements they can make with a slot style tool.</p> <p>The tool has a protractor on its outer perimeter so you can use it to teach students how to plot a compass bearing using a protractor. I usually teach plotting with a protractor, before I teach how to do it using their compass. The protractor has no moving parts. Just line it up with which ever north reference you are using, and make a mark at the edge at what ever bearing you are plotting. Finish by drawing in the line with a straight edge. There is a hole in the center of the protractor so you can demonstrate using a string to extend a bearing beyond the tool. (String is not included.)</p> <p>There is also a hole in the corner that you can use to hand the tool from a nail or peg, to keep it handy. I put a self adhesive backed hook on the edge on my whiteboard to hang my training aids from.</p> <p>Here is a link to a page that describes <a href="/large-training-aids">how to use our line of large teaching aid products.</a> </p> <p>This product pairs nicely with some of our other tools and instructional handouts.</p> <ul> <li><a href="/product/Map1-TA">Map for use with Large Classroom Training Aids</a> </li> <li><a href="/product/UTMGrid24">1:24,000 Scale Pocket Size UTM Grid Tool</a> </li> <li><a href="/product/UTMGrid25">1:25,000 Scale Pocket Size UTM Grid Tool</a> </li> <li><a href="/product/UTMGuide3">Using your GPS with UTM Coordinates Booklet 3rd Ed.</a> </li> <li><a href="/product/Card_UTM">Reference Card - UTM, MGRS, USNG</a> </li> <li><a href="/product/GridsSheet">Locating Coordinate Grid Information on USGS Maps Handout and Practice Map</a> </li> <li><a href="/product/MilStyleInsert">UTM Tool Instruction Sheet</a> </li> </ul>

### UTM Slot -- Large Classroom Training Aid
https://maptools.com/product/UTMSlot-TA

<p>I’ve put holes at the four corners of the 1 kilometer grid square so that you can easily mark a grid on the whiteboard for your demo map. Just make dots at the corner of as many grids as you want, and then connect the dots with a straight edge and your whiteboard marker. Add some grid coordinate labels and you are ready to demo UTM coordinates.</p> <p>The actual scale of the tool works out to 1:6,369. Use that scale if you want to create a map image for printing on a large sheet of paper to use with the tool, using a service like CalTopo.com to create your pdf file. If you want to enlarge part of a 1:24,000 scale map, enlarge it by 377%. (24000 / 6369 * 100)</p> <p>We use the same scale for our UTM Grid style classroom training aid, so it’s easy to move students from the conceptually simple idea of the grid tool that just fits inside the grid, to the more complicated, but more precise, measurements they can make with a slot style tool.</p> <p>The tool has a protractor on its outer perimeter so you can use it to teach students how to plot a compass bearing using a protractor. I usually teach plotting with a protractor, before I teach how to do it using their compass. The protractor has no moving parts. Just line it up with whichever north reference you are using, and make a mark at the edge at what ever bearing you are plotting. Finish by drawing in the line with a straight edge. There is a hole in the center of the protractor so you can demonstrate using a string to extend a bearing beyond the tool. (String is not included.)</p> <p>There is also a hole in the corner that you can use to hand the tool from a nail or peg, to keep it handy. I put a self adhesive backed hook on the edge on my whiteboard to hang my training aids from.</p> <p>Here is a link to a page that describes <a href="/large-training-aids">how to use our line of large teaching aid products.</a> </p> <p>This product pairs nicely with some of our other tools and instructional handouts.</p> <ul> <li><a href="/product/Map1-TA">Map for use with Large Classroom Training Aids</a> </li> <li><a href="/product/UTMSlot24">1:24,000 Pocket Sized Slot Tool</a> </li> <li><a href="/product/UTM-SC24">1:24,000 Credit Card Sized UTM Slot Tool</a> </li> <li><a href="/product/UTM-SC25">1:25,000 Credit Card Sized UTM Slot Tool</a> </li> <li><a href="/product/PocketSlots">Pocket Sized UTM Slot Tool - Degrees</a> </li> <li><a href="/product/UTMGuide3">Using your GPS with UTM Coordinates Booklet 3rd Ed.</a> </li> <li><a href="/product/Card_UTM">Reference Card - UTM, MGRS, USNG</a> </li> <li><a href="/product/GridsSheet">Locating Coordinate Grid Information on USGS Maps Handout and Practice Map</a> </li> <li><a href="/product/MilStyleInsert">UTM Tool Instruction Sheet</a> </li> </ul>

### UTM Slot Tool (14 Scales) — 14 Scales in a compact tool
https://maptools.com/product/UTMSlots

This tool combines 14 of the most common topographic map scales into a single tool about the size of a CD. The slot style tool gives easy access to the map for marking, while maintaining superior accuracy.

### UTM Slots for 1:31,680 1 inch = 1/2 mile — McKenzie Boundary Waters maps and Halfmile's PCT maps
https://maptools.com/product/UTM-MK

<p>The 1:31,680 scale represents a distance equivalence of 1 inch = 1/2 mile. When I created this tool, I had the <a href="http://www.bwcamaps.com/">McKenzie Boundary Waters maps</a> in mind. Since then I've discovered that <a href="http://www.pctmap.net/">Halfmile's pdf maps of the Pacific Crest Trail</a> also use this scale, have a 1km UTM grid on them, and are a great match with this tool.</p> <p>The Philmont Scout Ranch's sectional maps are also a good match with this tool.</p> McKenzie Maps of:<br /><ul> <li>The Boundary Water Canoe Area Wilderness of Minnesota, USA</li> <li>The Quetico Provincial Park of Ontario-Canada</li> <li>Isle Royale National Park</li> <li>Voyageurs National Park</li> <li>Superior Hiking Trail</li> <li>Superior National Forest</li> <li>The North Shore of Lake Superior</li> <li>The Apostle Islands on the South Shore and the Duluth/Superior Harbor</li> </ul>

### UTM Tool Instruction Sheet — Tools for working with UTM, MGRS and USNG coordinates
https://maptools.com/product/MilStyleInsert

This is a handout I use in my navigation classes. It is 4 pages of color info and illustrations using our tools to measure UTM, MGRS and USNG coordinates. It includes a small 1:50,000 scale practice map with 7 example problems. I originally designed it as a companion to our "military style" tools. Bu now days we send a copy with every order for free. You can <a href="../../pdfs/instructors/MilStyleInsert.pdf"> download the pdf for free</a>. Or, if you need a bunch for your class, we sell them for less than you could print them on your own printer.

## Guides & Information

### 100km Square Identifier — MGRS and USNG 100,000-meter Square Identification MGRS and USNG 100,000-meter Square Identifications are Different when Used with the NAD 27 Datum Both the MGRS and USNG systems default to the WGS84 datum.
https://maptools.com/tutorials/100km_square_id

MGRS and USNG 100,000-meter Square Identification MGRS and USNG 100,000-meter Square Identifications are Different when Used with the NAD 27 Datum Both the MGRS and USNG systems default to the WGS84 datum. They differ when used with the NAD 27 Datum. This is particularly important to users within the Continental Unites States, where many topographic maps produced by the United States Geologic Survey are referenced to the NAD 27 Datum. The MGRS System shifts the second letter of the 100,000-meter square identification by ten letters (excluding I and O). The USNG system does not make this letter shift, but does require that the datum be specified. The example coordinate we have been using would look like this when referenced to the NAD 27 Datum: MGRS: 10S GU 06832 44683 USNG: 10S GJ 06832 44683 (NAD 27) To learn more about Map Datums follow this link: Map Datums and why they are so important The letter shift also occurs in MGRS when working with other datum that use the Bessel 1841 and Clarke 1880 ellipsoids, which includes much of Africa, Japan, Korea, and Indonesia. When you are working with old maps and MGRS coordinates, be aware that occasional unusual letter adjustments have been used in the past. Find the 100,000-meter Square Identification on Your Map Most modern maps that are designed with MGRS or USNG will have a small box in the margin with the Grid Zone Designation and the 100,000-meter Square Identification. Map that span more than one 100,000m square will show a diagram with both square id's. Most USGS topographic maps printed before about 2014 will not have this information on them. Your GPS will determine the 100,000-meter Square Identification for Your Current Location A GPS receiver to show positions in MGRS or USNG formats will show the 100,000m square id as part of the coordinate. They will also show this for stored waypoints. A location can be converted from one position format to another by storing it as a waypoint in the GPS, changing the position format, and viewing the waypoint's location with the new format. Using the UTM Coordinate to Determine the 100,000-meter Square Identification The 100,000-meter square letters can be found given the UTM grid coordinates. #1 locate the zone number in the list at the top of the tables shown below. This identifies the set of designators in which the letters will be found. #2 Truncate the easting to 100,000 meters. Find the 100,000-meter easting grid line within the grid zone identified in the list at the top of the tables shown below. The easting lines are labeled below the table, from 200,000 meters to 800,000 meters within each zone. #3 Reduce the grid northing by multiples of 2,000,000 meters until the resulting value is between 0 and 2,000,000 meters. Then truncate the grid northing to 100,000 meters. Find the 100,000-meter northing grid line. The northing lines are labeled on the left side of the table. #4 The 100,000-meter square will be to the right and above the intersection of the lines found in the table. Let's try it with our example UTM coordinate10S 706832m E. 4344683m N. WGS84 datum Zone 10 directs us to set 4 The easting of 706,832 truncated to 100,000 meters would be 700,000. The northing of 4,344,683, gets 4,000,000 subtracted from it, giving 344,683. That gets truncated to 100,000 meters, for 300,000. The letter pair to the right and above 700,000m E and 300,000m N is GJ. So the MGRS and USNG coordinate would be 10S GJ 06832 44683.

### Abbreviated UTM Coordinates — Shorthand for UTM Coordinates Most land navigation activities focus on a very small portion of the globe at any one time.
https://maptools.com/tutorials/abbreviated

Shorthand for UTM Coordinates Most land navigation activities focus on a very small portion of the globe at any one time. Typically, the area of interest to an outdoorsman is less than 20 miles on a side. This focus on a small area allows us to abbreviate UTM coordinates. The zone information and the digits representing 1,000,000m, and 100,000m are dropped. The 1m, 10m and 100m digits are used only to the extent of accuracy desired. A GPS unit might read 10 S 0559741 4282182 Using a notation similar to the one found on a USGS topographic map, this would be written as: Zone 10 S 559741 mE. 4282182 mN. An abbreviated format for the same coordinates would look like: 59 82 Describes a 1000m by 1000m square. 597 821 Describes a 100m by 100m square. 5974 8218 Describes a 10m by 10m square. 59741 82182 Describes a 1m by 1m square. The 100m abbreviated format, 597 821, and the 10m abbreviated format, 5974 8218, are the most commonly used. Notice that the easting is reported first, followed by the northing. Remember the phrase "read right up" to help you remember to read the easting from left to right, followed by the northing from the bottom up. Also notice that when you abbreviate coordinates you should not do any rounding. 0559651 becomes 596 not 597. This ensures that your position is still within the reported square. As accuracy decreases, the square gets bigger.

### About MapTools — About MapTools I hope that you find the tools and information on these pages useful.
https://maptools.com/about

About MapTools I hope that you find the tools and information on these pages useful. The tools and the instructions that make up the MapTools website have been evolving since about 1993. My parents were both avid outdoor enthusiasts, back when the REI catalog was just a mimeographed sheet. So I grew up paddling kayaks, hiking the trails of Northern New Mexico and camping all over the West. In 1980, I joined the search and rescue team at the college where I was a student, Socorro Search & Rescue. Since then, I've been a member of various volunteer search and rescue teams as I've moved around the country. My land navigation skills continued to develop and I began teaching the skills to my fellow search and rescue team members. Starting in 1993, I began using the web as a method to distribute handouts and overlay graphics that I used in my classes. In 1995 MapTools.com was established as my domain name for my mapping stuff, moving the pages off of the local sar teams web page. In the early days the site was mostly a collection of useful pdf files that could be printed onto overhead transparency material. I found that many of the SAR folks that I work with needed some of these map tools to be readily available on a long-lasting material. The do-it-yourself nature of printing the pdf file onto overhead transparency stock was not meeting their needs. In 1997, I had the "1:24,000 Scale Pocket UTM Overlay" printed on 30mil plastic and made them available on the MapTools web page. The 1:24k tool has been very popular, with more than 5000 of them in use. The web pages and the tools themselves are all designed on an Apple Macintosh, using various tools by Adobe Systems. I've been both a Mac user and developer since the days of the very first Macs. I spent about 3 years working for Adobe, after they acquired a small software company I started while in graduate school. During the "internet boom" I worked for a small dot-com building a map based business directory that combined street maps with orthorectified aerial photography. These days I'm back to what I refer to as "self-unemployed." Doing a mixture of software development, GIS consulting, teaching classes, working on the MapTools web pages, SAR stuff, and hiking.

### Bulk Packaging Policy — Our Bulk Packaging Policy Most of our pocket sized tools ship with just the tool in a small zip top bag.
https://maptools.com/bulk-packaging-policy

Our Bulk Packaging Policy Most of our pocket sized tools ship with just the tool in a small zip top bag. Order several pocket sized tools, and they will likely all come in a single zip top bag. The goal being for you to get a single small bag to store your tools in. Our larger tools come stuck to a card with a description of the tool. With some of them the card is a folded piece with a small practice map inside. Our map rulers come in a vinyl pouch with an instruction sheet. When your order several different ruler scales, they will most likely be combined into a single pouch. Again the goal being for you to have a pouch to keep your rulers in. If it is obvious that you are ordering several sets of the same tools, I'll try to send enough bags and pouches to hold each set. Most of our customers that order larger quantities of our tools, don't want anything but the tool. Typically, when shipping quantities over the first price break quantity, I ship just the tools, with no packaging. I think these policies work for most folks. But if you have different needs in regard to how things get packaged, you should contact me to see if I can accommodate your needs.

### Choosing a Coordinate System — Selecting a Geographic Coordinate System Most GPS receivers come out of the box set to use latitude/longitude coordinates.
https://maptools.com/selecting_a_coordinate_system

Selecting a Geographic Coordinate System Most GPS receivers come out of the box set to use latitude/longitude coordinates. And many GPS users never consider that there may be other coordinate system that would better meet their needs. I would urge you to consider coordinate formats based on the Universal Transverse Mercator map projection and coordinate system. Many land based users will find them to be easy to use and well suited to their needs. But, as much as I like using UTM, there are some circumstances where lat/lon is a better choice. This page provides information to help you make the choice between using UTM based coordinates or lat/lon coordinates. When it comes to selecting tools for plotting and measuring coordinates, all of our tools that work with the UTM system also work with the other UTM based systems; USNG and MGRS. For specific information on the two coordinate systems, check out the tutorial pages... UTM Based coordinate systems UTM — Universal Transverse Mercator MGRS — Military Grid Reference System USNG — United States National Grid Latitude Longitude Lat/Lon – Using Latitude Longitude Coordinates Use the same system that your peers are using If you are working with other folks and passing map coordinates around, then you will want to use the same coordinate system and notations that they use. Unless of course you're convinced they should all change to something better, and you're willing to be the force behind the change. You will find that most aviation and maritime users are already using lat/lon coordinates. Use a system that works well with your maps If you are working with maps that cover more than 6 degrees of longitude or are 1:1,000,000 scale or less, you will probably want to use lat/lon coordinates. Small scale maps are often projected using a map projection that will result in UTM grids that are not square. Small scale UTM gridded maps need to use a projection where lines of longitude appear to be parallel, such as a Mercator projection. On larger scale maps the choice of coordinate system is often determined by the coordinate references that have been supplied by the mapmaker. USGS puts both lat/lon and UTM coordinates on all of their large scale maps. Many other mapmakers only provide lat/lon references. It is possible to add a UTM grid to a map that is only marked with lat/lon references. But it is a tedious process, so you might be better off just using lat/lon coordinates. Many maps have no coordinate references at all. You can add coordinate references by either comparing known features with another map that has coordinate information or by locating several know point in the field and "surveying" them with your GPS receiver. This is a difficult process, but at least you can choose what coordinate system to use. If you are using or considering buying computer based maps, check what coordinate systems are available in the software. Beware of "decorative" lat/lon references. Some mapmakers have provided lat/lon information that is approximate at best. Before GPS receivers were common place, it was rare that a casual map user would even notice coordinate references, much less care if they are accurate. The times have changed, but many maps haven't caught up yet. Use a system that easy to use If your using a large scale map, you have UTM coordinates information, and your peers haven't already made the decision for you, then UTM is likely to be your best bet. Some of the advantages of UTM coordinates include... Square grids East-West units of measure are the same as North-South units Decimal based, no fussing with minutes and seconds. Coordinates translate directly to distances on the ground. Coordinate precision is easily understood. No need to wonder what distance a tenth of a second of longitude represents. It's easy to abbreviate coordinates when working in a small area.

### Contact MapTools — Contact Us: If you have any questions regarding our products or services, please contact me.
https://maptools.com/contact

Contact Us: If you have any questions regarding our products or services, please contact me. I look forward to hearing from you. I am often away from the phone, please leave a message if you don't get me personally. Phone: Fax: 650.446.1430 E-mail: I get about 2000 spam emails a week, most of which get filtered out automatically. About 1 in 4000 of these end up being a message from a customer that should not have been filtered . To bypass my spam filters, please include one of the following words somewhere in the body of your email: UTM, MGRS, longitude, compass, coordinate Other support resources include: Frequently Asked Questions

### Cookie Policy — Cookies and Javascript Your shopping cart is empty!
https://maptools.com/cookies

Cookies and Javascript Your shopping cart is empty! If you reached this page, after adding an item to your shopping cart, it's because your web browser did not accept the cookie we asked it to store to allow us to identify your shopping cart. You can enable cookies and try again. Or you can call us on the phone to place your order. Cookies and Javascript Visiting MapTools' website with your browser settings adjusted to accept cookies tells us that you want to use MapTools' products and services, and that you consent to our use of cookies to provide them to you as described in this notice. See below for information on how to modify the settings in your browser to notify you when you receive a new cookie, or to disable cookies altogether. Cookies and How We Use Them Cookies are alphanumeric identifiers that we transfer to your computer's hard drive through your web browser to enable our systems to recognize your browser and to provide services. For information on the controllers of your personal information, see our Privacy Policy. We use cookies for just one thing: To keep track of the session to identify your shopping cart while you are shopping and checking out. Cookies and Browser Settings The Help menu on the menu bar of most browsers will tell you how to prevent your browser from accepting new cookies, how to have the browser notify you when you receive a new cookie, and how to disable cookies altogether. Javascript Many of the pages on our site also use a bit of Javascript to provide you a better overall browsing experience. There is only one web programmer here at MapTools, and there just is not time in the day to create an alternate version of the site that does not require Javascript.

### Coordinate Converter
https://maptools.com/coordinate-converter

### Corners vs Slots — Corner Ruler v.s.
https://maptools.com/corners_vs_slots

Corner Ruler v.s. Slot Style Tools I think our "Slot Style" tools are a significant design improvement over the more traditional Corner Ruler / Roamer tool style. The Corner Ruler is like the IBM of the coordinate plotting world. Traditional, maybe even old-fashioned. But you can't go wrong with IBM. The biggest improvement with the Slot Style tool is that one edge of the tool is always placed one a UTM grid line. This simple step ensures that the tool is always square with the grid. With the Corner Ruler you have to eyeball the tool to be square with the grid. The second biggie it the ability to quickly verify that the tool you are using actually fits the grid. A quick glance up to the top on the northing scale on a slot tool should show the end of the scale aligned with the top of the grid square. Sure you can check this with the Corner Ruler, but it requires a separate placement of the tool on the grid, and this step is usually omitted. When your using a tool with multiple scales on if it is important to do the quick check to make sure you are using the right scale. Plus in these modern times, when the map we are using has likely been custom printed from some sort of digital data source, it's important to check that the map is really printed at the scale you expect it to be. Are there any downsides to the Slot Style tool? Aside from bucking tradition, there is only one downside that I have experienced. The Slot Style tools are not quite as rugged as the Corner Ruler Tools. This is because the slot is a bigger hole in the plastic than the hole at the corner of the rulers on a Roamer. That said, I have not had any reports of the slot tools failing in normal field use.

### Custom Made Tools — Custom Made Tools Custom Map Rulers Build your own customized ruler for any map scale.
https://maptools.com/custom

Custom Made Tools Custom Map Rulers Build your own customized ruler for any map scale. For full control over every edge, try the Advanced Ruler Designer where you can choose any graticule type at any scale for each of the four edges. You can create a map ruler for any map scale you may encounter. The four long edges of the ruler will have scales for measuring: Latitude in Degrees, Minutes and Seconds, or Degrees and Decimal Minutes, or Decimal Degrees Longitude for a specified latitude. No more need to use the latitude scale at an angle! Miles statute or nautical, and divided into decimal or fractional subdivisions. Kilometers The rulers we print and send you will be somewhat different from our stock rulers. It will be printed on a 10 mil polyester stock. Waterproof, weatherproof, and tear proof, but a bit thinner than our stock rulers. It will be an inch and a half wide instead of one inch. This makes room for you to add a personalized label on each side. Coming next (hopefully soon) I'm working to make the customized Map Rulers even more customizable. You'll be able to make rulers with multiple map scales on a single ruler, and I'll add a few more units to measure in, probably feet, yards, chains, and paces. Shortly after that is working, I'm hopeful to be able to make slope measuring tools for scales and contour intervals of your choosing. Still in the planning stages Is a "corner of the page" style measuring tool somewhat similar to our Mini Corner Tools. These should allow you to measure UTM, MGRS, USNG, or any other square metric coordinate grid for a map scale of your choosing. Custom Tool on clear plastic stock Currently, we do not have the capability to print on clear plastic stock in house. Our clear plastic tools get printed on large lithographic presses with specialized inks. We typically have jobs printed on large sheets with many tools on them. The minimum cost-effective press runs at 1000 of these large sheets. If you need 1000 or more custom tools, we cn work with you to get it done. If you just need a few custom tools on clear plastic, wo do not currently have the ability to do that. I do have my eye on some printing equipment that would allow us to print even a single tool at a reasonable cost. Alas, it's a $50k machine, and I'm having trouble making a good business case to buy it.

### Dealer List — Resellers of MapTools Products Please note, that most resellers stock only the most common scales of our tools.
https://maptools.com/dealers

Resellers of MapTools Products Please note, that most resellers stock only the most common scales of our tools. It's best to contact them in advance to make sure they have what you are interested in. Online Resellers of MapTools Products Retail Stores by State/Country AL | AK | AZ | AR | CA | CO | CT | DE | DC | FL | GA | HI | ID | IL | IN | IA | KS | KY | LA | ME | MD MA | MI | MN | MS | MO | MT | NE | NV | NH | NJ | NM | NY | NC | ND | OH | OK | OR | PA | RI | SC SD | TN | TX | UT | VT | VA | WA | WV | WI | WY Canada | Costa Rica | South East Asia Online Resellers of MapTools Products www.amazon.com www.argear.com backpackinglight.com/ www.bradleyssurplus.com www.cgsmule.com www.minerox.com www.searchgear.com www.summithut.com www.trailteka.com ALABAMA ALASKA Alaska Natural History Association 750 West Second Avenue, Suite 100 Anchorage, AK 99501 866.257.2757 akgeo.org ARIZONA Summit Hut 605 E. Wetmore Rd. at 1st Ave. Tucson, AZ 85705 520.888.1000 Summit Hut 5045 E. Speedway Tucson, AZ 85712 520.325.1554 800.499.8696 www.summithut.com ARKANSAS Uncle Sam's Safari Outfitters 1494 N. College Fayetteville, AR 72703 479.442.0990 www.unclesams.com CALIFORNIA Search Gear 9235 Chesapeake Dr #G San Diego, CA 92123 800.474.2612 www.searchgear.com COLORADO Mac Van Maps 1045 B Garden of the Gods Rd. Colorado Springs, CO 80907 800.473.6277 www.macvanmaps.com CONNECTICUT DELAWARE DISTRICT OF COLUMBIA FLORIDA Map and Globe Store 2884 S. Orlando Dr. Sanford, FL 32773 407.898.0757 GEORGIA HAWAII IDAHO North Idaho Blueprint 1923 N 4th Suite 105 Coeur D'Alene, ID 83814 208.664.4930 Idaho Blueprint & Supply Co. 619 Main Street Boise, ID 83702 208.344.787 ILLINOIS INDIANA Odyssey Map Store 902 N. Delaware Indianapolis, IN 46202 800.972.1388 IOWA KANSAS KENTUCKY LOUISIANA MAINE MARYLAND MASSACHUSETTS MICHIGAN MINNESOTA MISSISSIPPI MISSOURI Uncle Sam's Safari Outfitters St. Louis, MO www.unclesams.com Uncle Sam's Safari Outfitters St. Peters, MO www.unclesams.com MONTANA Missoula Blueprint Co. Inc. 1613 South Avenue West Missoula, MT 59801 866.741.9223 Blend's Copy Shop 509 First Ave. North Great Falls, MT 59401 406.454.3466 NEBRASKA NEVADA Gotta Getta Map 1566 Western Ave. Las Vegas, NV, 89102 702.678.6277 NEW HAMPSHIRE NEW JERSEY NEW MEXICO Holman's 6201 Jefferson St, NE Albuquerque, NM 87109 800.545.0932 www.holmans.com NEW YORK Bradley's Military 26444 US RT. 11 Evans Mills, NY 13637 1-800-503-4954 www.bradleyssurplus.com NORTH CAROLINA NORTH DAKOTA OHIO OKLAHOMA OREGON Jobe Wholesale 1618 SW Veterans Way Redmond, OR 97756 541.749.2122 www.jobewholesale.com Pittmon Map Company 825 SE Hawthorne Blvd. Portland, OR 97214 503.233.2207 PENNSYLVANIA RHODE ISLAND SOUTH CAROLINA SOUTH DAKOTA TENNESSEE TEXAS UTAH VERMONT VIRGINIA SAR GEAR PLUS 14240 Sullyfield Circle, Suite N Chantilly, VA 20151 703-449-5438 www.novaoutfitters.com TrailTeka Gear & Archery 42029 LAMZ PL Leesburg, VA 20176 571-252-9142 www.trailteka.com WASHINGTON WEST VIRGINIA WISCONSIN Milwaukee Map Service, Inc. 959 North Mayfair Road Milwaukee, WI 53226 414/774-1300 milwaukeemap.com WYOMING Mountain Sports 543 South Center Casper, WY 82601 307.266.1136 www.wyomap.com Canada Chaltrek 404 Balmoral Street Thunder Bay, On P7C 5G8 807.577.8848 www.chaltrek.com Costa Rica Costa Rica Safety Fire & Rescue Heredia, Mercedes Norte Costa Rica 40102 Phone: +506-8735-4123 jorgeulloa@safire-int.com www.safire-int.com South East Asia South East Asia Map Reading Land Navigation Club (MAPLAND) Lot 3317 Kg Peraku Seberang Kuala Pilah 72000 Negeri Sembilan Malaysia Phone: +6012 904 2437 maplandnavi@gmail.com

### Forward and Back Bearings — Understanding forward and back bearings Understanding forward and back bearings Taking a forward bearing.
https://maptools.com/tutorials/plotting/forward-and-back-bearings

Understanding forward and back bearings Understanding forward and back bearings Taking a forward bearing. The first compass bearing we need to take at the lake is from our unknown location to our cabin on the far shore. The bearing we end up with represents the angle between a line from Magnetic North to our location, and a line from our location to the cabin. This bearing is a "forward bearing." But when we go to plot this bearing on our map, we can't plot the angle from our current location since that is what we are trying to find. Instead, we plot a bearing from the cabin, as if someone there took a bearing "looking BACK towards our location." This would be called a "back bearing" and will be 180° different from our "forward bearing." How to determine a back bearing One technique is to do the math. Add or subtract 180° from you forward bearing to get your back bearing. You want the result to fall between 0° and 360°, so if the forward bearing is less than 180°, add 180° to it, and if it's greater than 180°, subtract 180°. Calculating a back bearing. If you are bad with math in your head, the "200/20" trick might help you. When your bearing is less than 180°, add 200° and then subtract 20° (same as adding 180°). When your bearing is greater than 180°, subtract 200° and then add 20° (same as subtracting 180°). Forward and back bearings as seen through a sighting compass. There are also lots of tricks that avoid doing the arithmetic entirely... Most sighting compasses show the back bearing in a smaller font size above or below the forward bearing. When you are taking a bearing with a baseplate compass, and you want a back bearing instead of a forward bearing, box the compass needle with the south end where the north end would usually be. The resulting bearing will be 180° different. Aligning North needle with South for a back bearing. When you are plotting your bearing, start by plotting a short segment of the forward bearing. When you extend the line, extend it in the opposite direction. Plotting a back bearing with a protractor. Next get straight in your head, where you will be plotting the bearing from on the map, and whether you will be plotting a forward bearing or a back bearing. You will always be starting to plot your bearing from the known location and then extending your line towards the unknown location. If you took the bearing from the known location, you will be plotting a forward bearing, starting at the known location. If you took the bearing from the unknown location, you will be plotting a back bearing, starting at the known location.

### Free Area Calculation Tools — Tools for Estimating the Size of an Area Full Sheet w/ conversions for miles, kilometers, acres.
https://maptools.com/free_tools/area_tools

Tools for Estimating the Size of an Area Full Sheet w/ conversions for miles, kilometers, acres. Resolution to 0.01 sq. mi at 1:24,000 scale. You'll need a calculator with this one. Pocket Sized Tools 1:24,000 Square Miles (1 sq. mi., resolution to 1/100th of a sq. mi.) 1:24,000 Kilometers (1 sq. km, resolution to 1/100th of a sq. km, also good as a UTM Grid) 1:24,000 Acres ( ~3.5" X 3.5", resolution to 10 acres)

### Free Latitude/Longitude Tools — Latitude Longitude Tools How to use Latitude Longitude Coordinates Latitude Longitude Rulers -- Multiple Scales Minutes and 10ths of minutes.
https://maptools.com/free_tools/lat_lon_tools

Latitude Longitude Tools How to use Latitude Longitude Coordinates Latitude Longitude Rulers -- Multiple Scales Minutes and 10ths of minutes. 1:24,000 Scale Latitude Longitude Ruler 2.5 minutes Minutes and 10ths of minutes 0 to 2.5 minute and 0.5 to 3 minute scales

### Free PDF Tools — Useful Map Tools for Downloading These pages contain freely downloadable grids, roamers, and rulers for plotting UTM / MGRS and latitude longitude coordinates.
https://maptools.com/free_tools

Useful Map Tools for Downloading These pages contain freely downloadable grids, roamers, and rulers for plotting UTM / MGRS and latitude longitude coordinates. You'll also find scale bars, area estimators, and compass roses here. If you work with maps very often then you will probably find some of these tools useful. The tools you see here have evolved from doing ground search and rescue operations in the United States. Some are small pocket sized tools and others are more suited to working at a desk or table. My interest in maps and related tools evolved from my work as search and rescue volunteer. I am interested in teaching people how to make the best use of their maps, compass, altimeter, and GPS unit. Part of that teaching process involves having some simple tools available. This website has evolved to fill that need. These tools are copyrighted. However, permission is granted to make and distribute copies on a not for profit basis. If you want to resell these tools, please check with me first! All the tools on this page can be downloaded in Adobe Acrobat (pdf) format. Adobe Acrobat is available for free, and runs on many different platforms. See below for information on downloading Acrobat Readers from Adobe. The pdf format should preserve the size of the overlay when you print them. But, you should double-check that your final printed version is the proper size! Some folks have reported problems with the smallest type on some of the tools being impossible to read. The best printed results will come from a high resolution Postscript printer. How to make overlays from these files To produce usable overlays you need to print directly onto or copy onto clear transparency film. Toner based printers and copiers will produce overlays that are prone to having the toner scratched off. Some folks have reported success laminating the transparency film to protect the image. The smaller overlays are available as one per page or with as many as will fit on a page. The clear stuff is expensive, so we put as many overlays as we can on each sheet. Some of these tools are for sale printed on sturdy plastic cards Many people find that overlays copied onto transparency fill are too flimsy; the toner wears off quickly under field conditions. Other folks don't have the stuff to print a nice crisp copy of the PDF files. To find out which tools are available visit the Map Tools Products page. If the scale you need isn't here, follow these instructions to create your own scale These tools were designed using Adobe Illustrator on a Macintosh. The PDF files can be opened and edited in Illustrator running either on a Mac or Windows platform. Maps come in all different scales. We have tried to include tools that work with the scales we use most frequently in ground search and rescue work here in the US. You may find that you need other scales. To scale an existing map tool to a different scale you should select a tool that is close to the scale you need, and then determine how much to scale it by. For example to turn a tool intended for a 1:24,000 scale map into one that would work with a 1:25,000 scale map. 24,000 / 25,000 * 100 = 96% You can use Adobe Illustrator, the Acrobat Reader, your printer software, or a photocopier to print at 96% of original scale. Always double-check your results against the map to make sure you get the correct results. to view and print these PDF files. Coordinate Converter (UTM, MGRS, USNG, Lat/Lon) UTM Coordinate Tools Estimating the size of an area Scales & Rules Latitude & Longitude Tools Protractors & Compass Roses

### Free Protractors and Compass Roses — Compass Roses Round Compass Rose Round Compass Rose Rotated for 17 degree East declination Square Compass Rose
https://maptools.com/free_tools/protractors

Compass Roses Round Compass Rose Round Compass Rose Rotated for 17 degree East declination Square Compass Rose

### Free Scale Rulers — Scales and Rules 1:24,000 Scale -- Miles, fractions of miles, feet, kilometers 1:24,000 Scale -- USGS Style -- Miles, feet, kilometers 1:25,000 Scale -- USGS Style -- Miles, feet, kilometers
https://maptools.com/free_tools/scale_rulers

Scales and Rules 1:24,000 Scale -- Miles, fractions of miles, feet, kilometers 1:24,000 Scale -- USGS Style -- Miles, feet, kilometers 1:25,000 Scale -- USGS Style -- Miles, feet, kilometers

### Free Stuff Information — Free Stuff
https://maptools.com/free-stuff

Free Stuff

### Free UTM Tools — UTM Coordinate Tools How to Use UTM, MGRS, and USNG Coordinates "Pocket Sized" 1:24,000 scale UTM Grid Overlay Tool The "pocket sized" tool contains.
https://maptools.com/free_tools/utm_tools

UTM Coordinate Tools How to Use UTM, MGRS, and USNG Coordinates "Pocket Sized" 1:24,000 scale UTM Grid Overlay Tool The "pocket sized" tool contains. 100 m. UTM Grid ReaderProtractor and straightedge for plotting azimuths I hand these out when I'm teaching students to work with UTM coordinates. Download this UTM Tool in PDF format... "Pocket Sized" 1:24,000 UTM Gird Overlay Purchase a "Pocket Sized" 1:24,000 UTM Grid Overlay Tool. UTM Grids The UTM grid overlays are useful to interpolate one decimal place beyond the grid interval on the map. For example on a 1:24,000 scale USGS topo map the UTM grid lines are 1000m apart. The overlay will show 100m increments. Grids like this work best for determining the coordinates of a mark on the map. To plot a point onto your map use a UTM Box tool that is open in the center. Download UTM Grids in PDF format... 1:24,000 1:25,000 1:50,000 1:62,000 1:100,000 1:125,000 1:250,000 UTM Corner Rulers Download UTM Corner Rulers in PDF format...UTM Corner Ruler Overlay Purchase a UTM Corner Rulers Overlay.

### Frequently Asked Questions — General Questions Questions about geographic coordinate systems What is UPS?
https://maptools.com/frequent_questions

General Questions Questions about geographic coordinate systems What is UPS? Is the WGS84 datum more accurate than NAD27? What are the distances represented by a minute of latitude and longitude? How do I calculate the distance between two points? Is the UTM system based on True North or Magnetic North? Is UTM is another name for MGRS? How can I convert between different datums? What is the latitude longitude of...? Questions about GPS selection, setup and use What kind of accuracy can I expect from my GPS? My GPS readings are consistently in the wrong position. What am I doing wrong? Which lat/lon format should I use? What is the User UTM Grid setting used for? Do I use UTM/UPS or User UTM Grid? How do I set my GPS receiver to use UTM? I'm very bad at directions and maps, will a GPS help me? Can you recommend a good GPS? MapTools and our products Free downloadable tools When I print one of your pdf map tools, it is the wrong size or will not print. What can I do? Can you provide a free tool like...? Web tutorials and exercises I put the coordinates for your sample problems into my topo map program, and they are out in the middle of the ocean! What am I doing wrong? I'm getting the wrong answers on the UTM sample problem, any ideas what I might be doing wrong? Using our products Is the information in the UTM booklet the same as the information on the web page? The UTM grid I have doesn't fit the grid on my map. What's wrong? Can I set the declination on a Brunton 54LU compass? The lat/lon ruler does not fit the lat/lon grid on my map. Why not? How durable are your tools? Will the ink wear off? Do you have a tool for this scale? Purchasing our products Will you accept government credit cards or purchase orders? Do you sell maps? Can I shop in person at your retail store? Do you have a dealer in ...? I don't trust the Internet with my credit card info. Can I place an order by phone? How can I purchase your products? About your order Where is my order? I need my order by a specific date. Will it get here in time? My order should have arrived by now... Did you ship my order? I didn't get a confirmation email. How are orders shipped? When are orders shipped? General Questions Questions about geographic coordinate systems What is UPS? UPS or Universal Polar Stereographic is used in the polar regions north of 84 deg. and south of 80 deg. It is based on a polar stereographic projection tangent at the pole. (Picture a radar scope centered on the North Pole.) From a users prospective it's still a square grid measured in meters. Should you end up in the poles, you'll find using UPS seems very much like using UTM. Setting your Garmin to display UTM/UPS is what you want to do. It will switch between the UTM and UPS regions should you happen to wander into the polar realms. Some of the reasons I like to do my own declination correction... No sighting compass can be adjusted for declination. I like using a sighting compass. There is no need to check my compass to see if it is adjusted correctly. It always gives me a magnetic bearing. A mis-adjusted compass give a bearing related to some random number. Hard to go back and correct any past data if you don't know what the mis adjustment was. This is a bigger problem with the Brunton compasses where the adjustment is a friction fit. Once the compass has seen some wear, there tend to adjust on their own. Because I think about declination every time I move a bearing between my compass and my map, I am more likely to have thought about what the current declination is for my current location, and I'm more likely to remember what declination is and how it works. I run across way too many people that have either forgotten how and why they adjusted their compass, or worse they had someone else do it for them. They don't understand declination. Sometimes they can't tell me if their compass bearing is relative to magnetic, true or grid north. The often have an incorrect declination setting for their current location. The downside of my choice is that I have to think and do some simple addition or subtraction every time I move a bearing between map and compass. I have talked with some extreme adventure racers that feel they are operating so close to the edge of physical and mental exhaustion, that they have no business doing any thinking and want their compass to do the correction for them. Is the WGS84 datum more accurate than NAD27? It is a false assumption that a coordinate value based on the 1927 North American Datum is less accurate than one based on NAD 83 or WGS 84. The coordinates for the same location are different. But given that the datum of the coordinate matches the datum used on the map, you will see no difference in the physical location. By way of an analogy, imagine that a mapmaker had decided to express all "coordinates" on his map as the distance from the tip of the Washington Monument and another mapmaker had decided to use the top of the empire state building. Their "coordinates" for a given location would be different, but each map would still be an accurate representation of the area. NAD 83 and WGS 84 are probably a better mathematical approximation of the shape of the earth than is NAD 27. If you wanted to do accurate calculations of distances and directions spanning large portions of the globe this might make a difference. For the everyday GPS user using a handful of topo maps the important thing to do is to match the datum set in the GPS with the datum the map uses. Using the wrong datum can result in position errors of hundreds of meters. What are the distances represented by a minute of latitude and longitude? If you assume that the world is a sphere, then the distance between a degree of latitude (N-S) is constant where ever you are on the globe. The distance between a degree of longitude (E-W) varies from the equator to the poles. It is the same as the distance between a degree of latitude at the equator, but is zero at the poles. A very rough calculation is that longitude distance = latitude distance X cos(latitude)so if a minute latitude is 1.15 statute miles then at 38 deg 15 mins (38.25 deg) it would be1.15 X cos(38.25) = 0.9031 statute miles and at 38 deg 16 mins (38.266 deg) it would be1.15 X cos(38.266) = 0.9029 statute miles a difference of about a foot. Of course since the world is really an ellipsoid, the actual calculations are more involved. The cosine approximation works well for large scale maps covering a small portion of the earth (like a 1:24,000 topo for example) How do I calculate the distance between two points? If you put them into your GPS as waypoints/landmarks and add them to a route, your GPS will calculate the distance for you. Button pushing details are different for each GPS model, so that is left as an exercise for the reader. If you have the points in UTM, and they are close enough together to ignore the curvature of the earth, you can work with them like XY Cartesian coordinates. The old Pythagorean Theorem will let you calculate the distance like so distance = sqrt( (X1-X2)**2 + (Y1-Y2)**2 ) Do a Google search on Pythagorean Theorem for prettier equations and pictures. Is the UTM system based on True North or Magnetic North? The grid line at the center of a zone, is the only one that is aligned with true north. The UTM grid lines are aligned with true north at the center of each utm zone, which would have an easting value of 500 km. As you move away from the central meridian, grid north, will vary a bit from true north. Most USGS topo maps will show the value for grid north (labeled GN) on their declination diagram. Usually it's less than a degree off of true north, and many folks ignore the difference and use the UTM grid lines as true north reference for plotting compass bearings. Is UTM is another name for MGRS? MGRS is just a special format for describing UTM coordinates. So the simple answer is that they are the same coordinate system. UTM coordinates are specified as Zone Number, Meters East (the easting), and Meters North (the northing). MGRS uses a Zone, A 2-letter code to indicate a 100km square, and an easting and northing value. Then the numeric easting and northing are abbreviated. See this link for details. The Zones are the same between the two systems, and the MGRS easting and northing values directly correspond to digits within the UTM easting and northings. How can I convert between different datums? You have several options... Here is a web site that will do it for you: http://jeeep.com/details/coord/ You can find software to do it using your computer. The best solution if you have lots of points to convert. You can use you GPS unit:Store the coordinates as a waypoint or landmark, switch the GPS to the desired coordinate system/datum, and recall the stored position. What is the latitude longitude of...? You should consult the USGS Geographic Names Information System (GNIS) at http://geonames.usgs.gov/ Remember that a lat/lon coordinate defines a point on the earth. How you decide what point to use for something large like a city is up for interpretation, which is to say their may be many correct answers. Questions about GPS selection, setup and use What kind of accuracy can I expect from my GPS? 10 - 20 meters (30 - 60 ft.) is typical, but there are a lot of variables. You should learn to check the GPS receiver's estimated position error value. Depending on the amount of sky visible, the configuration GPS satellites overhead and numerous other factors your accuracy at any given time could be much worse. (I've seen EPEs as high as 900m) With a WAAS capable receiver and a WAAS satellite in view you may get accuracies as good as a few meters. My GPS readings are consistently in the wrong position. What am I doing wrong? This is usually a datum problem. Make sure that the datum used by the map is the same as the datum set in the GPS. In the continental US this will usually be either NAD27-CONUS , NAD83, or WGS84. NAD83 and WGS84 are equivalent for a practical purposes. See this link for more details. Which lat/lon format should I use? Your choices are... hdd.ddddd - Decimal Degreeshddd mm.mmm - Decimal Minutes hddd mm ss.s - Degrees, Minutes, and Seconds Outside influences usually decide this for you. For example what format does the guide book, website, or program use? Does your team or group of friends use a particular format. My own preference is to use decimal minutes (hddd mm.mmm), when nothing is pushing me to use something else. What is the User UTM Grid setting used for? Some other countries in out of the way parts of the world have used coordinate systems that are UTM like, but not lined up with the standard UTM zone scheme. By determining values for Longitude Origin, Scale, False Easting, and False Northing, the GPS can usually display these coordinate systems. Do I use UTM/UPS or User UTM Grid? Use UTM/UPS. How do I set my GPS receiver to use UTM? You will want to go into the setup menus for your GPS and look for menus like "Navigation" and "Position Format". You should find a menu that gives you choices like: MGRS UTM/UPS USER UTM GRID hdd.ddddd hddd mm.mmm hddd mm ss.s You want to select UTM/UPS. I'm very bad at directions and maps, will a GPS help me? Probably not. A basic GPS will do little more that report your current position as a geographic coordinate. You'll need to relate these coordinates to your position on a map and then decide how to navigate based on that. It is however useful to recall that humans have been able to navigate successfully without maps and high-tech gadgets for thousands of years. I've been working on how to teach people to navigate without such a reliance on gadgets. I'll put a link to this info once the page is up. Can you recommend a good GPS? This is a bit like asking me what kind of car you should buy. Which GPS is right for you will depend on - what you want to do with it, how skilled you are at understanding new gadgets, and what your personal preferences may be. That said, I do have some thoughts about what folks should consider when buying a GPS. First a small disclaimer...I don't sell GPS units or represent any GPS manufacturer. These opinions are my own. The uses I have for a GPS may be different than yours, so my recommendations may not apply. The product development cycle is short, new models are released frequently. As I do not spend much time looking at or lusting over each and every new model, my information may be out of date. The most common uses I have for a GPS are: Getting a coordinate for my present location so that I can relate it to a map, save it for future reference, or report it to someone else by radio. Navigating to a known coordinate that I have entered into the GPS. Note that the GPS will only give you the straight line path as a distance and direction. On land, this is seldom the right path to follow. Recording a series of coordinates to use in adding a road or trail to an existing map. Hooked to a laptop in the car to create a moving map. I like to take out of the way dirt roads when I'm traveling. A bit of adventure for me and a good place to let the dogs out for a break. Using the moving map feature of programs like DeLorme's TOPO USA or National Geographic's TOPO! (Yes TOPO works on my Mac iBook!) you can plan ahead on where to turn off and have some idea where the dirt road will take you. Being able to power both the GPS and the laptop from the car is a good thing when you're operating like this. Lucky for me almost all of the GPS receivers can preform these functions. I tend to be a minimalist when it comes to both price and extra features. Here are some of the things I'm not willing to pay much extra for: - Built in maps Who wants to look at their topo map through a 1.5" X 3" window! Paper maps give you good detail, and they let you see the relationship of the various terrain features that are around you. On the GPS you have to zoom out to see the surrounding terrain, and when you zoom out you loose the detail. Try it out, cut out a small window in a piece of paper and place it over your topo map, does it still seem as useful? Plus the paper map is a necessary backup that doesn't require batteries. - Color displays Since I'm not interested in loading it with map data, I don't have much need for a color display. - Built in compasses, altimeters, radios, mp3 players, etc. I prefer to have these as separate devices. My compass is low tech, light weight and has never run low on batteries. Same is true with my altimeter. My GPS is usually turned off and tucked away in my pack. I only use it continuously, when I'm recording a track, or getting very close to the destination coordinates that I'm seeking. Here are a few features that I think are useful. Light weight, good battery life, uses 2 AA batteries WAAS (Wide Area Augmentation System) External Antenna "Map" display that shows current track and waypoints Dual position format display i.e. Lat/Lon and UTM Data port, so you can transfer waypoints and tracks and use the moving map feature on your laptop topo program. When I teach GPS classes, I usually group the students by GPS brand, so that they can help each other with the setup and operation details. The Garmin and Magellan groups are usually quickly on their way to the field problems while the Lowrance group is usually scratching their heads and looking at the manual. It seems the human interface Lowrance uses is just not as well thought out as the others. My observations do not necessarily reflect their latest models, they might have made significant improvements, as there has certainly been plenty of room to improve! Some of the GPS units I own and why... Garmin eTrexI own a dozen of these that I use teaching GPS classes. They're just $89 from Amazon, and have all the basic features. If you were going to own just one gps, I'd move up the eTrex product line a bit to get one that does WAAS. Garmin 12XLRugged and reliable. The XL flavor has an external antenna, which is essential for getting sufficient satellite signal in the deep wet redwood forests around here. This is a tough feature to find these days. Magellan Map330Fantastic user interface. Little things like displaying the datum along with the coordinates, and including the E and N to indicate easting and northing for UTM coordinates. Garmin iQue 3600Here I've broken all of my rules. It's pricey, and has maps and a big color display. My reason for buying this one is that it combines a Palm Pilot with a GPS, and is thus the first "all in one piece" GPS that I can write programs for. In my other life, I'm a software developer. So I tried out the driving directions feature and was surprised to find it's actually useful. The voice guidance for turns is essential. Get it all set up before you leave. Don't even think of using the user interface while you're driving. But a skilled copilot can even locate a Starbucks on the route ahead using the built-in yellow pages info. The copilot was me, the user interface was more complicated than my wife was willing to attempt. MapTools and our products Free downloadable tools When I print one of your pdf map tools, it is the wrong size or will not print. What can I do? Most of the "wrong size" problems have been related to page size and Adobe Acrobat's options that scale things to fit. Make sure the options "Shrink Oversize Pages to Paper Size" and "Enlarge Small Pages to Paper Size" are not enabled. Can you provide a free tool like...? Most of my friends think I'm crazy for posting free copies on the of the things I'm trying to sell. The short answer is that I'm not currently planning to expand the number of free downloadable tools that I make available. But, if you have a compelling reason for a particular tool to be downloadable, I'm willing to listen. It's a balancing act. One hand I want lots of people to be able to learn to use map coordinates, so I provide lots of instructions and free versions of the tools for the most common map scales. No doubt I loose a few sales to folks whose needs are met by the free tools. But, I believe I gain more sales as people discover map coordinates, and find they want the quality and variety of tools available from the online store. MapTools has evolved into a business with a significant investment in time, equipment, and inventory. It could have gone the other way, and been just a passion related to my search and rescue activities. In the end, I think I can provide the best quality tool to the most people using the business approach rather than the hobby approach. Web tutorials and exercises I put the coordinates for your sample problems into my topo map program, and they are out in the middle of the ocean! What am I doing wrong? The maps and coordinates in the tutorials are fictional and are not intended to represent real locations. This should have no impact on their usefulness as an educational tool. A grid tool or ruler placed on the map will produce the expected answers. On the other hand, putting the coordinates into a computer based mapping system is not likely to yield useful information. I'm getting the wrong answers on the UTM sample problem, any ideas what I might be doing wrong? Don't align your grid tool with the edges of the map, called neat lines, they are NOT UTM grid lines in most cases. Line your grid up with the UTM Grid lines. When you are near the edge of the map, a portion of the grid may be off the map and you may need to use the value of a grid line that i s not visible as the base of your coordinate measurement. Using our products Is the information in the UTM booklet the same as the information on the web page? For the most part the information is the same. In a many places the booklet goes into more detail. The major difference is in packaging. The booklet provides a nice compact portable high resolution version of the information. The UTM grid I have does't fit the grid on my map. What's wrong? Usually this means the grid you are trying to align the tool with is not a UTM grid. The most frequent confusion come from the public land survey section lines. On a USGS 1:24,000 scale map they are dashed red lines, with red section numbers in the center, they roughly define a 1 mile grid. See this FAQ answer for some hints on locating the UTM grid marks. Can I set the declination on a Brunton 54LU compass? No, It will only give readings relative to magnetic north. See this FAQ answer for a reason why this may be the right thing to do anyway. The lat/lon ruler does not fit the lat/lon grid on my map. Why not? If it is way too long east-to-west... Remember the lines of longitude converge at the poles. That is to say the further north or south you go from the equator, the closer together they get. You need to use the ruler on a diagonal to compensate for this. Instructions are here. If it is way too long north to south... Not all maps use the same size lat/lon grid. You may be using a 7.5 minute ruler with a five minute grid spacing. In this case, only use the portion of the ruler from 0 to 5 minutes. If it is way too short north to south... Not all maps use the same size lat/lon grid. You may be using a 7.5 minute ruler with a 15 minute grid spacing. In this case, you will want to draw in additional grid lines to end up with a 7.5 minute grid spacing.. If it is just a bit too long north to south... It turns out that the lines of latitude also get just a bit closer together as you move north or south from the equator. This is because the earth is an ellipsoid, not a sphere. MapTools lat/lon rulers are sized for an exact fit at 40 degrees north and south of the equator. For most of our users this will make the ruler about a millimeter too long. Most folks never even notice, and the results they get are well with in their accuracy requirements. To compensate for this you can use the ruler on a slight diagonal, much like you do when measuring longitude. If it is just a bit too short north to south... You may be further north or south than 40 degrees. But most likely the scale on your map is not quite correct. I've seen an issue with my oldest DeLorme Atlas and Gazetteer for California. Puzzled, I did some more research and found that the old CA atlas was not really exactly a 1:150,000 scale. I ran out and bought a newer atlas, and it was right on. I ran all of the calculations for the length of my ruler, and double checked them against a USGS map as well. The ruler was correct. My guess is that when the DeLorme Atlas series was first published, nobody was using the lat/lon lines since GPS receivers were not common back then. And a small error in a distance measurement would likely go unnoticed. On the other hand maybe the paper has stretched a bit, with years of use and less than ideal storage conditions. I've not been able to confirm the problem with DeLorme. Only one or two customers have noticed this problem since I started selling the rulers back in 1999. How durable are your tools? Will the ink wear off? The UTM tools are printed on 30 mil clear stock, and then a protective coating is applied. We use either a film overlay or a UV cured clear coat. Repeated abrasion of the protective coating will eventually wear it off and then the markings will soon wear off as well. For day to day field use they seem to be quite durable. I tested this out by carrying one of the Pocket Corners around in my pocket with my keys and coins for a month. The tool developed a frosted look from the many small scratches it picked up, but the markings were all still there, and the tool was still quite usable. The 30 mil plastic stock is similar to a credit card in both thickness and flexibility. You can bend the tools in half, without breaking them. When you unbend the tool, you'll have an ugly white crease mark, but the tool will most likely still be usable. Do you have a tool for this scale? The cartographer or map maker selects a map scale based on the size of the area they are mapping and the size of the sheet the resulting map gets printed on. It's common to find map scales ranging from 1:1 all the way to 1:10,000,000. The tools we sell, get printed in large batches, and we only do that for the popular map scales. I am slowly expanding the number of scales that I stock. If you have a common scale for maps in your area, that you think I should stock, let me know, and I'll add it to the list under consideration. In the past several decades, mapping projects done for an entire country are usually done by a government agency. Typically these agencies will select one or more scales to use for their map series. Using a consistent set of scales allows the maps sheets to be used adjacent to one another. Cartographers making a single map of a specific area, like a park, often choose a scale to fit the area onto a reasonable or standard sized sheet of paper. The National Geographic Trails Illustrated map series is a good example. They use more than 60 different map scales in their series of several hundred maps. As maps and map production move into the digital world it becomes very easy to adjust the output scale to satisfy your particular needs. Whenever it is reasonable to do so, you should stick with the more popular scales for printed maps. This will allow users of the map to use the map along with other printed maps of the area, as well as allowing them to use the common coordinate and distance measuring tools. Purchasing our products Will you accept government credit cards or purchase orders? Yes. We do a great deal of business with federal, state and local government agencies and are happy to accommodate your particular agency's purchasing requirements. Our online shopping cart will accept orders using government credit cards or purchase order numbers. Federal government end users in California can request an exemption from sales tax during the checkout process. We don't charge sales tax for orders that ship outside of California. If you need a formal written quote, you can either call or email us, or you can place an online order with the PO number of "Quote". We'll review the order and email you a quote. Do you sell maps? Not directly. We have partnered with the folks at MyTopo to provide maps. Here are some hints and tips for ordering a map from MyTopo. I've also been downloading maps from the folks at CalTopo.com. Their maps are free and can be downloaded as a pdf file. Can I shop in person at your retail store? We don't have a retail store. We do have a warehouse and production facility in San Carlos, CA. If you are local, you can come and get tools directly from us. Please make prior arrangements, so that we can be sure to be here. We do things like taking off for a hike or to go work out at the gym in the middle of the day, so there is not someone at the warehouse during predictable hours. Do you have a dealer in ...? We have a handful of retailers that carry our products in their brick-and-mortar and/or online stores. See our Dealer List for a current listing. Most of these stores stock only a few of out most popular products. So it's a good idea to call ahead to check if they have what you are looking for. I don't trust the Internet with my credit card info. Can I place an order by phone? Yes. You can give us a call at . John is currently the only person that answers the phone. My hours are generally M-F, 9am to 5pm pacific time. But I am frequently away from the phone so you will likely need to leave a message. But let me try and talk you out of calling to place an order. When you call, and I actually answer, I'll likely be on my cell phone. I might be out on the production floor, in a meeting, running an errand, at the gym, or on a hike. I'll find a scrap of paper and take down your order information, and stuff it into my pocket. Really, we do not have agents standing by. This is low tech, and only somewhat secure and reliable. But it's how lots of tiny scrappy businesses like ours run. You should at least place your order on the internet. You can still choose the payment option for calling your credit card in by phone. If you do put your credit card information in on out web based shopping cart. It first gets encrypted right in the web browser on your computer. Then it gets sent over an encrypted link to our credit card processing company, where they can afford the top-gun security guys to keep it safe. Here at MapTools, we never have your credit card info, we just get a token that allows only us to charge the amount of the order, or to issue a refund up to the amount of your order. So it's up to you to decide. You can use what I just described with our secure shopping cart, or your credit card info can live on a slip of paper in my pocket, or on my desk, until it gets sent to our credit card processor using my computer instead of yours. I do promise to either shred or eat the slip of paper once I'm finished getting it into the computer. Still worried? You can mail us an order, using a money order for payment. Best to pay for the money order using cash. How can I purchase your products? Our complete product line is available on our web site, MapTools.com/products. You can also get a list of our products sorted by map scale at, MapTools.com/products/byscale. We also sell many of our products through Amazon.com. We have a handful of retailers that carry our products in their brick-and-mortar and/or online stores. See our Dealer List for a current listing. Most of these stores stock only a few of out most popular products. So it's a good idea to call ahead to check if they have what you are looking for. About your order Where is my order? I need my order by a specific date. Will it get here in time? We'll try hard to make sure it does. But you need to let us know that you need it by a specific date. At the very least add a note to your order when you checkout. If time is short, it's best to call or email so that we can figure out the best delivery option without having to spend way too much money on shipping. My order should have arrived by now... Send us an email at , remember to include your order number. Several things may have occurred: Your order was lost by the Post Office. We had a problem processing your order and you didn't get or didn't respond to our email inquiry. You gave us an address that the Post Office could not deliver to. In which case your order is likely on its way back to us. You are too optimistic on the time it should take to arrive, and just need to wait a bit. Despite their motto about snow, sleet and hail, bad weather and other natural disasters do delay the delivery of the mail. Sometimes it takes a bit longer than we both think it should. And yes on rare occasions our computers burp and loose an order completely. Once we get your email, will sort out what we think should have happened. You can save another cycle of email back and forth by confirming your shipping address in your first email. When we're sure we have the right address, and it really should have arrived by now, we'll reship your order. We do ask that if you happen to receive two shipments, that you return the second one to us. This is easy, just cross out your address, and write "Return to Sender" on the shipment, and give it back to the Post Office folks. Did you ship my order? I didn't get a confirmation email. Our computer system will send you and email to confirm that we received your order, and again when we ship your order. Both emails will be addressed from . If you don't get these emails, it is most likely because a spam filter somewhere between our computer and yours decided the email was spam and filtered it. It may be sitting in your Spam or Junk mail folders. Since we are a tiny business most spam filters don't "learn" that our customers really do want our emails. Occasionally our customers enter their email incorrectly and it will fail to be delivered. You can always email us at to inquire about your order. Please include your order number. We'll do our best to get a quick answer to you regarding the status of your order. How are orders shipped? Most of our orders are small, flat, and weigh under 13 ounces. This makes USPS First Class Mail the lowest cost reliable shipping option. Orders are shipped from . Most orders ship in a flat brown 6"x9" envelope and will be delivered along with the rest of your first class mail. These first class mail envelopes are not trackable. Once they have been mailed we can not get any information about them unless they get returned to us by the Post Office because they were undeliverable. Our web site offers Priority Mail and Express Mail as faster and more costly shipping options, both of which are trackable. We have to have Express Mail shipments to the Post Office by 3pm pacific time, if we want their delivery commitments for that day. Orders that are placed through Amazon.com and shipped by MapTools are shipped the same way the rest of our orders are, with one exception. Amazon pushes us really hard to provide tracking information for shipments. So we charge a bit more for these orders and ship them as a First Class Package, which unlike the envelopes is trackable. Overall this has been working really well, but there are a few postal clerks out there that are not up to speed on the First Class Package rules, and return them to us with the explanation that First Class Letters and Flats are not eligible for tracking. We can also ship using UPS and FedEx. But our shopping cart will not offer those options yet. So you need to call or email if you need that sort of shipping. We're working on a better shopping cart. But progress is slow. When are orders shipped? We ship most of our orders on the same business day we receive them. We ship Monday through Friday, with holidays on pretty much the same days the US Post Office has holidays scheduled. The postal carrier picks our mail up sometime between 10 am and 3pm pacific time. When orders are ready to ship after our postal carrier has come by, we take often take the envelopes to the corner mailbox just before 5pm when its contents get picked up. Packages usually have to wait to the next day.

### Government Purchasing — MapTools Government Purchasing Over the years, we have sold products to many different government entities.
https://maptools.com/government

MapTools Government Purchasing Over the years, we have sold products to many different government entities. We will be happy to work with your purchasing folks to meet their needs. The simplest way for many federal entities to purchase our tool, is directly from our website, using your government purchasing card. Federal government entities are exempt from state sales tax and there is an option to indicate your tax-exempt status at checkout. You can obtain a pricing quote from us using our web shopping cart. Just select "Quote Only" as the payment method at checkout. Our CAGE code is: 49DG4 Our Unique Entity ID is: HDFJKEN1A488 We gladly accept purchase orders for federal, state, and local entities, as well as public schools, colleges, and universities. No credit applications or other paperwork are necessary. Our pricing is based on the quantity of tools purchased, not who you are or what your mission is. We are trying to make more and more of our discounts available directly from our website. Most of our products are covered under the Berry Act as "hand measuring tools" and they are compliant. Our Berry Act Compliance Certification is here: BerryActCertification.pdf Our products are not "Covered Telecommunications Equipment or Services." Our certification to that effect (Form 889) is here: 889_Representation_Form.pdf If your needs are not met by what you find on the site, please contact us directly for a quote.

### Grid Zone Details — More details about UTM Grid Zones The world's 60 UTM zones The UTM coordinate system divides the earth into 60 zones each 6 degrees of longitude wide.
https://maptools.com/tutorials/grid_zone_details

More details about UTM Grid Zones The world's 60 UTM zones The UTM coordinate system divides the earth into 60 zones each 6 degrees of longitude wide. These zones define the reference point for UTM grid coordinates within the zone. UTM zones extend from a latitude of 80° S to 84° N. In the polar regions the Universal Polar Stereographic (UPS) grid system is used. Note that there are a few exceptions to zone width in Northern Europe to keep small countries in a single zone. UTM zones are numbered 1 through 60, starting at the international date line, longitude 180°, and proceeding east. Zone 1 extends from 180° W to 174° W and is centered on 177° W. Each zone is divided into horizontal bands spanning 8 degrees of latitude. These bands are lettered, south to north, beginning at 80° S with the letter C and ending with the letter X at 84° N. The letters I and O are skipped to avoid confusion with the numbers one and zero. The band lettered X spans 12° of latitude. Eastings and Northings within a zone A single grid zone measures about 20,000km tall and only about 700km wide. So the above diagram has been compressed in the vertical axis by about 15X. The eastern and western zone boundaries are truly much straighter. A square grid is superimposed on each zone. It's aligned so that vertical grid lines are parallel to the center of the zone, called the central meridian. UTM grid coordinates are expressed as a distance in meters to the east, referred to as the "easting", and a distance in meters to the north, referred to as the "northing". Eastings UTM easting coordinates are referenced to the center line of the zone known as the central meridian. The central meridian is assigned an easting value of 500,000 meters East. Since this 500,000m value is arbitrarily assigned, eastings are sometimes referred to as "false eastings" An easting of zero will never occur, since a 6° wide zone is never more than 674,000 meters wide. Minimum and maximum easting values are: 160,000 mE and 834,000 mE at the equator 465,000 mE and 515,000 mE at 84° N (Exceptions to this will be found in the unusual zones in northern Europe.) Northings UTM northing coordinates are measured relative to the equator. For locations north of the equator, the equator is assigned the northing value of 0 meters North. To avoid negative numbers, locations south of the equator are made with the equator assigned a value of 10,000,000 meters North. Some UTM northing values are valid both north and south of the equator. In order to avoid confusion the full coordinate needs to specify if the location is north or south of the equator. Usually this is done by including the letter for the latitude band. If this is your first exposure to the UTM coordinate system you may find the layout of zones to be confusing. In most land navigation situations the area of interest is much smaller than a zone. The notion of a zone falls away, and we are left with a simple rectangular coordinate system to use with our large scale maps.

### Interactive UTM/MGRS/USNG Tutorial
https://maptools.com/tutorials/utm-viewer/

### International Orders — I'm sorry to say, but MapTools no longer ships order internationally, except for rare circumstances.
https://maptools.com/international-orders

I'm sorry to say, but MapTools no longer ships order internationally, except for rare circumstances. Read on to understand why. For may years MapTools shipped small orders all over the world using First Class Mail International (FCMI). A typical shipment would be $10-15 of merchandise, with the postage being about the same amount for a flat letter. Duties and taxes were the responsibility of the receiver. Successful deliveries only occurred about 50% of the time. We would frequently need to ship an order 2 or three times before it would make it to our customer. Generally we lost a small, but acceptable amount of money on every international order. Around 2021 our postal service tightened up enforcement of their rule that "flats sent via FCMI must contain only documents. We tried putting the orders in parcels, which doubled the cost and reduced delivery reliability. We tried Priority Mail International at four times the cost. Delivery was a little better, but lost shipments were costing us too much." We have had good success with FedEx and UPS, but we often get a nasty surprise of a second bill from them for the taxes and duties. So the policy has evolved to requiring the customer to provide a UPS or FedEx account to bill all of the shipping, taxes, duties, etc. to. The cost of FedEx or UPS shipping is often more than US$100. So this really doesn't work for small orders. We also looked into having Amazon do our international fulfillment. But they require we have tax accounts in every country they ship to, and that we provide product listings and support in the local language. MapTools is small, only two of at the moment, so this is too big a hurdle for us. I feel really bad that we don't have a better way to get our products to international customers. And I'll keep looking for a solution. John Carnes, Owner MapTools Commercial Goods in Flats: USPS regulations specify that flats sent via FCMI must contain only documents. Including merchandise or commercial goods in flats is not permitted under FCMI guidelines. First Class Flat Envelope $12 First Class Package $25 Priority Mail Flat Rate Env $48

### KUTM Quick Guide — A Quick Guide to Using kUTM Coordinates Standing at the center of the marker shown on the map below, a GPS unit set to display position in UTM/UPS format, would report a location of: Let's look at where the various parts of the UTM position come from on the map.
https://maptools.com/tutorials/kutm/quick_guide

A Quick Guide to Using kUTM Coordinates Standing at the center of the marker shown on the map below, a GPS unit set to display position in UTM/UPS format, would report a location of: Let's look at where the various parts of the UTM position come from on the map. The map has grid lines spaced every kilometer or 1000 meters. The grid is labeled with UTM coordinate values. The vertical grid lines determine East-West position and the horizontal grid lines determine North-South position. Look along the bottom edge of the map at the labels for the vertical grid lines. The label, , reads "seven hundred and six thousand meters East." The label, , is an abbreviation for, The two grid lines are 1000 meters apart. The horizontal grid lines are labeled in a similar manner. The 10S is the Grid Zone Designation you are in. The Grid Zone is necessary to make the coordinates unique over the entire globe. The top set of numbers, 706832, represent a measurement of East-West position, within the Grid Zone, in meters. It's called an Easting. Using a map with a 1000m grid, the first digits are come from the label for the grid line to the west of the position. The last 3 digits are the distance in meters measured from the western grid line. The bottom set of numbers, 4344683, represent a measurement of North-South position, within the Grid Zone, in meters. It's called a Northing. Using a map with a 1000m grid, the first digits are come from the label for the grid line to the south of the position. The last 3 digits are the distance in meters measured from the southern grid line. Using various tools to plot and measure UTM positions on a map Click on the tab for the tool style you want to know more about. Grid Style Tool Slot Style Tool Corner Style Tool Mini Corner Style Tool Using a grid style tool to plot/measure a UTM position with 100m precision Using a slot style tool to plot/measure a UTM position with 10m precision Using a corner ruler roamer style tool to plot/measure a UTM position with 10m precision Using a mini corner style tool to plot/measure a UTM position with 10m precision Leading zeros on the Easting and Northing It's very common for a GPS receiver to display a leading zero on the Easting measurement, as a place holder for the millions meter digit. In our example the GPS shows an easting of 0706832. We typically drop the leading zero when we write the number. If you made a purchase for $706.83, you probably wouldn't write that as $0706.32. But if you were filling out a form with a box for each digit, you would want to get the digits in the right place. Your GPS fills the "empty boxes" on the left with zeros. You should too, when you are entering a coordinate into your GPS. For improved clarity, write the measurement units with the Easting and Northing In the world of map coordinates, there are a lot of different coordinate formats. If you just run a bunch of digits together with no spacing or units, you run the risk of having someone else misunderstand what coordinate format you are using. In the case of kUTM, I suggest writing "km E" for "kilometers East" after the Easting, and "km N" for "kilometers North" after the Northing. When communicating a coordinate by voice, say the words "kilometers East" after the Easting and "kilometers North" after the Northing. There are several documented cases where a string of digits was passed, usually by voice, to someone else who misinterpreted the coordinate format. In one case this led to the rescue helicopter being sent 30 miles away from the actual incident. Learn more about... Map Datums and why they are so important Locating MGRS grid information on USGS topographic maps Grid Zone Details Metric Distance Measurements UTM Practice Exercise

### Large Training Aids — MapTools Large Classroom Training Aids I have spent a lot of years teaching land navigation in both classroom and field situations.
https://maptools.com/large-training-aids

MapTools Large Classroom Training Aids I have spent a lot of years teaching land navigation in both classroom and field situations. One of the things I found useful was to have large versions of some of the small tools that the students use. I could hold them up and demo what I wanted the students to be doing with their tools. I was able to buy a “big demo compass” from Brunton many years back and I made larger versions of a few MapTools products to use. Brunton doesn’t sell their “big compass” anymore and gluing bits of printed overhead transparency material to plexiglass sheets was too tedious do make more than the few tools I needed. At one point I had some GTA and SuperGTA tools made in a large format at a local screen printing shop. I was cutting them out using a ShopBot CNC machine at a local maker space. They were not big sellers and eventually the maker space closed, ending my ability to make them. So now in 2022, MapTools has the equipment to print on clear plastic stock one sheet at a time, and to laser cut the printed results as well. So now I can once again offer our large classroom training aid products. Links to the current products… UTM Grid Style Classroom Training Aid UTM Slot Style Classroom Training Aid Corner Ruler Style Classroom Training Aid Mini Corner Style Classroom Training Aid Map Ruler Style Classroom Training Aid Compass Classroom Training Aid In the planning and design stage are: GTA and SuperGTA military protractors Here are some photos and explanation of the tools as they would be used for training. Making a “map” to use with the UTMGrid and UTMSlot tools: Both of these tools have small holes at the corners of the 1 kilometer grid. Step 1 - Mark the corners of the first grid. If the classroom has a white board, I’ll likely be doing this on the whiteboard with a whiteboard marker. Otherwise I’ll be using a big sheet of white paper. I usually tear off a piece that’s about 3 ft. by 4 ft. in size. Step 2 - Move the tool over 1km and mark the corners of the next grid. Repeat this until you have a map the size you want to use. Step 3 - Draw in the grid lines, and add the UTM coordinate labels. Step 4 - Add a few features, and the map is ready The UTMGrid and UTMSlot training aids are both the same scale. The plan is to make the UTM Mini Corner, the UTM Corner Ruler, and the kilometer edge of the Lat Lon ruler all the same scale. That way you can demonstrate how the different tools work, using the same practice map. The tools have a scale of 1:6,369. The GTA and SuperGTA tools are both larger tools. Since our print size is limited to a width of 12 inches, I’ll have to make them a different scale. If you want something more "map like" than a white background with some grid lines and labels, you can make a topo map at 1:6,369. Here is a link to a training map I made using CalTopo.com You can get it printed on you own, or you can have us get it printed and laminated for you. I use PosterBrain.com Their current pricing (April 2022) is $54 for printing, $12 for lamination, $8 for Priority Mail shipping. We charge more than they do, but then we are doing the work. It's easy and you should really do it yourself. Some tips for making your own CalTopo Training map - You’ll need a paid subscription to generate large PDFs - I created a 36" x 48" map. - Use a 1:6,369 scale. (Chose Custom Scale and enter 6369.) - Use 1km UTM Grid lines - If you are using a USGS scanned base map with printed UTM Grid lines, you’ll likely want to use the NAD27 datum or you will have 2 sets of grid lines, which makes for a confusing demo. - The coordinate labels will be in a tiny type size. Plan to add them by hand if you want the class to be able to see them. - PosterBrain has a max file size of 100 MB. I exported the pdf file as a 150 dpi TIFF file to get it under 100 MB. Laminate the map, so you can reuse it. Measuring coordinates of points on the map. Grid tool Use the SW corner of the grid to determine the coordinates of the grid square. The green triangle is in the 1km grid square at 246,000km E and 4,279,000m N. Place the tool in the grid square and use it to measure within the grid, we see that the green triangle is in the 100m square that is 200m further east and 500m further north. So the resulting UTM coordinate of the green triangle is 246,200m E 4,279,500m N. If we were demonstrating MGRS or USNG coordinates, we would take the first two digits of the easting an northing using the large type digits at the SW corner of the grid square. (or the 10,000 and 1,000 meter digits, if you do not have the large type hints.) So the grid square is 46 79. We would get the third digit (the 100m value) using the tool. The green triangle is at 462 795 in 100m abreivated MGRS or USNG coordinates. The red X is at 248,600m E 4,280,600m N UTM or 486 806 MGRS or USNG 100m. The red X is right on the line between the 500m N and 600m N squares on the tool. You have to choose, I went with the larger northing. Slot Tool Using a slot style tool, we can measure the coordinates of the red X with a 10-meter precision. Again get the grid coordinates using the SW corner of the grid. The 1km grid can be described with the coordinates 248,000m E 4,280,000m N UTM or 48 80 MGRS or USNG 1000m Place the bottom scale of the slot tool on the southern edge of the grid square. Check that the top of the 1km scale of the tool is on the northern grid line. (if it's not, your toom doesn't match you map scale.) Slide the tool east or west until the red X in centered in the slot. Measure the easting distance within the grid where the western grid line cross the scale on the bottom of the tool. In this case three tics past the 6, or 630m further east. Measure the northing distance within the grid at the red X. In this example, right at the 6, or 600m further north. The red X is at 248,630m E 4,280,600m N UTM or 4863 8060 MGRS or USNG 10m. Partial Grids Plotting a coordinate onto the map Grid Tool Slot Tool Using the protractor to measure a bearing between two points Using the protractor to plot a bearing from a know point Plotting the back bearing Using a compass to measure a bearing Using a compass to plot a bearing The compass set up for grid north readings ready to follow a bearing

### Lat/Lon Coordinate Formats — Symbols for degrees, minutes and seconds: ° Degrees ' Minutes " Seconds The three common formats: DDD° MM' SS.S" Degrees, Minutes and Seconds DDD° MM.MMM' Degrees and Decimal Minutes DDD.DDDDD° Decimal Degrees Degrees, Minutes and Seconds DDD° MM' SS.S" 32° 18' 23.1" N 122° 36' 52.5" W This is the most common format used to mark maps.
https://maptools.com/tutorials/lat_lon/formats

Symbols for degrees, minutes and seconds: ° Degrees ' Minutes " Seconds The three common formats: DDD° MM' SS.S" Degrees, Minutes and Seconds DDD° MM.MMM' Degrees and Decimal Minutes DDD.DDDDD° Decimal Degrees Degrees, Minutes and Seconds DDD° MM' SS.S" 32° 18' 23.1" N 122° 36' 52.5" W This is the most common format used to mark maps. It's also the most cumbersome to work with. It's a lot like telling time&#133; There are sixty seconds in a minute (60" = 1') and There are sixty minutes in a degree (60' = 1°). Keeping in mind a few easy conversions between seconds and decimal minutes will help when working with maps that use degrees, minutes and seconds. 15 seconds is one quarter of a minute or 0.25 minutes 30 seconds is one half of a minute or 0.5 minutes 45 seconds is three quarters of a minute or 0.75 minutes Degrees and Decimal Minutes DDD° MM.MMM' 32° 18.385' N 122° 36.875' W This is the format most commonly used when working with electronic navigation equipment. Decimal Degrees DDD.DDDDD° 32.30642° N 122.61458° W or +32.30642, -122.61458 This is the format you'll find most computer based mapping systems displaying. The coordinates are stored internally in a floating point data type, and no additional work is required to print them as a floating point number. Often the N-S and E-W designators are omitted. Positive values of latitude are north of the equator, negative values to the south. Watch the sign on the longitude, most programs use negative values for west longitude, but a few are opposite. This saves a lazy western hemisphere programmer from having to type in a minus sign before most of their longitude values. Which format should you use? First off, if you are working with other people who have agreed upon a format to use, then you should probably use that format. Next, you will want to look at the maps, lists of coordinates, and any software you may be using. If you can find a consistent format among them, your work will be easier. You can set your GPS to display any one of these three formats. Locations can be entered into the GPS with the selected format, and then by switching the display format setting, viewed in a different format. I frequently choose to use the Degrees and Decimal Minutes format, even though the USGS maps I'm using are marked in Degrees, Minutes and Seconds. The markings on the map are all at either 0, 15, 30, or 45 seconds. By remembering the "quarter minute conversions" of 0.00, 0.25, 0.50, and 0.75, I can quickly do the conversions in my head. | Previous | Index | Next |

### Lat/Lon Definitions — Latitude Lines of latitude measure north-south position between the poles.
https://maptools.com/tutorials/lat_lon/definitions

Latitude Lines of latitude measure north-south position between the poles. The equator is defined as 0 degrees, the North Pole is 90 degrees north, and the South Pole is 90 degrees south. Lines of latitude are all parallel to each other, thus they are often referred to as parallels. The memory rhyme I use to help remember that lines of latitude denote north-south distance is: "Tropical latitudes improve my attitude" One degree of latitude is 60 nautical miles, 69 statute miles or 111 km. One minute of latitude is 1 nautical mile, 1.15 statute miles, or 1.85 km. Longitude Lines of longitude, or meridians, run between the North and South Poles. They measure east-west position. The prime meridian is assigned the value of 0 degrees, and runs through Greenwich, England. Meridians to the west of the prime meridian are measured in degrees west and likewise those to the east of the prime meridian are measured to by their number of degrees east. The memory rhyme I use to help remember that lines of longitude denote east-west distance is: "Lines of LONGitude are all just as LONG as one another." With this saying in my mind, I picture all the longitudinal meridians meeting at the poles, each meridian the same length as the next. | Index | Next |

### Lat/Lon Exercise Answers — Answers to the Lat/Lon Exercise Measuring coordinates for points on the map: A &#150; 37° 35' N 122° 05' W B &#150; 37° 32.5' N 122° 06.5' W or 37° 32' 30" N 122° 06' 30" W C &#150; 37° 36.8' N 122° 02.3' W or 37° 36' 45" N 122° 02' 15" W Plotting coordinates onto the map: 37° 35' N 122° 05.8' W is the camp site 37° 31' 30" N 122° 02' 10" W is the mine 37° 33.6' N 122° 03.7' W is the ranger station
https://maptools.com/tutorials/lat_lon/answers

Answers to the Lat/Lon Exercise Measuring coordinates for points on the map: A &#150; 37° 35' N 122° 05' W B &#150; 37° 32.5' N 122° 06.5' W or 37° 32' 30" N 122° 06' 30" W C &#150; 37° 36.8' N 122° 02.3' W or 37° 36' 45" N 122° 02' 15" W Plotting coordinates onto the map: 37° 35' N 122° 05.8' W is the camp site 37° 31' 30" N 122° 02' 10" W is the mine 37° 33.6' N 122° 03.7' W is the ranger station

### Lat/Lon Practice Exercise — An Exercise to Test Your Knowledge This exercise will test your ability to plot Lat/Lon coordinates onto a map and to determine the coordinates of features on the map.
https://maptools.com/tutorials/lat_lon/exercise

An Exercise to Test Your Knowledge This exercise will test your ability to plot Lat/Lon coordinates onto a map and to determine the coordinates of features on the map. The pdf file linked below contains a very simple 1:100,000 scale map, the instructions for the exercise, and a 1:100,000 scale Lat/Lon ruler. Cut the ruler out, and use it for the exercise. llexercise.pdf (195k) Use this link if you need to download a copy of the Adobe Acrobat Reader for your computer. The Answers... Click here for the answers to the exercise. | Previous | Index|

### Lat/Lon Quick Guide — A Quick Guide to Using Lat/Lon Coordinates Plotting and Measuring Latitude Latitude represents a north-south position on the earth.
https://maptools.com/tutorials/lat_lon/quick_guide

A Quick Guide to Using Lat/Lon Coordinates Plotting and Measuring Latitude Latitude represents a north-south position on the earth. I use the rhyme &#147;tropical latitudes improve my attitude&#148; as a memory crutch. Latitude increases as you move towards the poles. Because the lines of latitude are parallel and evenly spaced, a degree of latitude represents a constant distance on the ground. Place the ruler so that it spans the lines of latitude that the point to be measured or plotted falls between. Orient the ruler north to south. The zero minute end of the ruler should be on the southern line of latitude. (In the northern hemisphere.) To measure the latitude of a point on the map: Read the value from the ruler at the point Add it to the latitude of the line at the zero end of the ruler. To plot the location of given coordinates: make a small tic on the map to indicate the line of latitude the coordinates fall on. Plotting and Measuring Longitude Longitude represents an east-west position on the earth. Longitude increases as you move away from the prime meridian, or 0°, in Greenwich, England. Because the lines of longitude converge at the poles, a degree of longitude represents a varying distance on the ground, depending on the latitude. Place the ruler so that it spans the lines of longitude that the point to be measured or plotted falls between. The ruler will need to be on a diagonal to fit. To measure the longitude of a point on the map: Slide the ruler vertically, keeping the ends on the lines of longitude marked on the map, until the edge of the ruler touches the point to be measured. You may need to extend the lines of longitude above or below the map to properly position the ruler. To plot a longitude coordinate: Make a small tic on the map to indicate the line of longitude. The point of interest is located where the plotted lines of latitude and longitude cross. Want more details? Latitude and Longitude Defined Formats and Symbols Plotting and Measuring Lat/Lon Video Tutorial on Plotting and Measuring Lat/Lon An Exercise to Test Your Knowledge Answers to the Exercise MapTools Lat/Lon Rulers Map Datums and why they are so important

### Latitude / Longitude Coordinates — Using the Latitude Longitude Coordinate System The latitude longitude coordinate system uses angular measurements to describe a position on the surface of the earth.
https://maptools.com/tutorials/lat_lon

Using the Latitude Longitude Coordinate System The latitude longitude coordinate system uses angular measurements to describe a position on the surface of the earth. The system has been in use, with little change, since the astronomer Ptolemy used them in his first world atlas in A.D. 150. Mariners and aviators have been the primary users of latitude/longitude in the past. The system is used on a worldwide basis and many different types of maps have lat/lon markings. Recently, the availability of inexpensive Global Positioning System receivers has made position information available to many more people than ever before. With that comes the need to understand how coordinate systems work, and how to relate them to points on a map. Most GPS receivers are set to use lat/lon coordinates as their default factory setting. Thus, most new GPS users start out using lat/lon coordinates. There are other geographic coordinate systems in common use. You may find that they are well suited to your needs and easier to use than lat/lon. Refer to the page on Selecting a Geographic Coordinate System for a comparison of different systems. The following pages should provide you with the details you need to successfully work with the lat/lon coordinate system. Latitude and Longitude Defined Formats and Symbols Plotting and Measuring Lat/Lon Video Tutorial on Plotting and Measuring Lat/Lon An Exercise to Test Your Knowledge Answers to the Exercise MapTools Lat/Lon Rulers Map Datums and why they are so important

### Map Datum Tutorial — Map Datums An incorrect datum, can put you hundreds of meters from your actual position The datum you have set up in your GPS receiver must match the datum used to create the map you are using.
https://maptools.com/tutorials/map_datum

Map Datums An incorrect datum, can put you hundreds of meters from your actual position The datum you have set up in your GPS receiver must match the datum used to create the map you are using. The three common datums in use in the Continental United States are: NAD 27 CONUS - North American Datum of 1927 for the Continental United States (Common on older USGS maps) NAD 83 – North American Datum of 1983 (Used on most newer USGS maps) WGS 84 – World Geodetic System of 1984 (The default datum used by the GPS system) Most USGS topographic maps are based on an earlier datum called the North American Datum of 1927 or NAD 27. (Some GPS units subdivide this datum into several datums spread over the continent. In the Continental United States use NAD27 CONUS.) The Global Positioning System uses an earth centered datum called the World Geodetic System 1984 or WGS 84. WGS 84 was adopted as a world standard from a datum called the North American Datum of 1983 or NAD 83. There is typically only a meter or two difference between WGS 84 and NAD 83 in the Continental United States. The difference between WGS 84 and NAD 27 can be as much as 200 meters. A failure to use the correct datum can introduce hundreds of meters of position error. The datum is an important component of a coordinate. A coordinate with an unknown datum is an approximate location at best. The datum should be written with individual coordinates or included with explanatory notes when many coordinates are used. Cartographers that include a coordinate grid on their maps, must also specify the datum used. What is a datum? Map making begins with surveying. When you survey large areas, you need to take the curvature of the earth into account in your calculations. The earth is a lumpy bumpy three-dimensional thing, that can be approximated with a nice clean mathematical ellipsoid. Various regions of the world selected an ellipsoid that best approximated their portion of the earth. Prior to advent of satellites, most surveying was done on the ground or by using photos taken from an airplane. Early maps and surveys were carried out by teams of surveyors on the ground using transits and distance measuring "chains". Surveyors start with a handful of locations in "known" positions and use them to locate other features. These methods did not span continents well. Frequently they also did not cross political borders. The "known points", their positions and the ellipsoid used are the information that the map datum is based. NAD 23 CONUS datum is one of these terrestrial based datums established from a triangulation station in Meades Ranch, Kansas. As space based surveying came into use, a standardized datum based on the center of the earth and an ellipsoid that was a good fit to the entire surface of the earth was developed. WGS 84 is a datum in this category. There is a good article in Wikipedia about the various North American datums and their history. Finding the datum used by your map Every map that shows a geographic coordinate system such as UTM or Latitude and Longitude with any precision will also list the datum used on the map. You should always set your GPS unit's datum to match the datum of the map you are using. On a USGS topographic map the datum information is in the fine print at the bottom left of the map. Older USGS maps datum will almost always be NAD 27. Newer maps may be NAD 83. During the time period after 1983, but before shifting to NAD 83, there likely will be information on how many meters to shift a position to convert it from NAD 27 to NAD 83. Think of this as the error that will be introduced if you leave your GPS unit set to WGS 84. A dashed cross in the SW and NE corners of the map gives a visual indication of the difference between the two datums. Setting the datum used by your GPS Most GPS receivers designed for use with land navigation allow you to change the Map Datum in the Set Up menu. Here is a typical Set Up menu. If you have somehow set your GPS to use the Borneo Datum of 1818, it's hard to say how far off you position may be. Let's just sat that this "datum thing" is something you need to pay attention to. Using maps and charts with different datums on the same mission If you are coordinating with ships or aircraft, they will likely have their datum set to WGS 84, as most nautical and aviation charts now use WGS 84. Should you worry about the difference in datums? Typically, a pilot will not have any difficulty locating you on the ground if you can get them within several hundred meters of your location. This may not be the case for a ship in rough seas. If you are engaged in a mission that requires more precision, then your datums should match, or you should convert coordinates to the other datum. MGRS and USNG 100,000-meter Square Identifications are Different when Used with the NAD 27 Datum Both the MGRS and USNG systems default to the WGS84 datum. They differ when used with the NAD 27 Datum. This is particularly important to users within the Continental Unites States, where many topographic maps produced by the United States Geologic Survey are referenced to the NAD 27 Datum. The MGRS System shifts the second letter of the 100,000-meter square identification by ten letters (excluding I and O). The USNG system does not make this letter shift, but does require that the datum be specified. Ihe example coordinate we have been using would look like this when referenced to the NAD 27 Datum: MGRS: 10S GU 0706832 4344683 USNG: 10S GJ 0706832 4344683 (NAD 27) The letter shift also occurs in MGRS when working with other datum that use the Bessel 1841 and Clarke 1880 ellipsoids, which includes much of Africa, Japan, Korea, and Indonesia. When you are working with old maps and MGRS coordinates, be aware that occasional unusual letter adjustments have been used in the past.

### Map Scale Calculator — Map Scale Calculator Calculate map scale given equivalent map and ground distances Map Distance: Equivalent Ground Distance: When 1 millimeter on the map is equivalent to 1 kilometer on the ground, the map scale is 1:100000.
https://maptools.com/scale-calculator

Map Scale Calculator Calculate map scale given equivalent map and ground distances Map Distance: Equivalent Ground Distance: When 1 millimeter on the map is equivalent to 1 kilometer on the ground, the map scale is 1:100000. Calculate map distance given map scale and ground distance Map Scale: 1: Ground Distance: Map Distance Units: At a map scale of 1:100000, 1 kilometer on the ground is equivalent to 1 millimeter on the map. Calculate ground distance given map scale and map distance Map Scale: 1: Map Distance: Ground Distance Units: At a map scale of 1:100000, 1 millimeter on the map is equivalent to 1 kilometer on the ground. Get a custom map ruler for any map scale you need.

### Maps from MyTopo — Printed Maps from MapTools MapTools has partnered with MyTopo.com to provide you with custom printed topographic maps and aerial photography.
https://maptools.com/maps

Printed Maps from MapTools MapTools has partnered with MyTopo.com to provide you with custom printed topographic maps and aerial photography. Start Building Your Map Step 1 of 5: Find an area Step 2 of 5: Build your map Step 3 of 5: Choose Your Product Type Waterproof "Outdoor" Map -- Folded or Rolled Glossy "Poster" Map Laminated Map Step 4 of 5: Customize Your Map Step 5 of 5: Review Your Map

### Metric Measurements — Metric Distance Measurements If the metric system gives you a headache, here are a few tips to help you out.
https://maptools.com/tutorials/metric_measurements

Metric Distance Measurements If the metric system gives you a headache, here are a few tips to help you out. The Truth (to within 3 or 4 significant digits) What you can remember (You'll be about 10% too short.) 1 meter = 3.280 feet = 1.094 yards 1 meter ~= 3 feet ~= 1 yard 100 m = 109 yards 100 m ~= 100 yards ~= length of a football field 1000 m = 1 kilometer = 1 km = 0.621 miles ~= 5/8 mile 1000 m ~= 1/2 mile UTM, MGRS, and USNG coordinates give us locations that represent a square on the ground. The square could be as small as 1 meter on a side, or as big as 1,000 meters on a side. Here are some rough equivalents for some metric squares: 1 meter squareTwo doormats side by side 10 meter squareFour parking places 100 meter squareTwo football fields side by side 1,000 meter squareA city block

### MGRS Coordinates Quick Guide — A Quick Guide to Using MGRS Coordinates Standing at the center of the marker shown on the map below, a GPS unit set to display position in US National Grid format, would report a location of: Let's look at where the various parts of the MGRS position come from on the map.
https://maptools.com/tutorials/mgrs/quick_guide

A Quick Guide to Using MGRS Coordinates Standing at the center of the marker shown on the map below, a GPS unit set to display position in US National Grid format, would report a location of: Let's look at where the various parts of the MGRS position come from on the map. The map has grid lines spaced every kilometer or 1000 meters. The grid is labeled with UTM coordinate values. But the same grid is used for both MGRS and USNG positions. When using MGRS or USNG the small type numbers to the left of the larger type numbers are replaced by the 100,000m Square ID. The vertical grid lines determine East-West position and the horizontal grid lines determine North-South position. Look along the bottom edge of the map at the labels for the vertical grid lines. The label, , reads "seven hundred and six thousand meters East." The label, , is an abbreviation for, The two grid lines are 1000 meters apart. The horizontal grid lines are labeled in a similar manner. The 10S is the Grid Zone Designation you are in. The Grid Zone is necessary to make the coordinates unique over the entire globe. The GJ is the 100,000 meter Square ID. It identifies a unique 100,000m square within the Grid Zone. The top set of numbers, 06832, represent a measurement of East-West position, within the 100,000 meter square, in meters. It's called an Easting. Using a map with a 1000m grid, the first two digits are come from the large type on the label for the grid line to the west of the position. The last 3 digits are the distance in meters measured from the western grid line. The bottom set of numbers, 44683, represent a measurement of North-South position, within the 100,000 meter square, in meters. It's called a Northing. Using a map with a 1000m grid, the first two digits are come from the large type on the label for the grid line to the south of the position. The last 3 digits are the distance in meters measured from the southern grid line. The MGRS standard states that "To facilitate machine-to-machine communication, an MGRS string is to have no intermediate spaces or punctuation marks and all the letters are to be capitals." I have not strictly followed this part of the standard in these tutorials. The inclusion of spaces to separate the logical parts of the coordinate string has been shown to facilitate the understanding and communication of coordinate strings between humans. I would encourage you to use spaces when writing MGRS coordinate strings, and to pause briefly between logical parts when communicating MGRS coordinate strings verbally. Truncated position formats for less precise positions The MGRS format is designed to support measurement precisions of 1m, 10m, 100, 1,000m, and 10,000m. by truncating the grid coordinate values. 10S GJ 06832 44683 - Locates a point within a 1 meter square 10S GJ 0683 4468 - Locates a point within a 10 meter square 10S GJ 068 446 - Locates a point within a 100 meter square 10S GJ 06 44 - Locates a point within a 1,000 meter or 1 kilometer square 10S GJ 0 4 - Locates a point within a 10,000 meter or 10 kilometer square 10S GJ - Locates a point within a 100,000 meter or 100 kilometer square When all of the coordinates you are working with are localized within the same 100,000 meter square identifier, it is permissible to drop the Grid Zone Designator and the 100,000 meter square id. 06832 44683 - Locates a point within a 1 meter square 0683 4468 - Locates a point within a 10 meter square 068 446 - Locates a point within a 100 meter square 06 44 - Locates a point within a 1,000 meter or 1 kilometer square 0 4 - Locates a point within a 10,000 meter or 10 kilometer square Note: It is easy to make an mistake using truncated position formats. Slipping a digit left or right results in a very different position. Worse, there is no visual clue that an error has been made, until the coordinate is plotted. Truncate, don't round When using less precise representation, it is important to truncate rather than round the Easting and Northing values. The Easting and Northing always refer to the southwest corner of the grid square. The size of square represented by a given coordinate will vary with the coordinate's precision. Truncating ensures the more precise squares will always remain within the less precise squares. Using various tools to plot and measure MGRS positions on a map Click on the tab for the tool style you want to know more about. Grid Style Tool Slot Style Tool Corner Style Tool Mini Corner Style Tool Map Ruler Style Tool Using a grid style tool to plot/measure a UTM position with 100m precision Using a slot style tool to plot/measure a UTM position with 10m precision Using a corner ruler roamer style tool to plot/measure a UTM position with 10m precision Using a mini corner style tool to plot/measure a UTM position with 10m precision Using a map ruler to plot/measure a UTM position with 10m precision See these tools in motion The interactive tutorial animates the same work on a real topographic map, with the coordinates written as MGRS. It starts where an MGRS coordinate starts — at the map's reference box, showing where the grid zone and the 100,000 meter square letters come from — before it ever touches a tool: Read the MGRS coordinate of a feature Plot an MGRS coordinate onto the map The practice map is drawn on NAD 27, so the tutorial also shows the datum tag that a non-default datum requires. Switch its Datum control to WGS 84 and both the answer and the tag change — see the two grids side by side. Learn more about... Map Datums and why they are so important Locating MGRS grid information on USGS topographic maps Grid Zone Details The 100,000 meter square identifier letter pairs Metric Distance Measurements The small differences between USNG and MRGS Some of the history behind the military adoption of UTM and MGRS More than you probably want to know... National Geospatial Intelligence Agency Standardization Document, Universal Grids and Grid Reference Systems (101 page pdf)

### MGRS History — UTM & MGRS Coordinate System History In 1994 a friend of mine made a request to the Pentagon for information on the origin of the UTM and MGRS coordinate systems.
https://maptools.com/mgrs_history

UTM & MGRS Coordinate System History In 1994 a friend of mine made a request to the Pentagon for information on the origin of the UTM and MGRS coordinate systems. My friend handed off the documents he received to me in 2015. I've scanned them into pdf files and had them retyped, so they would be both more readable and searchable. I've also replaced a missing page and line that's not in the pdf files. The documents received date from the 1940's and clearly show that the requirements of artillery gunners were the driving force in the design of map coordinate systems. Response from John W. Hager Geodesist with the Defense Mapping Agency A link to a pdf of the original document DEFENCE MAPPING AGENCY HYDROGRAPHIC/TOPOGRAPHIC CENTER SCIENTIFIC DATA DEPARTMENT GEOPOSITIONING DIVISION GEOPOSITIONING BRANCH V Details of the origin of the Military Grid Reference System (MGRS) have become obscure with the passage of time. The earliest information available in this office, the Study and Discussion of Military Grids, Probably early 1947, contains all the specifications of the Universal Transverse Mercator (UTM) grid. This study does not mention the MGRS. A memorandum from the Commanding Officer of the Army Map Service to the Chief of Engineers, 6 December 1946, (Encl 2 to the above study) gives examples of grid references. It is noted that the 100,000-meter grid square letters, an integral part of the MGRS, are not here used in the grid references. The letter from Brigadier Martin Hotine, Directorate of Military Survey , (Encl 3 to the above study) states that the specifications for a six-degree Transverse Mercator world- wide system were communicated to the British in October 1945. On 27 February 1948, the Joint Mapping Photography Committee Ad-hoc Committee on Universal Military Grid Referencing System proposed a grid referencing system containing all the specifications of the MGRS as it is currently used. The Joint Intelligence Committee (JIC) of the Joint Chiefs of Staff issued JIC Papers 410/1 and 410/2, approved 14 November 1949, prescribing the use of the Universal Transverse Mercator Grid, the Universal Polar Stereographic Grid and the Military Grid Reference System by all branches of the Armed Forced for joint operations use. AGAO-S 061.3 (28 Dec. 49) CSGID-M, Issued 29 December 1949 by the Office of the Adjutant General, Department of the Army, prescribed the use of those grids and grid reference system for the Department of Army. Army Map Service Technical Manual No.36, Grids and Grid References, January 1950, elaborated the details of the military grids and grid reference system. This was subsequently replaced by Department of the Army Technical Manual 5-241-1 , same title. The latest elaboration of these details is contained in Defense Mapping Agency Technical Manual 8358.1, Datums, Ellipsoids, Grids, and Grid Referencing Systems. JOHN W. HAGER Geodesist Brigadier Hotine's letter, London 1945 This is one of the early documents articulating the desire for a world-wide grid system. A link to a pdf of the original document Directorate of Military Survey, War Office. 12th November, 1945. To:- Colonel A.G. Matthews, Chief, Intelligence Division, c/o ST & D (RE) 1801 K Street N.W. Washington, D.C. Dear Matty, Many thanks for your letter of October 26th regarding proposed new world- wide grid systems. I think there can be no doubt that the polyconic is a bad military grid because it is not orthomorphic and does not therefore give the required degree of accuracy in rapid "plane" computations for range and bearing; or the same facility as an orthomorphic projection in rapid small instrumental surveys interpolated by "plane" methods. The present haphazard plaster of grids which has grown up all over the world (particularly in British areas of responsibility) is also a headache even though these are orthomorphic. They frequently lead to junctions in awkward places, although there is no reason to suppose that the junction bug- bear will be overcome by any cast-iron 6-degree system; or indeed by any grid system at all. The main point I think is that before we change at all we want to make quite certain that we are changing in the direction of the far future and not merely to meet some transient consideration. It is bound to be many years before we get on to a new system and we shall merely have had the vast labour and confusion for nothing if by then we have changed our minds again. We have been considering this matter at this end and have decided at any rate to try out a "mesh" system based upon the graticule rather that the use of a "plane" grid at all. The advantage of a mesh system are as follows: (a) It would obviate all grid junctions everywhere at any rate on the smaller scale maps. There would, however, be come discontinuity remaining on large scale maps across the boundary of disparate survey systems (e.g.:- the frontier of two countries) where fundamental geographic positions are not in sympathy. (b) It would vastly facilitate inter-service cooperation. The Navy, for instance, always work on some sort of graticule system of reference if they can and are only induced to accept "plane" grids for bombardment purposes under protest. The Air Force similarly hate grid junctions which always fall awkwardly for such purposes as fighter defense. Many anti-air defence systems cannot in any case operate across a grid junction, e.g.:- the use of "fruit machines" for vectoring defending aircraft. The question has for instance arisen in particularly acute form in relation to Coast Artillery which may otherwise be forced to switch at very short notice between no less than three grids; one for landward firing in support of ground operations; one for seaward firing in conjunction with the Navy; and one at the shortest notice for employment in an A.A. role. The disadvantages of a mesh system may be summarized as :- (a) Computations for range and bearing will not be simple, although it is likely that for the most rapid purposes the introduction of a scale factor in one direction will be sufficient: the value of the scale factor being suitably broadcast by, for instance, marginal information on maps. (b) All trig. lists would have to be cast into the graticule. We should no longer be able to use the results of foreign surveys neat in their own native projection. (c) The vast cost and probable confusion over a long period of time involved in any change. We are, however, trying out a mesh system in experimental areas in conjunction with the Artillery. I do not know what the answer will be but I certainly think that we must go into this much broader question in detail before we make any alteration whatever. If it is decided to stick to grid and to introduce a world-wide system then I think the six-degree Transverse Mercator proposal is as good as any. One advantage of it which has probably been brought to your notice is that the Russians do this and have adopted the six- degree belts of the International 1/1M map. The Germans were also proposing to do so, We get a considerable portion of the globe already covered for us on this system therefore (always assuming that we can get any data out of the Russians, which is doubtful). Conversely it may be considered an advantage to the Russians for us to facilitate their study of our surveys and to utilise them. This aspect of question very soon runs into deep water. Although the introduction of a world system of grids such as the Transverse Mercator proposal looks very tidy i doubt very much whether it would work out quite as tidily. A meridian boundary, in the nature of things must always ignore such factors as a grid junction falling awkwardly in a possible battle area and also such factors as the straight utilisation of National surveys, which of course are placed on a National projection rather than a purely geographic one. We might accordingly find that we had undertaken all the disadvantages of change for very little if we were to adopt such a stereotyped proposal. Another question that arises is the choice of a unit. We are likely to standardize on the metre of the grid systems. The main reason is that the British Army must accustom itself to training, and even maybe fighting overseas where it will frequently get foreign maps dished up with the least possible alteration in the shortest possible time. In the majority of the cases foreign material and trig. data would be in metres. There is moreover a growing world tendency (not as yet very evident in America) to get on to such an International unit as the metre for basic surveys, even though the common linear units of the country may be different. For instance the new surveys of Great Britain are coordinated in metres and all post-war O.S. maps will carry a metric grid. It would of course be a great advantage if we could both do the same but I do not know how you view the chances of getting the metre adopted for such purposes in America. At first I should not have thought the chances were very great. If we go on to a "mesh" system the question of degrees or grades or mils or possibly some other systems altogether will arise. It is necessary to have some decimal sub-division of angle for this purpose but the centesimal system works out too small and the mil works out too large as applied to latitude and longitude on the earth's surface. The sexagesimal minute is about right but is not decimally sub-divided, nor does it spring decimally from a parent unit. The answer may be to adopt, as the unit tens and decimals of sexagesimal minutes. We are adopting the latter for our preliminary trials. I will let you know this question progresses and shall be grateful for any further developments your side. I think it is important that we should keep in close touch with one another oven though we may not finally be able to adopt the same system. In fact I feel a little guilty about not having briefed you sooner. M.HOTINE Brig. D. Survey *COPY* STUDY AND DISCUSSION OF MILITARY GRIDS by Army Map Service and Military Intelligence Division, Office, Chief of Engineers, U.S. Army A link to a pdf of the original document STUDY AND DISCUSSION OF MILITARY GRIDS by Army Map Service and Military Intelligence Division, Office, Chief of Engineers, U.S. Army 1. Purpose of Study The purpose of the following study is to determine the characteristics required in a military grid and to select a system most nearly answering these requirements. Marked disadvantages are inherent in most grid systems now used. These disadvantages are complicated by the existence of many incompatible systems. 2. Existing Conditions 2.01. The polyconic military grid is prescribed by Section VII, AR 300-15, for use on all military maps of the United States. This system is laid out in zones 9 degrees wide in longitude with 1 degree of overlap between zones. It is so inaccurate at long ranges in certain directions that it cannot be used satisfactorily for the control of the fire of coast artillery weapons or heavy field artillery. 2.02. Because of this inaccuracy, the coast artillery harbor defense grid for area in the neighbourhood of the harbor defences in the continental United States is also authorized in paragraph 28, Change No.4, AR 300-15. This harbor defense grid system is a Lambert conic conformal designed particularly to serve the guns of the harbor defense concerned. It is not only not connected to the military grid system in the same area but is incompatible therewith. 2.03. Many other grid systems are in use not only in the Unites States but also in the rest of the world. Twenty states of the Unites States have adopted the state plane coordinate systems measured in feet and especially designed to serve the particular state in question. Each such system is hardly extensible beyond the borders of the state without the introduction of mater- ial inaccuracies. The enclosed map shows the overall picture of the grid systems used in allied military operations during the recent campaigns. (Incl. 1) 2.04. It is obvious that the presence of so many systems complicates map preparation and impose material confusing handicaps on actual combat operations. The presence of more than one grid system covering one area presents no particular problem in peace time or on manoeuvres involving but one arm. When the fog of war confuses men's minds, the presence of several coordinate systems in one area for use of different arms in fraught with potent opportunity for disasters resulting from uncoordinations attributed to mistakes in using the military grid. Involved in this matter are branch pride and branch stubbornness, each branch feeling justified in having a special grid system designed to the particular capabilities and needs of that branch. An example of this occurred in the United Kingdom whore the British coast artillery, Navy and Air Force covered the coastal area with three incompatible, incommensurable grid systems. Intolerable confusion which resulted from the use of these grids during the numerous German air raids in the Battle of Britain makes it highly probable that these conflicting systems would have led to at east a few local disasters has there been an invasion of Great Britain. 3. Basic Requirement 3.01. Primary Purpose of a Grid. The primary purpose served by the military grid on a map is to provide quick solutions to problems of distance and azimuth for the firing of weapons. It provides a quick simple means for referring to spot locations and for designating targets. It is an essential tool in coordination of military operations. 3.02. The coordination of the efforts of the many arms used on land, sea, and air, is a problem so complex as to make mandatory a single simple solution for problems of target designation and determination of range and azimuth. This requirement is believed to be so important in war that the use of a single system of limited but adequate accuracy is held to be better than the simultaneous use of two incompatible but otherwise more accurate systems. 3.03. The characteristics of the using arms and weapons which affect the design of the system to the adopted involve relatively little research. As a general rule, it has been assumed that permanently emplaced batteries will be more accurate in their fire than batteries temporarily emplaced in the fields. Therefore, the following table appears to provide sufficient criteria to determine the desirable accuracies of the grid system adopted. Probable Errors of Different Caliber Permanently Emplaced Guns at Ranges Shown ------------------------------------------------------------------------ Minimum Probable Probable Errors in Yards Relative Errors -------------------------------------------------------------- Range in 6" Gun 8" Gun 16" Gun Yards Range Defl. Range Defl. Range Defl. Range Deflection 10,000 22 2 68 3 18 3 1:555 1:5,000 15,000 35 4 70 5 28 4 1:535 1:3,750 20,000 52 6 73 8 40 6 1:500 1:3,333 25,000 68 8 77 13 52 7 1:480 1:3,571 30,000 83 19 63 9 1:476 1:3,333 35,000 73 10 1:479 1:3,500 40,000 80 10 1:500 1:4,000 45,000 *77 *7 *1:584 *1:6,428 ------------------------------------------------------------------------ * These values are appear unusual 4. Desirable Characteristics 4.01. Primarily a grid system should be accurate enough for all weapons and all military uses other than for very long distance missiles, should be quickly applicable to any previously ungridded native, map, should yield readily to simple computing methods and should provide simple numerical designators for location of targets. 4.02. Plane System. The system of coordinates desired is one with which all computations for the most accurate artillery firing can be simply yet accurately performed and especially one in which the integrity of angles is preserved. A mathematically exact graticule, such as that presented by the meridians and parallels, requires the use of geodetic functions to solve the spherical triangles involves, and entails a long, time-consuming complicated computation. Moreover, due to the convergence of the meridians, the arc of the parallel intercepted between any two meridians becomes shorter as the latitude increases. Complicated geodetic formulas would be necessary in the computation of any distance except one along a meridian. Complex fire control instruments would be needed, named by personnel highly trained in a branch of advanced mathematics. Neither the personnel, the instruments, nor the time are normally available. As a consequence, the system adopted should be one in which plane trigonometry can be employed in the solution of triangles. In such a plane system for general application to large area, the simplest and quickest computations can be secured through use of a grid network of equally spaced parallel and mutually perpendicular lines. 4.03. Grid Accuracy. A high degree of accuracy is, of course, desirable. However, grid accuracies which are greatly in excess of the accuracies for the most precise weapon using the grid appear to be neither necessary nor practicable. By reference to paragraph 3.03 above, it will be noted that the probable errors of artillery weapons are much greater in range than are their probable errors in deflection. The minimum probable error of permanently emplaced guns rarely is less than 1/555 in range and 1/5,000 in deflection. Consequently, a suitable military grid should be one designed to conform to these minimum probable errors. 4.04. Adaptability to Various Projections. The grid system selected should be adaptable for use of native maps without complicated recomputation or redrafting of that map. There are many map projections used in the making of large scale maps throughout the world. It is desirable to be able to overprint the adopted grid system on any or all of these projections without the introduction of errors in range and azimuth beyond that probable in good artillery practice. 4.05. Unit of Measure. Three general systems of linear measure are commonly encountered, on maps and in grids: the metric system, the so-called English system, and the nautical system. Mixtures of these systems unfortunately are prevalent. This matter is further complicated by the fact that three differing elements are involved - map quantities, grid quantities, and the quantities employed by using arms and weapons. a. Map quantities include azimuths, horizontal distances, contour intervals, and underwater depths. To the map user, the unit of measure in which horizontal distances on a map are expresses is not particularly important, as the conversion from map distances to ground distances is frequently done graphically against either an appropriately graduated bar scale on the map or range scale. However, the unit of linear measure used in the basic survey of the map may complicate the computation and compilation of trig lists for fire control. This latter operation is already quite complex due to the differing origins of longitude, datum planes, spheroids and schemes of projection, and other variations encountered in the native surveys of the world. Thus, the conversion from one unit of linear measure to another incommensurable unit adds an operation subject to mistakes and affecting final accuracies. b. Contour intervals and spot elevations should, but may not, be in the same unit of measure as the horizontal distances, in order to provide for the ready calculation of true slant ranges, defilade, mask, profile, etc. c. Underwater depths are generally expressed either in meters or in fathoms, although shoal water depths may be also expressed in feet. It is highly desirable that those units of measure be the same as the horizontal unit in order to be readily useful in the computation fo underwater profiles and beach gradients. d. The military grid, while essentially concerned with angles and horizontal distances, must be precisely related to the computed geographic positions. The necessary correlation between the vertical unit of measure and the horizontal unit of measure on the grid as indicated in b above, is essential for the quick solution of problems involving defilade, mask and true gun target distance. e. The using arms and weapons are not entirely coordinated in the units of measure employed in the laying of the piece. The Coast Artillery measures azimuths in degrees and hundredths of a degree from grid south as the origin. The Field Artillery measures angles in mils, with filed orientation of base circles. The Coast Artillery measures its range in yards, while the Field Artillery may measure it in yards or meters. Due to the tangent relationship of the mil, Field Artillery can readily transpose from angular measure to linear distance in either meters or yards. Each artillery weapon is served and laid by employing a multiplicity of tabular information, plotting tools, and gunner's instruments. All these things must be related to the unit of measure selected for map and grid quantities. At the present moment, due to the recent tremendous concentration of field artillery weapons in the European campaigns and to the use of the metric system throughout in that area, our Field Artillery is well equipped and trained in the use of the metric system. The Seacoast Artillery of the United States, including the Panama canal and Oahu, are not so equipped or trained. They use the yard-hundredths of a degree system, except in the coast defenses of San Diego where the coast Defense grid is graduated in feet rather than in yards. f. Existing Conditions. The majority of the large scale maps of the world are made on the metric system. Exceptions to this rule are the United States, Canada, Australia, United Kingdom, Union of South Africa, India, Melanesia, and Middle East. The following table shows the unit of measure of native maps and military grids employed in operational areas of the recent campaigns. MAP UNITS GRID UNITS ------------------------------------------- ------------------- AREA HORIZONTAL UNIT VERTICAL DEPTH UNIT GRID GRID TYPE (Map Bar Scale) UNIT (Map (Bathymetric UNIT Contour) Contour) ----------------------------------------------------------------------------- 1. France Meter Meter Meter Meter Lambert 2. Germany Meter Meter Meter Meter Trans. Merc. 3. Italy Meter Meter Meter ----- ----- 4. Tunisia Meter Meter Meter ----- ----- 5. Libya Meter Meter Meter Meter Trans. Merc. 6. Egypt Meter Meter Fathon Meter Trans. Merc. 7. Okinawa Meter,Cho Meter Meter Meter Unknown 8. Burma Miles Foot Fathom Yard Lambert 9. China Li,meter Meter Fathom Yard Lambert 10. Russia Meter Meter Foot Meter Trans. Merc. 11. Hawaii Mile Foot Fathom Yard Polyconic 12. Philipines Mile Foot Fathom Yard Polyconic 13. Poland Meter Meter Meter Meter Stereographic 14. Holland Meter Meter Meter Meter Stereographic 15. Belgium Meter Meter Meter Meter Bonne 16. Japan Meter,Cho Meter Meter Meter Trans. Merc. 4.06. Width of Zone. An inherent fault of any system of plane coordinates applied to the surface of a spheroid is the fact that inaccuracies increase as the zone is extended east and west or in other cases, as the belt is extended north and south. It is also desirable, although not entirely necessary, to keep at a minimum the deviation of grid north from true north. This deviation likewise increases materially as the distance from the central meridian increases. These inaccuracies can be kept within reasonable limits by the adoption of narrow grid zones. It has been stated only semi-facetiously that there are three military engineering axioms: a. It always rains in war. b. It's always too cloudy to get aerial mapping photographs. c. Battles are always fought on grid junctions. This Inst axiom is spoken from the depths of bitter experience, rendering it obvious that a grid zone should include as much area as possible so as to obviate too frequent junctures between grid zones on the battlefield. However, this desirable criterion cannot be widely applied without including intolerable inaccuracies of the grid. Elimination of the undesirable features consequent upon fighting a battle on a grid juncture can be partially accomplished by providing for overlap between grid zones. The 9 degree width of the military grid system presently prescribed for use in the United States introduces appreciable inaccuracies near the edges. A reduction in width to 6 degrees betters this situation materially. The computation of ranges and azimuths where the gun position is located in one grid zone and the target in another can be provided for by a half degree overlap between grid zones, enabling the coordinates of the gun zone to be extended a half a degree into the grid zone in which the target is located. 5. Comparison of Grids 5.01. Polyconic Grid. For military purposes, a grid may be regarded as a set of perfect squares ruled on a plane map, scale 1:1, and then transferred to the earth's surface. Evidently after being transferred to the earth's surface the squares will no longer be perfect; and distortions they will have received in being put on the surface of the earth will reflect the distortions of the projection used for the map. a. The polyconic projection is defined as one which the central meridian and all parallels are mapped to scale and with true curvature. All other lines are stretched, the amount increasing as the square of the distance from the central meridian, and being greatest for north-south lines. Angular errors also appear, increasing with distance from the central meridian. Of course it is possible to compute these errors, at least roughly, and to allow for them, and this is regularly done by engineer survey troops. But the corrections are generally considered beyond what is to be expected of artillery units in the field, and for that reason all mention of them is omitted in artillery technical manuals, even when survey procedures are discussed. It is proper, therefore, to compare the errors of the projection as shown in the following table, directly with the errors of the guns (Section 3.03). Errors of U.S.Military Grid at 4°30' from Central Meridian, and 30° Latitude ------------------------------------------------------------------------------------------------- | | | True | True Azimuth 0° | True Azimuth 45° | Azimuth 90° True |----------------------------|-----------------------------|---------------------------- Range | Range Rela- | Defl. Rela- | Range Rela- | Defl. Rela- | Range Rela- | Defl. Rela- (yds) | Error tive | Error tive | Error Defl. | Error tive | Error tive | Error tive | (yds) Error | (yds) Error | (yds) Error | (yds) Error | (yds) Error | (yds) Error ---------|--------------|-------------|--------------|--------------|--------------|------------- 10,000 | 23 1:435 | 0 0 | 12 1:836 | 12 1:836 | 0 0 | 0 0 30,000 | 70 1:428 | 4 1:7500 | 35 1:859 | 35 1:859 | 0 0 | 0 0 40,000 | 70 1:428 | 4 1:5000 | 47 1:850 | 47 1:850 | 0 0 | 0 0 It is evident that at 40,000 yards, and an azimuth of 45°, the error of the grid in deflection is almost five times the probable error of a 16-inch gun. Errors of the above amount are characteristic of the s0-called non-conformal projections, i.e., those in which the shaped, as well as the scale of small areas is distorted. Such non-conformal grids were widely used prior to World war I, but most of them have been abandoned in recent years, chiefly, no doubt, because of the breakdown of the old French Bonne grid during the War. In addition to its lack of comformality, the polyconic projection possesses the disadvantage that it has not been studied thoroughly from a mathematical standpoint. Hence the small corrections needed for precise surveys are not known; the transformation from other grids to be polyconic is not known; not even the transformation from one polyconic belt to another has been studied. b. So far as grid junctions are concerned, the polyconic is theoretically excellent; it can be extended indefinitely both north and south, so that the world can be divided up into meridianal strips. In practice, the present World Polyconic has two latitudinal junctions, one near 24°, due to failure to put the origin of the old U. S. grid sufficiently far south; the other is near 49°, and is due to inaccuracy in the old tables which amounts to 1.1 meters. c. The polyconic grid is not well suited for foreign maps due to its lack of conformality. By the older laborious hand methods of grid plotting, this introduced no difficulties other than laborious calculations; but the use of the coordinatograph, for rapid plotting of grids and projections, requires a conformal grid. 5.02. Cassini-Soldner Grid. This is a non-conformal grid, very similar to the polyconic, and open to the same objections. It differs only in that the grid east-west lines, rather than the parallels are represented to true scale and with true curvature. 5.03. The Bonne Grid. Both meridians and parallels are represented to true scale on the Bonne projection; the error shows up on lines which run NE to SW, or NW to SE. It is just as bad as in the case of the other non-conformal projections; and this projection has been generally abandoned. 5.04. The Stereographic Grid. The stereographic grid may be briefly defined as a conformal grid (that is, one having zero angular distortions for small distances, and very small angular distortions for any distance) in which the scale error is Zero on a standard circle. This grid is conformal insures that within about 200 miles of the center- point, the error in deflection will be less than the error of the most accurate guns. The range error is considerably larger than the deflection error , but is considerably less than the range error of permanently emplaced artillery. Unfortunately, this grid cannot be extended more than 300 miles from its center point and grid zones are circular in Shape. It is quite suitable for small roughly circular countries such as Poland, Holland or Romania, which use it ; but on a world-wide basis It would lead to a great multiplicity of grid junctions, and points where three or more grids meet could not be avoided. 5.05. Lambert Grid. Like the stereographic, the lambert is a conformal projection. It may be defined as a conformal projection in which the scale errors are zero along two parallels . It is well suited to the mapping of moderately large areas , and has been extensively used by the British and French, especially in recent years. The numerical values of the errors are similar to those for the Transverse Mercator given in the next paragraph. The errors are very small in deflection, as in necessary for artillery grid. It is readily adaptable to gridding maps On other projections. In general a slight change of scale only would be Required. On the other hand, the rapidly increasing grid declination makes it impracticable to extend the grid more than 15° from the central meridian (except along the Equator , where grid declination is always zero). For this reason, the British and French were forced to introduce numerous zones, and to permit junctions of three grids at the same point. These numerous grid zones necessary, both north-south and east-west, make the Lambert undesirable for extensive coverage 5.06. Transverse Mercator Grid. The Transverse Mercator grid may be defined as a conformal grid in which the central meridian is represented by a straight line at true scale. it is well suited to largo areas, and is being used by the Germans, Russians, British, and Japanese. The errors at a given point vary little in all azimuths and average values for different ranges are given in the following table for 30° north latitude and for 3 1/2° from the central meridian. ------------------------------------------------------------------- | | Transverse | Transverse | | True | Mercator Grid | Mercator Grid | | Range | Range Relative | Deflection Relative | | (yds) | Error Error | Error (yds) Error | | | (yds) | | |--------|-----------------------------|--------------------------| | 10,000 | 10 1:1000 | 0 0 | | 30,000 | 30 1:1000 | 3 1:10000 | | 40,000 | 40 1:1000 | 5.8 1:6900 | |--------|-----------------------------|--------------------------| Obviously, the grid is well suited to artillery purposes since the inevitable errors ere thrown into range rather than deflection. The grid can be extended indefinitely in latitude like the polyconic. Hence it never necessary to have a grid junction involving more than two grids (except, of course, near the Poles). Transformation of coordinates from one bolt to another can be done by a formula already worked out. The formula is always the same, and is very simple in character. The grid declination will remain moderate throughout the belt. The grid can be readily adapted to use on other projections. Much theoretical work has already been done on this subject by a large group of mathematicians, including especially Professor W. K, Hristow. Extensive computations, especially for the Balkan countries, were done by the German High Command (O. K. H. ) during World War II which could, in an emergency, be promptly utilized if the proposed projection is adopted. In addition, much geodetic data of foreign areas on file at Army Map Service are on this system. The projection is well suited for converting data on various spheroids to a common basis. Transverse and lower orders of triangulation may be computed and adjusted directly on the grid due to its conformality. This feature, which is a large saving in field and office, is not practicable where a non-conformal projection such as the present Polyconic is used. 5.07. Tabular Comparison of Grids. ____________________________ -------------------------------------------------------------------------------------- GRID SYSTEM APPLICABILITY GRID MAXIMUM MAXIMUM TO FOREIGN MAPS** JUNCTIONS RELATIVE RELATIVE RANGE ERRORS* DEFLECTION (45,000 yds) ERRORS* (45,000 yds) -------------------------------------------------------------------------------------- Polyconic Very Poor Few & simple 1/1228 1/2454 Cassini-Soldner Very Poor Few & simple 1/1228 1/2454 Bonne Very poor Many & complex 1/2454 1/615 Stereographic Good Many & complex 1/2454 1/15,360 Lambert Good Many & complex 1/2416 1/7,663 Transverse Mercator Excellent; much work already done Few & simple 1/2416 1/7,663 --------------------------------------------------------------------------------------- ** A grid system is considered applicable to a foreign map if it can be put on most maps without changing map or grid except in scale. * Range and deflection errors are maximum values within 160 miles from the center of the projection, whether the center is a line, as in the Transverse Mercator, Lambert, Cassini-Soidner, and Polyconic, or a point as with the other two. The figures are based on GSGS "Survey Computation". 160 miles is the approximate distance (at 40° of latitude) from the center of the proposed Transverse Mercator zones to the junctions, about 3° of longitude. The actual maximum errors of the present world Polyconic grid are considerably larger, since the grid zones are 9° in, width. 6. Conclusions as to System to be Adopted. 6.01. The Lambert Orthomorphic projection is conformal but is not suitably as it requires grid zone junctures both north and south and east and west. The polyconic grid system now prescribed for use as military grid on all maps of IJ. S. is inaccurate in both azimuth and distance. The greater inaccuracy is in azimuth and is more than the probable error in deflection of permanently placed guns. The transverse mercator grid is conformal and is immediately applicable without plottable error, to the majority of the map projections commonly encountered on the native maps of the world. The transverse mercator grid reduces inaccuracies to a point where they are compatible with the accuracies required by all modern artillery weapons. This grid is sufficiently accurate to eliminate the necessity for a special Coast Artillery grid in the vicinity of coast defense locations. 6.02. In view of the foregoing, a military grid system based on. the transverse mercator projection applied to the local spheroid and measured in meters, or in the standard unit of the country concerned, should be applied in zones running from Latitude 80° N to Latitude 80° S, 6 degrees of longitude wide, with one degree of overlap (1/2 degree each side). The latitude of the origin is the equator. (Incl #2). The false casting to be applied for each zone would be 500,000 meters or yards. Scale factor on the C. M. should be 0.9996. The zones should be numbered, commencing with Zone 1, with its western edge at 180° longitude, running east to 174° west longitude. Consecutively numbered zones continue eastward by successive steps of 6 degrees until reaching the point of beginning; these number designations being identical to the I.M.W 1:1,000,000 layout. It will be noted that in certain countries where the native maps use the English units in elevations. and contours, such as the U. S., Canada, Australia, India, the proposed grid system should be graduated in yards rather than meters. In certain training areas in the U. S., both metric and yard grids will be required for training purposes. Where the metric Grid is used in the domestic U.S., the spot elevations should be in meters and the contours should be converted to a metric interval, provided that such conversion of contours shall be limited to those maps to be used for metric training purposes. 7. Proposed Specifications Projection: Transverse Mercator. Spheroid: Same as that used to compute the triangulation of the area. Unit: Meter in most areas; yard in U. S. and other areas where the English system is firmly established. Central Meridians: 3°E (or W) of Greenwich and every 6° thereafter. Latitude of Origins: 0° False Easting: 500,000 meters (or yards) . False Northing: 0 for Northern hemisphere 10,000,000 for southern hemisphere. Scale Factor: 0.9996 Zone Width: 6° of longitude (plus 1/2° overlap at each edge) Limits of Zones: North 80° latitude South: 80° latitude Zone Numbering; Commencing with Zone 1 east of 180° longitude, and continuing easterly around the earth. (Identical to I. M. W. system designation) Limits of Tables: North: -80° latitude South: -80° latitude 8. Implementing Actions and Costs 8.01. It should be noted that the application of the transverse mercator grid system should be progressive rather than instantaneous. Priorities for conversion are indicated as follows: a. Military areas in the United States, b. Mapping and map revision of foreign areas embraced in the 20-year strategic mapping plan approved by the War Department. c. General areas of the United States as stocked by the Army Map Service. d. Other maps of foreign areas as reissued. Upon the issue of the new map in any area, the new grid will normally be shown in full, but to safeguard against the event of the occurrences of an emergency while a series is still in a state of partial conversion, the maps will carry marginal marks to permit easy plotting and overprinting of the old grid. 8.02. Since Amy Map Service and map depots in the theaters now hold extensive stocks of maps carrying the expedient war-time grids, It is to be expected that the proposed standardization of the transverse mercator grid automatically renders obsolescent these stocks. The cost of a conversion in this respect is estimated as follows: a. Cost of conversion of points and correction of drafting copy (1) United States areas $99,500 (2) European areas $103,000 (3) Other overseas areas $22,000 b. Cost of replacement of stocks to be retired (1) United States areas $ -0- (2) Overseas areas $10,000 Since all United States maps are to ho converted to military scales (1/25,000, 1/50,000), new stocks are to be prepared in any event. Overseas accumulation of war time maps, it has been reported, are being salvaged except for small reserves which will probably not be replaced. The $10,000 figure should be ample to provide for all requisitions directly attributable to the change in grid. The cost of now authorizing the proposed conversion is properly to be weighed against the much greater cost that would be borne should circumstances require the conversion ten years hence. The conversion must ultimately be made in view of the inadequacies of the present medley of grids to suffice for the anticipated requirements of another war. It is considered unquestionable that the cost of the conversion should be accepted now if it be agreed By the General Staff that the transverse mercator grid is in fact the correct design for the future, based on what can now be discerned as to future characteristics requirements. 8.03. It is suggested that the views of the Navy Department be obtained prior to final standardization in view of the application of the military grid to maps and charts for amphibious operations. It would also be desirable to coordinate the design so far as possible with the Director of Military Survey, War Office, London, who has expressed his general views in an informal letter (Incl. #3). ARMY MAP SERVICES Recommendations for Military Grids 6 December 1946 A link to a pdf of the original document ARMY MAP SERVICES Corps of Engineers, U.S. Army 6 December 1946 MEMORANDUM TO: Chief of Engineers SUBJECT: Recommendations for Military Grids 1. Included herein are certain recommendations for grid numbers and grid references. A pertinent discussion and background information follows each recommendation. 2. The Universal Transverse Mercator Grid supersedes approximately 85 previously used grids which made up an undesirable heterogeneous system. This modernization should be further expanded to revise the outmoded standards for grid numbers and grid references which were designed primarily for fire control purposes only. The inadequacy of the present system for use in making general grid references became apparent during the past war. To satisfy their needs it was necessary for the individual theater commanders to devise new methods to fill this deficiency. There was an unfortunate lack of consistency for the systems used varied with the theater. Before formulating these recommendations an exhaustive study was made of all the war-time provisional systems. The best of each is incorporated within these recommendations, which if adopted would assure a standard but simple fool-proof system, designed, at the same time, to accommodate changing techniques in warfare. 3. GRID INTERVALS a. RECOMMENDATION - It is recommended that grid intervals be: Maps 1:5,000 and larger 1,000 yards (or meters) with grid lines ticked at 100 yard (or meter) intervals. Maps 1:10,000) 1:25,000) 1,000 yards (or meters) 1:50,000) Maps 1:100,000) 1:250,000) 1,0000 yards (or meters) b. The grid intervals authorized at present are: Maps larger than 1:5,000 100 yards Maps 1:5,000 to 1:63,360 inclusive 1,000 yards Maps smaller than 1:63,360 to larger than 1:100,000 5,000 yards Maps 1:100,000 to larger than 1:400,000 10,000 yards Maps 1:400,000 to 1:500,000 inclusive 50,000 yards c. The intervals of British grids are: Maps larger than 1:5,000 100 meters (or yards) Maps 1:5,000 to 1:100,000 inclusive* 1000 meters (or yards) Maps smaller than 1:100,000* to 10,000 meters (or yards) 1:500,000 d. It is noted that according to the new edition of AR 300-15, authorized map scales are: Small scale (1:1,000,000 Medium Scale (1:250,000 (1:100,000 Large scale (1:50,000 (1:25,000 (1:10,000 (1:5,000 e. The war proved that generally the British grid intervals were superior. The U.S 5,000 yard interval was awkward and confusing in as much as the abbreviated reference for a common point on maps of different scales would be dissimilar in all instances. Authorization should be granted to revise the grid intervals to overcome this defect and to make them more compatible to the revised authorized map scales. 4. GRID REFERENCES a. RECOMMENDATION - To satisfy particular needs two types of grid references should be made standard: general references, and fire control references. (1) General reference - Such a reference should generally consist of the grid zone designation by a group of numbers expressing the E and N coordinates of the referred point; examples: 30 NC 80432864 27 SF 69143872 (1,000 unit reference) 30 NC 804286 27 SF 691387 (10,000 unit reference) ----------- *In all except Europe, AMS sheets of 1:100,000 falling in British Grid areas were gridded at 10,000 meter (or yard) intervals (a) Grid zones 1. Zones for the Universal Transverse Mercator grid are identified with the IMW column (6° E-W) numbers, starting at the international date line (180° meridian) and reading 1 to 60 in an easterly direction. (See attached index). To prevent similar references for points 1,000,000 units apart (north-south) the IMT row letters preceded by N (for north) or S (for south) should be incorporated within the system and added to the zone number designation. Under the IMW plan, each row (4° N-S) is assigned a letter of the alphabet starting from the equator, preceding in both directions. 2. To assure proper identification each sheet should carry in its grid reference box its complete zone identification. 3. Within an area assigned to an army the grid zone designation may be deleted at the discretion of the Commanding General for reporting within the grid zone providing sender and receiver are not more than 500 miles apart in a N-S direction. (The zone designation is necessary in such a case since the numerical reference is the same at 1,000,000 units in a N-S direction). For reports to higher headquarters, however, the complete reference must be given. (b) Numerical reference - To facilitate making such references from a 1,000 unit grid, a reference should be simply an eight digit number; for example: 80472866. The "804" represents the 100,000, 10,000 and 1,000 digits of the easting grid line to the west of the referenced point, the "7" represents the estimated tenths from the easting grid line to the point, the "286" represents the 100,000, 10,000 and 1,000 digits of the northing grid line south of the referenced point, and the "6" represents the estimated tenths from the northing grid line to the point. To maintain a relationship between similar grid references from different scale maps, a reference from a 10,000 unit grid should be a six digit number; for example: 804286. The "80" represents the 100,000 and 10,000 digits of the easting grid line to the west of the referenced point, the "4" represents the estimated tenths from the easting grid line to the point, the "28" represents the 100,000 and 10,000 digits of the northing grid line south of the referenced point, and the "6" represents the estimated tenths from the northing grid line to the point. (2) Fire control references to be used within the sphere of the equivalent of one adjacent 1:50,000 sheet in all directions (two 1:25,000 sheets, four 1:10,000 sheets, etc.) - Existing methods for determining grid references for fire control as outlined in FM 6-40, Part Four, Chapter 2, should be retained with but one modification: Sheet name designations should never be used. When a grid reference is being sent to a station outside the sphere of the equivalent of one adjacent 1:50,000 sheet in all directions (for example: a long range gun), then the full grid reference should be sent preceded by the zone designation (see (1) above); for example: 30 NC (804.72-1286.68) b. Existing regulations (See FM 6-40, Part Four, Chapter 2) designate the following methods for reading a grid reference: (1) Designation of sheet, parenthesis, X coordinate, decimal, location to nearest yard, a dash, Y coordinate, decimal, location to nearest yard, parenthesis. Example: Annapolis (804.729-1286.684) (2) When the map is definitely understood, its designation may be omitted. Example: Annapolis (804.729-1286.684) (3) If the location to the nearest 10 or nearest 100 yards only is desired, or if the measurements cannot be made with greater accuracy, the digits indicating units or tens may be omitted. Examples: (a) (804.72-1286.68) to nearest 10 yards (b) (804.7-1286.7) to nearest 100 yards (4) For expediency it is permissible to include only two digits to the left of the decimal point (10,000 and 1,000 digits), omitting any preceding digits. Examples: (a) (04.729-86.684) (b) (04.72-86.68) (c) (04.7-86.6) (5) If the point is fixed within an area 10,000 yards square, only one digit need be given before the decimal point of each coordinate. Examples: (a) (4.729-6.684) (b) (4.72-6.68) (c) (4.7-6.7) (6) If a large number of points are being designated by the abbreviated coordinates shown in example (c), the decimals and dashes may be omitted and the reference given as (4767). c. References for British Grids are read according to the following methods: (1) Maps bearing a 10,000 unit interval (1:100,000 to 1:500,000); letter of 500,000 unit square (written as a small capital letter), letter of 100,000 unit square (written as a large capital letter), 10,000 digit of easting line to the left of the point, estimated tenths (1,000 units) eastward to point, 10,000 digit of northing line south of the point, estimated tenths (1,000 units) northward to the point. Example: cA1428 This locates point to nearest 1,000 units. (2) Maps bearing a 1,000 unit interval (1:5,000 to 1:100,000 inclusive): Letter of 100,000 units square, 10,000 and 1,000 digits of easting line to left of point, estimated tenths (100 units) eastward to point, 10,000 and 1,000 digits of northing line south of the point, estimated tenths (100 units) northward to the point. Example : A143286 This location point to nearest 100 units. d. During the war, the Pacific and Southwest Pacific Commands found it feasible to use a system for reading general grid references similarly to that used with British Grids. Apparently, a broad interpretation of existing regulations was made to find authority for the change. The name of the map is not mentioned (authority: see 4 b (2) above); digits to the left of the 10,000 and 1,000 unit digits are omitted (authority: see 4 b (4) above); decimals and dashes are omitted (authority: see 4 b (6) above). (1) To read a reference point on a map employing a 1,000 unit interval read: the 10,000 and 1,000 digits of the casting line to left of point, estimated tenths (100 units) eastward to point, the 10,000 and 1,000 digits of the northing line south of the point, estimated tenths (100 units), northward to the point. Write as a 6 digit continuous number. Example: 143286 (2) A similar procedure is followed in reading a reference on a map using a 10,000 unit interval, except that the digits for the grid lines are for the 100,000 and 10,000 units (the last four digits being omitted) and the estimated tenths represent 1,000 units. Thus, a reference for the same point cited in (1) above, might read: 214128 e. Discussion of recommendation (par. 4 a (1), above) for: General references. (1) Experience in the Pacific Theater proved that general grid references were frequently used. Usually it was unnecessary that these general grid references possess the same accuracy as that required for fire control purposes. It was deemed sufficient to identify any general grid reference to the nearest 1/10th of the grid interval (i.e., 100 units at a 1,000 unit grid interval; 1,000 units at a 10,000 unit grid interval). The system which employed a continuous six digit number as a grid reference (example: 143286) proved highly successful. Its principal merits wore simplicity and intelligibility. The standard method for reading grid references )see par. 4 b (1), above) was primarily designed for fire control purposes and when used for general purposes becomes very awkward. This was the experience in the Pacific Theater which found that sheet name designations, parentheses, decimal points and hyphens were superfluous and only increased the time necessary to reading and sending general grid references. (2) There were two faults with the Pacific system: danger of confusion between a reference taken from a map bearing a 1,000 unit interval and from one of a 10,000 unit interval, in as much as both were six digit numbers; and lack of connection between references for a common point taken from a 1,000 unit grid and from a 10,000 unit grid, in as much as in reading a reference from a 1,000 unit grid the principal digits were the 10,000 and 1,000 ones and for a reference from a 10,000 unit grid the principal digits were the 100,000 and 10,000 ones. Thus, references for a common point might read: 047866 (from a 1,000 unit grid) and 804286 (from a 10,000 unit grid). (3) Under the ANS proposal these faults would be eliminated. An eight digit reference would immediately be recognized as being from a 1,000 unit grid, and a six digit as being from a 10,000 unit grid. Further, a coordination would exist between references from different unit grids for common points, as: 80432863 (reference from 1,000 unit grid) 804286 (reference from 10,000 unit grid) (4) Normally, under the system as proposed it is required that in referring a point the entire reference be given - grid zone designation and numerical coordinates. In reporting in a single grid zone between points not more than 500 miles apart in a N-S direction designation of the zone is unnecessary. Consequently, if he is certain that no confusion will result, the theater commander should be permitted to issue instructions to omit the zone designation from grid references. However, in reporting to higher headquarters, between grid zones, and between points in the same grid zone, more that 500 miles apart in a N-S direction, the grid zone designation should never be omitted. The 500 mile rule is required since a reference will read the same for points which are 1,000,000 units apart in the same grid zone. (5) With the new type of warfare in which activities are far-flung it is important that references given in communications identify the area. The use of a sheet name as presently required by regulations is inadequate for the receiver would generally expand too much time searching map catalogues and indices to identify the locale of the sheet. To introduce such a reference with only the designation number of the grid zone would require the use of 1,000,000 digits in the numbers. This is not desirable as it would mean that the numerical reference would differ from that used for a local general reference, and would also require the use of decimal points and hyphens since the 1,000,000 digit might occur only with one coordinate. The solution is to introduce such a grid reference with the designation number of the grid zone followed by a sub-zone letter designation. (See paragraph 4 a (1) above). This makes an absolute identification. Its use would simplify the overall grid reference system in that the numerical reference would be the same for both an abbreviated general local reference and for a reference used in official communications to higher headquarters. The use of the sub-zone letter designation does not create a new system but makes complete utilization of the entire IMW numbering system whose row numbers are the basis of the numbering of the zones of the Universal Transverse Mercator Grid. (See attached diagram). f. Discussion of recommendation (par. 4 a (2), above) for: Fire control references - The system presently in use is generally quite adequate for its purpose. However, it is deemed more desirable to use grid zone designations instead of sheet identifications. (For arguments see paragraph 4 e above). 5.GRID REFERENCE BOX a. RECOMMENDATION - It is recommended that the grid reference boxes used in foreign areas on AMS maps be made standard practice for use on all maps including areas in the United Stats. The grid reference box should contain instructions for determining a general reference. b. The inclusion of a grid reference box in the margin will assure standard renditions of grid references, eliminating any reference to military manuals by personnel unfamiliar with grids. c. It is felt that grid references for fire control come within the category of special purpose and are not as widely used as general grid references as they generally are limited to artillery use. Consequently, the method of determining such references need not appear in the grid reference box but should be explained in proper military manuals (see par. 7). If considered necessary, reference to such manuals could be included in the grid reference box. 6. GRID NUMBERS a. RECOMMENDATION - It is proposed that a modification of the so-called Canadian Grid Numbering System be made standard on all maps published by the Army Map Service. Under the system, grid numbers would appear on all four sides of a sheet labelling each grid line, and "principal digits" would be shown on the face of the map labelling each grid line, appearing east or north of every accentuated grid line (every even tenth line - 10,000 on a 1,000 unit grid and 100,000 on a 10,000 unit grid). On a 1,000 unit interval grid except for the values shown in the southwest corner the last three digits of each grid number are omitted and the principal digits (100,000, 10,000 and 1,000) appear larger than the 1,000,000 digit; for example: (corner) 1 276 000 yds. 1 277 1 278 Numbers for a 10,000 unit grid appear in a similar manner, except that the last four digits odf wach number are omitted; for example: (corner) 1 27 0000 yds. 1 28 1 29 b. Existing standard practice requires that on grids of intervals of 1,000 units the last three digits be omitted and that on grids of 10,000 units the last four digits be omitted. Regulations do not specifically limit the appearance, frequency or location of the numbers. c. The advantages of this numbering system are apparent: the numbers on the face of the map materially aid the map user in reading the grid and in determining references; the use of superior type around the border accentuates the principal digits (100,000, 10,000 and 1,000) materially aiding the map user in making general grid references. d. Under the system used in the Pacific for 1,000 unit grids, numbers appeared on all four sides of the sheet labelling each grid line. The last three digits of each number were omitted and the principal digits (10,000 and 1,000) appear larger than the 1,000,000 and 100,000 digits, as for example: (corner) 12 76 000 yds. 12 77 12 78 The principal digits also appeared on the face of the map labelling each grid line appearing at 10,000 unit intervals east or north of every 10,000 unit grid line (which are accentuated in weight). The modification to this system recommended in a, above, is necessary since the 100,000, 10,000 and 1,000 digits would appear in a grid reference as recommended in par. 4 a (1), above. 7. GRID MANUALS a. RECOMMENDATION - Subject to approval of the recommendations appear- ing in the preceding paragraphs, a recommendation is made that the Army Map Service be directed to prepare a new military manual covering the subject of grids, and to prepare the text necessary for any revisions to existing manuals. b. Investigation reveals that no military manual covers the subject of military grids completely. This is a serious omission and should be remedied. 8. It is felt that the above recommendation will materially improve the use of our grid system. The needs of the various grid users are provided for; a standardization is effected; and full use is made of knowledge gained through experience during the past war. W.H. MILLS Colonel, Corps of Engineers Commanding Officer. Chairman of JMPC Ad-hoc Committee on Universal Military Grid Referencing System A link to a pdf of the original document 27 February 1948 FROM: Chairman of JMPC Ad-hoc Committee on Universal Military Grid Referencing System To: Colonel Northrup, U.S. Army Captain Hobbs, U.S. Navy Colonel Tison, U.S. Air Force Reference: (a) JIC 410/M of 23 January 1948 Enclosure: (A) 1. In accordance with directive contained in par. 1 of reference (a), a committee consisting of Colonel Mills, Commanding Officer, Army Map Service (Chairman), Mr. Bloom of the Aeronautical Chart Service and Mr. Medina of the U. S. Hydrographic Office has devised a universal military grid referencing system which it considers suitable for the Armed Forces. 2. This is submitted for consideration. Enclosure (A) contains complete information on the system. It is requested that this proposal be transmitted to the operating forces for study. 3. Should the Army, Navy or Air Force believe that there is another system more suitable than that described in Enclosure (A), complete information regarding such a system should be submitted to this ad-hoc committee for investigation and consideration. 4. In view of the urgency for an early decision, action should be expedited. Approval, or any recommended changes, are desired by 15 April 1948. W. H. MILLS Colonel, Corps of Engineers Chairman, JMPC Ad-hoc Committee on Universal Military Grid Referencing System Copies: Navy: 25 Army: 50 AF: 25 Lt. J. R. Phillips, JMPC: 1 Joint Mapping Photography Committee Ad-hoc Committee on Universal Military Grid Referencing System A PROPOSED STANDARD UNIVERSAL MILITARY GRID REFERENCING SYSTEM 1. INTRODUCTION There is a mandatory and urgent need for a standard referencing system, for use by the Armed Forces.Such a system must have the following outstanding characteristics: a. It must meet the individual and collective requirements of the Army, Navy and Air Forces in such a way that all services speak the same language. b. It must insure positive identification of any point in the world, without danger of ambiguity,particularly at spheroid and datum junctions. c. It must be simple of understand, brief and capable of being abbreviated either for large-scale or for local operations; and adapted to the requirements of fighter pilots traveling at high speed. d. It must be suitable for rapid computations of range and azimuth, with the required accuracy. e. It must be usable in Polar areas. f. It must avoid difficulties arising from the reversal of sign at the 0 and 180th meridians and Eqautor. 2. PRESENT SITUATION a. Section IV, W.D.Circular No.33, 5 February 1937, establishes the Universal Transverse Mercator Grid as the official grid for the Department of the Army. Accordingly, all maps published by the Army since 5 February 1947 bear the UTM Grid. In the interests of consistency, the U. S. Hydrographic Office has also surprinted the UTM Grid on all approach and bombardment charts, and on all hydrographic charts designed for use in amphibious training exercises. The UTM Grid supersedes an undersirable heterogeneous system which included the World Polyconic Grid, the U. S. Polyconic Grid, the Panama Grid and approximately 80 so-called British Grids. Since the projection of the grid is conformal, the grid can normally be applied to map constructed on any the standard projections. (I) ---------------- I The merits of the UTM Grid and deficiencies of the others are discussed in Appendix I. b. The following are the grid referencing systems which are authorized and/or presently in use by the various armed forces(2); none can satisfactorily fill the requirements for a universal system as outlined in paragraph 1, above: (1) Fire Control Referencing (FM 6-40, 1 June 1945, Chapter 2, Section 1 , pp.163-164: also, see Appendix II-I): This is the system presently authorized for use by the Army. (a) Advantages: The system is suitable for rapid computations of range and azimuth;no difficulties arise from the reversal of sign at the 0° and 180° meridians and at the Equator. (b) Deficiencies: Designed originally for fire control use by the Army, it does not fill the needs of the Air Force and the Navy; it is not adaptable to world wide use; it does not provide for spheroid junctions; while it allows for abbreviation for large scale activities; it does not provide for referencing in the polar areas; it is lengthy and awkward due to use of sheet-names, decimals, hyphens and parentheses. (2) Pacific World War II Practice (see Appendix II-2): Finding the authorized referencing system inadequate, the commanders of the Pacific Theaters devised a new system to fit their needs. This was a compromise between the Fire control and British Grid referencing systems. To a certain degree, this alleviated but did not eliminate the deficiencies of the authorized system. (a) Advantages: The system is suitable for rapid computations of range and azimuth;no difficulties arise from the reversal of sign at the 0° and 180° meridians and at the Equator; a reference is brief and not complicated with decimals,hyphens and parentheses. (b) Deficiencies: While fairly satisfactory for the local needs of the Army an Navy, it did not fill the needs of the Air Force: it is not adaptable to world wide use; it does not provide for spheroid junctions; it does not provide for abbreviation; it does not provide for referencing in polar areas; while the awkwardness of the authorized system was eliminated, ambiguities in reporting outside grid zones could result. (3) British Grid Referencing (TM 44-225, section IX, pp. 70-72; also, see Appendix II-3): By agreement, U. S. Forces used the British Grids wherever they existed. ______________ 2 Regulations also provide for the Point Designation Grid (TM 44-225, 30 June 1944, Section V, pp. 63-64), the Jan grid (TM 44-222, Section VI, pp. 65-66), and the Thrust Line Method (TM 44-222, Section VII, p. 67). These are special purpose systems and their continued use will not be affected by the adaption of a standard referencing system. (a) Advantages: The system is suitable for rapid computations of range and azimuth; no difficulties arise from the reversal of sign at the 0° and 180° meridians and at the Equator; a reference is brief and not complicated with decimals, hyphens and parentheses. (b) Disadvantages: It does not fill the needs of the Air Force and Navy; it is not easily adaptable to world wide use due to lack of order and homogenity; it does not provide for spheroid junctions; while it permits slight abbreviation in local areas, no provision is made for similar abbreviation for large scale activities; it does not allow for referencing in polar areas; the number of grid and datum junctions was excessive resulting in frequent difficulty in rapid computation of range and distance when origin and destination were in different grid areas. (4) Air Defense Grid (TM 44-225, Section X, pp.72-79) (a) Advantages: The Air Defense Grid referencing partially satisfies large scale use of the Air Force. (b) Disadvantages: The system does not satisfy the requirements of the Army and Navy; the system does not lend itself to the use of the pilot in fighter support; while it is fairly satisfactory in reporting areas in world wide activities it is not satisfactory for reporting spot positions; while it provides for abbreviation, in certain areas if the first letter of the reference is dropped, the nearest similar reference is near enough to create ambiguity; it is not suitable for rapid computation of range and azimuth; it does not provide for polar areas; it is ambiguous at datum junctions. 3. PROPOSED SYSTEM a. General The proposed system is based on the Universal Transeverse Mercator Grid between 80° N and 80° s; in the polar areas it is based on polar Stereographic grids. (1) In conjunction with these grids, the reference system meets all the requirements for a referencing system as outlined in paragraph 1, above. (a) It provides for the individual and collective needs of the Army, Navy and Air Force. The basic principles followed by any of the armed forces in giving a reference are alike; a reference cited by any one branch will be readily recognized by all and will permit easy conversion when required. (b) It provides a positive and unambiguous identification for any point on the globe especially at spheroid and datum junctions. (c) Since the referencing in all cases follows the basic and simple system of reading "right-up", a reference is easily understood. A reference is brief and is capable of being abbreviated either for local or large scale activities, thus satisfying any and all needs. (d) It is well suited for rapid computation of range and azimuth. (3) (e) It is suitable for polar areas. Azimuth will agree with that now in use by polar aviators; this avoids the difficulties of meridian convergence which are a necessary feature of computations in latitude and longitude. (f) There is no reversal of sign at any meridian or any other junction of zones. (2) The system has the following additional merits: (a) The coordinates always increase to the east and to the north, except in the polar regions where the direction of positive coordinates is umambiguously indicated. (b) The system conforms to the spherical surface of the earth. The grid line can be considered as a system of coordinates whose position on the earth's surface is as exactly fixed as meridians and parallels. (c) As the grid is conformal, it can easily be applied to a map constructed on any of the conventional projections, unless they are so extended as to have unusually large distortions. b. First division - 8° NS X 6° EW rectangles (1) Between 80° N and 80° S the world is divided into rectangles 8° NS X 6° EW (See Exhibit E-H). The columns (6° wide )are identified by the Universal Transverse Mercator(UTM) Zone numbers -- that is,starting at the 180° meridian the columns are numbered from 1 to 60 consecutively proceeding easterly. The rows (8° NS) are identified by letters; starting from 80° south and proceeding northerly the rows are lettered consecutively from C to X (I and O omitted). The designation (called the grid zone designation) of such an 8° NS X 6° EW rectangle is determined by reading (right-up) first the column designation (as 54) and second row designation (as U); as: 54U (2) The north polar area above the 80° parallel is divided into two parts by the 0° and 180° meridians; the half beginning west of 0° is identified as Y; the half beginning east of 0° is identified as Z __________ 3 See Appendix I. (See Exhibit I). Similarly,the south polar area below 80° is divided into two halves by the 0° and 180° meridians; these halves are identified by A and B respectively. c. Second division - 100,000 meter squares (1) Between 80° N and 80° S each 8° X 6° rectangle is divided into 100,000 meter squares based on the UTM grid for zone. Every column of squares is identified by a letter; likewise, every row of squares is identified by a letter. (See Exhibits A and B). On the equator, starting at the 180° meridian, and proceeding easterly for 18°,the 10,000 meter columns,including partial columns (caused by convergence), are lettered A to Z (I and O omitted) consecutively. The 100,000 meter rows are labelled from A to V (I and O omitted) reading from south to north, with the partial alphabet being repeated every 2,000,000 meters. Every odd numbered 6° wide UTM zone will have the alphabet of the 100,000 meter row letters beginning at the equator; the even numbered 6° wide UTM Zones will have the alphabet of the 100,000 meter row letters beginning at the 500,000 meter northing grid line north of the equator. This staggering will considerably lengthen the distance between duplicating letters and will permit necessary manipulation along spheroid junctions. Below the equator the 100,000 meter row letters will continue consecutively following the plan of the letters above in the same zone. The designation of a 100,000 meter grid square is determined by reading (right-up) first its column designation (as X) and second its row designation (as Q): as: XQ. (2) Under this system a 100,000 meter square designation will not be repeated in an aera 18° NS 18° EW. This will normally eliminate the necessity of preceding grid references within such an area by the grid zone designation (54U in b (1) above) even though report is being made from as many as two grid zones away. (3) In the polar areas the 100,000 meter columns at the right angles to the 90° - 90° meridians are lettered from J to Z in zone designation Y and A to R in zone designation Z (I and O omitted; also omitted are D, E, M, N, V and W to avoid confusion with 100,000 meter squares in adjoining UTM zones.Starting at the 80° line the 100,000 meter rows at right angles to the 0° - 180° meridians are labelled A to Z cosecutively (I and O omitted). The identification of a 100,000 meter square consists of two letters, reading right-up (See Exhibit I). d. Grid references for U.S. Army (1) A U.S. Army reference shall consist of a number and a letter (the grid zone designation) followed by two letters (identifying the 100,000 meter square in which the point of reference lies), followed by a group of numbers expressing to the required accuracy the E and N coordinates of the referred point within the 100,000 meter square; examples: (a) 54UXQ (locating a point within 100,000 meters) (b) 54UXQ55 (locating a point within 10,000 meters) (c) 54UXQ5354 (locating a point within 1,000 meters) (d) 54UXQ539544 (locating a point within 100 meters) (2) Normally, a general reference is seldom located to an accuracy of more than the closest 100 meters. To provide for the needs of surveying and to anticipate any contingency, the following references are provided: (a) 54UXQ53925443 (locating a point within 10 meters) (b) 54UXQ5392354432 (locating a point within 1 meter) (c) 54UXQ539234544321 (locating a point within 0.1 meters) (3) Normally,all elements of a grid reference shall not be used. Those to be omitted will depend upon the size of the area of activities. Thus: (a) If activities are confined to an area not exceeding 18° EW X 18° NS,the grid zone designation (54U) usually will be omitted. In such an area, a reference to the closest hundred meters usually will read: XQ539544 (b) If activities are confined to an area not exceeding 100,000 meters NS X 10,000 meters EW,in addition to omitting the grid zone designation, the 100,000 meter square identification (XQ) will be omitted; the point will be referenced only by numbers. Thus, in such an area, a reference to the closest hundred meters will read: 539544 (c) Numerical reference: The numerical part of a reference taken from a 1,000 meter grid, will be a six digit number; for example: 539544. The "53" represents the 10,000 and 1,000 digits of the easting grid line to the west of the referenced point, the "9" represents the estimated tenths from the easting grid line to the point, the "54" represents the 10,000 and 1,000 digits of the northing grid line south of the referenced point, and the "4" represents the estimated tenths from the norhthing grid line to the point. (See Exhibit C). To maintain a relationship between similar grid references from different scale maps, the numerical part of a reference taken from a 10,000 meter grid will be a four digit number; for example: 5354. The "5" represents the 10,000 digit of the easting grid line to the west of the referenced point, the "3" represents the estimated tenths from the easting grid line to the point, the second "5" represents the 10,000 digit of the northing grid line south of the referenced point, and the "4" represents the estimated tenths from the northing grid line to the point. (See Exhibit D). e. Tad Grid Reference (1) A TAD reference shall consist of two letters (identifying the 100,000 meter square containing the point of reference (see paragraph 3 c, above), followed by four numerals (the 10,000 and 1,000 digits of the northing grid line south of the point and the 10,000 and 1,000 digits of the easting grid line west of the point, (the identification of the 1,000 meter grid square containing the point), followed by a letter (identifying the 200 meter grid square containing the point). (See Exhibit F). Example: XQ5354J (2) The first two letters (XQ) normally shall be omitted; they will not be used unless the reference is being reported more than 100,000 meters away. Thus, the usual TAD reference will be written simply as: 5354J (3) The p1an for lettering the 200 meter squares follows: A B C D E F G H I J K L M N O P Q R S T U V W X Y f. Air Defense references (1) A reference shall consist of the grid zone designation (as 54U), followed, if necessary, by two letters (identifying the 100,000 meter square containing the point), followed, if necessary, by a group of numbers expressing to the required accuracy the E and N coordinates of the referred point within the 100,000 meter square; (See Exhibit G). Examples: (a) 54U (locating a point within a 8° NS X 6° EW) (b) 54UXQ (locating a point within 100,000 meters) (c) 54UXQ55 (locating a point within 10,000 meters) (c) 54UXQ5354 (locating a point within 1,000 meters) (2) If reports are being confined to an area not exceeding 18° NS X 18° EW, the grid zone designation may be omitted and the reference read as: (a) XQ (locating a point within the 100,000 meters) (b) XQ55 (locating a point within 10,000 meters) (c) XQ5354 (locating a point within 1,000 meters) 4. CONCLUSION It is felt that the system outlined above is a homogeneous solution of the problem and will satisfactory fill the needs of the Navy, the Air Force and Army. The needs of the various grid users are provided for and a standardization is effected. APPENDIX 1 STUDY AND DISCUSSION OF MILITARY GRIDS by Army Map Service and Military Intelligence Division, Office, Chief of Engineers, U.S. Army 1. Purpose of Study The purpose of the following study is to determine the characteristics required in a military grid and to select a system most nearly answering these requirements. Marked disadvantages are inherent in most grid systems now used. These disadvantages are complicated by the existence of many incompatible systems. 2. Existing Conditions 2.01. The polyconic military grid is prescribed by Section VII, AR 300-15, for use on all military maps of the United States. This system is laid out in zones 9 degrees wide in longitude with 1 degree of overlap between zones. It is so inaccurate at long ranges in certain directions that it cannot be used satisfactorily for the control of the fire of coast artillery weapons or heavy field artillery. 2.02. Because of this inaccuracy, the coast artillery harbor defense grid for area in the neighbourhood of the harbor defences in the continental United States is also authorized in paragraph 28, Change No.4, AR 300-15. This harbor defense grid system is a Lambert conic conformal designed particularly to serve the guns of the harbor defense concerned. It is not only not connected to the military grid system in the same area but is incompatible therewith. 2.03. Many other grid systems are in use not only in the Unites States but also in the rest of the world. Twenty states of the Unites States have adopted the state plane coordinate systems measured in feet and especially designed to serve the particular state in question. Each such system is hardly extensible beyond the borders of the state without the introduction of mater- ial inaccuracies. The enclosed map shows the overall picture of the grid systems used in allied military operations during the recent campaigns. (Incl. 1) 2.04. It is obvious that the presence of so many systems complicates map preparation and impose material confusing handicaps on actual combat operations. The presence of more than one grid system covering one area presents no particular problem in peace time or on manoeuvres involving but one arm. When the fog of war confuses men's minds, the presence of several coordinate systems in one area for use of different arms in fraught with potent opportunity for disasters resulting from uncoordinations attributed to mistakes in using the military grid. Involved in this matter are branch pride and branch stubbornness, each branch feeling justified in having a special grid system designed to the particular capabilities and needs of that branch. An example of this occurred in the United Kingdom where the British coast artillery, Navy and Air Force covered the coastal area with three incompatible, incommensurable grid systems. Intolerable confusion which resulted from the use of these grids during the numerous German air raids in the Battle of Britain makes it highly probable that these conflicting systems would have led to at least a few local disasters had there been an invasion of Great Britain. 3. Basic Requirements 3.01. Primary Purpose of a Grid: The primary purpose served by the military grid on a map is to provide quick solutions to problems of distance and azimuth for the firing of weapons. It provides a quick simple means for referring to spot locations and for designating targets. It is an essential tool in coordination of military operations. 3.02. The coordination of the efforts of the many arms used on land, sea, and air, is a problem so complex as to make mandatory a single simple solution for problems of target designation and determination of range and azimuth. This requirement is believed to be so important in war that the use of a single system of limited but adequate accuracy is held to be better than the simultaneous use of two incompatible but otherwise more accurate systems. 3.03. The characteristics of the using arms and weapons which affect the design of the system to be adopted involve relatively little research. As a general rule, it has been assumed that permanently emplaced batteries will be more accurate in their fire than batteries temporarily emplaced in the fields. Therefore, the following table appears to provide sufficient criteria to determine the desirable accuracies of the grid system adopted. Probable Errors of Different Caliber Permanently Emplaced Guns at Ranges Shown ------------------------------------------------------------------------ Minimum Probable Probable Errors in Yards Relative Errors -------------------------------------------------------------- Range in 6" Gun 8" Gun 16" Gun Yards Range Defl. Range Defl. Range Defl. Range Deflection 10,000 22 2 68 3 18 3 1:555 1:5,000 15,000 35 4 70 5 28 4 1:535 1:3,750 20,000 52 6 73 8 40 6 1:500 1:3,333 25,000 68 8 77 13 52 7 1:480 1:3,571 30,000 83 19 63 9 1:476 1:3,333 35,000 73 10 1:479 1:3,500 40,000 80 10 1:500 1:4,000 45,000 *77 *7 *1:584 *1:6,428 ------------------------------------------------------------------------ * These values are appear unusual 4. Desirable Characteristics 4.01. Primarily a grid system should be accurate enough for all weapons and all military uses other than for very long distance missiles, should be quickly applicable to any previously ungridded native map, should yield readily to simple computing methods and should provide simple numerical designators for location of targets. 4.02. Plane System. The system of coordinates desired is one with which all computations for the most accurate artillery firing can be simply yet accurately performed and especially one in which the integrity of angles is preserved. A mathematically exact graticule, such as that presented by the meridians and parallels, requires the use of geodetic functions to solve the spherical triangles involved, and entails a long, time-consuming complicated computation. Moreover, due to the convergence of the meridians, the arc of the latitude increases. Complicated geodetic formulas would be necessary in the computation of any distance except one along a meridian. Complex fire control instruments would be needed, manned by personnel highly trained in a branch of advanced mathematics. Neither the personnel, the instruments, nor the time are normally available. As a consequence, the system adopted should be one in which plane trigonometry can be employed in the solution of triangles. In such a plane system for general application to large areas, the simplest and quickest computations can be secured through use of a grid network of equally spaced parallel and mutually perpendicular lines. 4.03. Grid Accuracy. A high degree of accuracy is, of course, desirable. However, grid accuracies which are greatly in excess of the accuracies for the most precise weapon using the grid appear to be neither necessary nor practicable. By reference to paragraph 3.03 above, it will be noted that the probable errors of artillery weapons are much greater in range than are their probable errors in deflection. The minimum probable error of permanently emplaced guns rarely is less than 1/555 in range and 1/5,000 in deflection. Consequently, a suitable military grid should be one designed to conform to these minimum probable errors. 4.04. Adaptability to Various Projections. The grid system selected should be adaptable for use on native maps without complicated recomputation or redrafting of that map. There are many map projections used in the making of large scale maps throughout the world. It is desirable to be able to overprint the adopted grid system on any or all of these projections without the introduction of errors in range and azimuth beyond that probable in good artillery practice. 4.05. Unit of Measure. Three general systems of linear measure are commonly encountered on maps and in grids: the metric system, the so-called English system, the nautical system. Mixtures of these systems unfortunately are prevalent. This matter is further complicated by the fact that three differing elements are involved - map quantities, grid quantities, and the quantities employed by the using arms and weapons. a. Map quantities include azimuths, horizontal. distances, contour intervals, and underwater depths. To the map user, the unit of measure in which horizontal distances on a map are expressed is not particularly important, as the conversion from map distances to ground distances is frequently done graphically against either an appropriately graduated bar scale on the map or range scale. However, the unit of linear measure used in the basic survey of the map may complicate the computation and compilation trig lists for fire control. This latter operation is already quite complex due to the differing origins of longitude, datum planes, spheroids and schemes of projection, and other variations encountered in the native surveys of the world. Thus, the conversion from one unit of linear measure to another incommensurable. unit adds an operation subject to mistakes and affecting final accuracies. b. Contour intervals and spot elevations should, but may not, be in the same unit of measure as the horizontal distances, in order to provide for the ready calculation of true slant ranges, defilade, mask, profile, etc. c. Underwater depths are generally expressed either in meters or in fathoms, although shoal water depths may be also expressed in feet. It is highly desirable that these units of measure be the same as the horizontal unit in order to be readily useful in the computation fo underwater profiles and beach gradients. d. The military grid, while essentially concerned with angles and horizontal distances, must be precisely related to the computed geographic positions. The necessary correlation between the vertical unit of measure and the horizontal unit if measure on the grid as indicated in b above, is essential for the quick solution of problems involving defliade.,mask and true gun target distance. e. The using arms and weapons are not entirely coordinated in the units of measure employed in the laying of the piece. The Coast Artillery measures azimuths in degrees and hundredths of a degree from grid south as the origin. The Field Artillery measures angles in mils, with field orientation of base circles. The Coast Artillery measures its range in yards ,while the Field Artillery may measure it in yards or meters. Due to the tangent relationship of the mil, Field Artillery can readily transpose from angular measure to linear distance in either meters or yards. Each artillery weapon is served and laid by employing a multiplicity of tabular information, plotting tools, and gunner's instruments. All these things must be related to the unit of measure selected for map and grid quantities. At the present moment, due to the recent tremendous concentration of field artillery weapons in the European campaigns and to the use of the metric system throughout in that area, our Field Artillery is well equipped and trained in the use of the metric system. The Seacoast Artillery of the United States, including the Panama Canal and Oahu, are not so equipped or trained. They use the yard- hundredths of a degree system, except in the coast defenses of Sen Diego where coast Defense grid graduated in feet rather than in yards. f. Existing Conditions. The majority of the large scale maps of the world are made on the metric system.Exceptions to this rule are the United States, Canada, Australia, United Kingdom, Union of South Africa, India, Melanesia and Middle East. The following table shows teh unit of measure of native maps and military grids employed in operational areas of the recent campaigns. MAP UNITS GRID UNITS ------------------------------------------- ------------------- AREA HORIZONTAL UNIT VERTICAL DEPTH UNIT GRID GRID TYPE (Map Bar Scale) UNIT (Map (Bathymetric UNIT Contour) Contour) ----------------------------------------------------------------------------- 1. France Meter Meter Meter Meter Lambert 2. Germany Meter Meter Meter Meter Trans. Merc. 3. Italy Meter Meter Meter ----- ----- 4. Tunisia Meter Meter Meter ----- ----- 5. Libya Meter Meter Meter Meter Trans. Merc. 6. Egypt Meter Meter Fathon Meter Trans. Merc. 7. Okinawa Meter,Cho Meter Meter Meter Unknown 8. Burma Miles Foot Fathom Yard Lambert 9. China Li,meter Meter Fathom Yard Lambert 10. Russia Meter Meter Foot Meter Trans. Merc. 11. Hawaii Mile Foot Fathom Yard Polyconic 12. Philipines Mile Foot Fathom Yard Polyconic 13. Poland Meter Meter Meter Meter Stereographic 14. Holland Meter Meter Meter Meter Stereographic 15. Belgium Meter Meter Meter Meter Bonne 16. Japan Meter,Cho Meter Meter Meter Trans. Merc. 4.06. Width of Zone. An inherent fault of any system of plane coordinates applied to the surface of a spheroid is the fact that inaccuracies increase as the zone is extended east and west or in other cases, as the belt is extended north and south. It is also desirable, although not entirely necessary, to keep at a minimum the deviation of grid north from true north. This deviation likewise increases materially as the distance from the central meridian increases. These inaccuracies can be kept within reasonable limits by the adoption of narrow grid zones. It has been stated only semi-facetiously that there are three military engineering axioms: a. It always rains in war. b. It is always too cloudy to get aerial mapping photographs. c. Battles are always fought on grid junctions. This last axiom is spoken from the depths of bitter experience, rendering it obvious that a grid zone should include as much area as possible so as to obviate too frequent junctures between grid zones on the battlefield.However,this desirable criterion cannot be widely applied without including intolerable inaccuracies of the grid. Elimination of the undesirable features consequent upon fighting a battle on a grid juncture can be partially accomplished by providing for overlap between grid zones, the 9 degree width of the military grid system presently prescribed for use in the United States introduces appreciable inaccuracies near the edges. A reduction in width to 6 degrees betters this situation materially. The computation of ranges and azimuths where the gun position is located in one grid zone and target in another can be provided for by a half degree overlap between grid zones, enabling the coordinates of the gun zone to extended a half a degree into the grid zone in which the target is located. 5. Comparison of Grids 5.01. Polyconic Grid. For military Purposes, a grid may be regarded as a set of perfect squares ruled on a plane map, scale 1:1, and then transferred to the earth's surface. Evidently after being transferred to the earth's surface the squares will no longer be perfect; and distortions they will have received in being put on the surface of the earth will reflect the distortions of the projection used for the map. a. The polyconic projections is defined as one which the central meridian and all parallels are mapped to scale and with true curvature. All other lines are stretched, the amount increasing as the square of the distance from the central meridian, and being greatest for north-south lines. Angular errors also appear, increasing with distance from the central meridian. Of course it is possible to commute these errors, at least roughly, and to allow for them, and this is regularly done by engineer survey troops. But the corrections are generally considered beyond what is to be expected of artillery units in the field, and for that reason all mention of them is omitted in artillery technical manuals, even when survey procedures are discussed. It is proper, therefore, to compare the errors of the projection as shown in the following table, directly with the errors of the guns (Section 3.03). Errors of U.S.Military Grid at 4°30' from Central Meridian, and 30° Latitude ------------------------------------------------------------------------------------------------- | | | True | True Azimuth 0° | True Azimuth 45° | Azimuth 90° True |----------------------------|-----------------------------|---------------------------- Range | Range Rela- | Defl. Rela- | Range Rela- | Defl. Rela- | Range Rela- | Defl. Rela- (yds) | Error tive | Error tive | Error Defl. | Error tive | Error tive | Error tive | (yds) Error | (yds) Error | (yds) Error | (yds) Error | (yds) Error | (yds) Error ---------|--------------|-------------|--------------|--------------|--------------|------------- 10,000 | 23 1:435 | 0 0 | 12 1:836 | 12 1:836 | 0 0 | 0 0 30,000 | 70 1:428 | 4 1:7500 | 35 1:859 | 35 1:859 | 0 0 | 0 0 40,000 | 70 1:428 | 4 1:5000 | 47 1:850 | 47 1:850 | 0 0 | 0 0 It is evident that at 40,000 yards, and an azimuth of 45°, the error of the grid in deflection is almost five times the probable error of a 16-inch gun, Errors of the above amount are characteristic of the so-called non conformal projections, i.e. those in which the shapes, as well as the scale of small areas is distorted. Such non-conformal grids were widely used prior to World War I; but most of them have been abandoned in recent years, chiefly, no doubt, because of the breakdown of the old French Bonne grid during the War. In addition to its lack of conformality, the polyconic projection possesses the disadvantages that it has not been studied thoroughly from a mathematical standpoint. Hence the small corrections needed for precise surveys are not known; the transformation from other grids to the polyconic is not known; not even the transformation from one polyconic belt to another has been studied. b. So far as grid junctions are concerned,the polyconic is theoretically excellent; it can be extended indefinitely both north and south, so that the world can be divided up into meridional strips. In practice, the present World Polyconic has two latitudinal junctions, one near 24°, due to failure to put the origin of the old U. S. grid sufficiently far south; the other is near 49°, and is due to inaccuracy in the old tables which amounts to 1.1 meters. c. The polyconic grid is not well suited for foreign maps due to its lack of conformality. By the older laborious hand methods of grid plotting, this introduced no difficulties other than laborious calculations; but the use of the coordinatograph, for rapid plotting of grids and projections, requires a conformal grid. 5.02. Cassini-Soldner Grid. This is a non-conformal grid,very similar to the polyconic, and open to the same objections. It differs only in that the grid east-west lines, rather than the parallels are represented to true scale and with true curvature. 5.03. The Bonne Grid. Both meridians and parallels are represented to true scale on the Bonne projection; the error shows up on lines which run NE to SW, or NW to SE, It is just as bad as in the case of the other non-conformal projections; and this projection has been generally abandoned. 5.04. The Stereographic Grid. The stereographic grid may be briefly defined as a conformal grid (that is, one having zero angular distortions for small distances, and very small angular distortions for any distance) in which the scale error is zero on a standard circle. The fact that this grid is conformal insures that within about 200 miles of the center-point, the error in deflection will be less than the error of the most accurate guns. The range error is considerably larger than the deflection error, but is considerably less than the range error of permanently emplaced artillery. Unfortunately, this grid cannot be extended more than 300 miles from its center point and grid zones are circular in shape. It is quite suitable for small roughly circular countries such as Poland, Holland, or Romania, which use it; but on a world-wide basis it would lead to great multiplicity of grid junctions, and points where three or more grids meet could not be avoided. 5.05. Lambert Grid. Like the Stereographic, the Lambert is a conformal projection. It may not defined as a conformal projection in which the scale errors are zero along two parallels. It is well suited to the mapping of moderately large areas, and has been extensively used by the British and French, especially in recent years. The numerical values of the errors are similar to those for the Transverse Mercator given in the next paragraph. The errors are very small in deflection, as is necessary for an artillery grid. It is readily adaptable to gridding maps on other projections. In general, a slight change of scale only would be required. On the other hand, the rapidly increasing grid declination makes it impracticable to extend the grid more than about 15° from the central meridian (except along the Equator, where grid declination is always zero). For this reason, the British and French were forced to introduce numerous zones, and to permit junctions of three grids at the same point. These numerous grid zones necessary, both north-south and east-west, make the Lambert undesirable for extensive world coverage. 5.06. Transverse Mercator Grid. The Transverse Mercator grid may be defined as a conformal grid in which the central meridian is represented by straight line at the true scale. It is well suited to large areas, and is being used by the Germans, Russians, British, and Japanese. The errors at a given point vary little in all azimuths end average values for different ranges are given in the following table for 30° north latitude and for 3 1/2° from the central meridian. ------------------------------------------------------------------- | | Transverse | Transverse | | True | Mercator Grid | Mercator Grid | | Range | Range Relative | Deflection Relative | | (yds) | Error Error | Error (yds) Error | | | (yds) | | |--------|-----------------------------|--------------------------| | 10,000 | 10 1:1000 | 0 0 | | 30,000 | 30 1:1000 | 3 1:10000 | | 40,000 | 40 1:1000 | 5.8 1:6900 | |--------|-----------------------------|--------------------------| Obviously,t he grid is well suited to artillery purposes since the inevitable errors are thrown into range rather than deflection. The grid can be extended indefinitely in latitude like the polyconic. Hence it is never necessary to have a grid junction involving more than two grids (except, of course, near the Poles). Transformation of coordinates from one belt to another can be done by a formula already worked out. The formula is always the same, and is very simple in character. The grid declination will remain moderate throughout the belt. The grid can be readily adapted to use on other projections. Much theoretical work has already been done on this subject by a large group of mathematicians, including especially Professor W. K. Hristow. Extensive computations, especially for the Balkan Countries, were done by the German High Command (O. K. H.)during World War II which could, in an emergency, be promptly utilized if the proposed projection is adopted. In addition, much geodetic data of foreign areas on file at Army Map Service are on this system. The projection is well suited for converting data on various spheroids to a common basis. Traverse and lower orders of triangulation may be computed and adjusted directly on the grid due to its conformality. This feature, which is a large saving in field and office, is not practicable where a non-conformal projection such as the present Polyconic is used. 5.07. Tabular Comparison of Grids. -------------------------------------------------------------------------------------- GRID SYSTEM APPLICABILITY GRID MAXIMUM MAXIMUM TO FOREIGN MAPS** JUNCTIONS RELATIVE RELATIVE RANGE ERRORS* DEFLECTION (45,000 yds) ERRORS* (45,000 yds) -------------------------------------------------------------------------------------- Polyconic Very Poor Few & simple 1/1228 1/2454 Cassini-Soldner Very Poor Few & simple 1/1228 1/2454 Bonne Very poor Many & complex 1/2454 1/615 Stereographic Good Many & complex 1/2454 1/15,360 Lambert Good Many & complex 1/2416 1/7,663 Transverse Mercator Excellent; much work already done Few & simple 1/2416 1/7,663 --------------------------------------------------------------------------------------- * Range and deflection errors are maximum values within 160 miles from the center of the projection, whether the center is a line, as in the Transverse Mercator, Lambert, Cassini-Soldner, and Polyconic, or a point as with the other two. The figures are based on GSGS "Survey Computation". 160 miles is the approximate distance (at 40° of latitude) from the center of the proposed Transverse Mercator Zones to the junctions, about 3° of longitude. The actual maximum errors of the present world Polyconic grid are considerably larger, since the grid zones are 9° in width. 6. Conclusions as to System to be Adopted 6.01. The Lambert Orthomorphic projection is conformal but is not suitable as it requires grid zone junctures both north and south and east and west. The ployconic grid system now prescribed for use as military grid on all maps of U. S. is inaccurate in both azimuth and distance. The greater inaccuracy is in azimuth and is more than the probable error in deflection of permanently emplaced guns. The transverse mercator grid is conformal and is ----------------- **A grid system is considered applicable to a foreign map if it can be put on most maps without changing map or grid except is scale. immediately applicable without plottable error, to the majority of the map projections commonly encountered on the native maps of the world. The transverse mercator grid reduces inaccurecies to a point where they are compatible with the accuracies required by all modern artillery weapons. This grid is sufficiently accurate to eliminate the necessity for a special Coast Artillery grid in the vicinity of coast defense locations. APPENDIX 2 1. FIRE CONTROL REFERENCING Existing regulations of the Department of the Army (See FM 6-40, Part Four, Chapter 2) designate the following method for reading a gird reference. a. Designatiuon of sheet, parenthesis, X coordinate, decimal, location to nearest yard, a dash, Y coordinate, decimal, location to nearest yard, parenthesis. Example: Annapolis (804.729-1286.684) b. When the map is definitely understood, its designation may be omitted. Example: (804.729-1286.684) c. If the location to the nearest 10 or nearest 100 yards only is desired, or if the measurements can not be made with greater accuracy, the digits indicating units or tens may be omitted. Examples: (1) (804.72.1286.68) to nearest 10 yards. (2) (804.7.1286.7) to nearest 100 yards. d. For expediency it is permissible to include only two digits to the left of decimal point (10,000 and 1,000 digits), omitting any preceding digits. Examples: (1) (04.729-86.684) (2) (04.72-86.68) (3) (04.7-86.6) e. If the point is fixed within an area 10,000 yards square, only one digit need be given before the decimal point of each coordinate. Examples: (1) (4.729-6.684) (2)(4.72-6.68) (3)(4.7-6.7) f. If a large number of points are being designated by the abbreviated coordinates shown in example (3), the decimals and dashes may be omitted and the reference given as (4767). 2. PACIFIC WORLD WAR II PRACTICE During the war, the Pacific and Southwest Pacific Commands found it feasible to use a system for reading general grid references similar to that used with British Girds. Apparently, a broad interpretation of existing regulations was made to find authority for the change. The name of the map was not mentioned (authority: see 1 b above) digits to the left of the 10,000 and 1,000 unit digits were omitted (authority see 1 d above) decimals and dashes were omitted (authority see 1 f above). a. A reference on a map employing a 1,000 unit interval was determined by reading the 10,000 and 1,000 digits of the easting line to left of point, estimated tenths(100 units) eastward to point, the 10,000 and 1,000 digits of the northing line south of the point, estimated tenths (100 units), northward to the point. This was written as a 6 digit continuous number. Example: 143286 b. A similar procedure was follows in reading a reference on a map using a 10,000 unit interval, except that the digits for the gird lines were for the 100,000 and 10,000 units (the last four digits being omitted) and the estimated tenths represented 1,000 units. Thus, a reference for the same point cited in (1) above, was as: 214128 c. There were two major faults with the pacific system: danger of confusion between a reference taken from a map bearing a 1,000 unit interval and from one of a 10,000 unit interval, inasmuch as both were six digit numbers; and lack of connection between references for a common point taken from a 1,000 unit gird and from a 10,000 unit gird, inasmuch as in reading a reference from a 1,000 unit gird the principal digits were the 10,000 and 1,000 ones and for a reference from a 10,000 unit grid the principle digits were the 100,000 and 10,000 ones. Thus, references for a common point might read: 047866 (from a 1,000 unit gird) and 804286 (from a 10,000 unit gird). 3. BRITISH GRID REFERENCING References for british grids are read according to the following methods: a. Maps bearing a 10,000 unit interval (1:100,000 to 1:500,000): letter of 500,000 unit source (written as a small capital letter), letter of 100,000 unit square (written as a large capital letter), 10,000 digit of easting line to the left of the point, estimated tenths (1,000 units) eastward to point, 10,000 digit of northing line south of the point, estimated tenths (1,000 units) northward to the point. Example: cA1428 This locates point to nearest 1,000 units. b. Maps bearing a 1,000 unit interval (1:5,000 to 1:100,000 inclusive): Letter of 100,000 unit square, 10,000 and 1,000 digits of easting line to left of point, estimated tenths (100 units) eastward to point, 10,000 and 1,000 digits for northing line south of the point, estimated tenths (100 units) northward to the point. Example:A143286 The locates point to nearest 100 units.

### MGRS vs USNG Differences — Differences Between MGRS and USNG MGRS and USNG 100,000-meter Square Identifications are Different when Used with the NAD 27 Datum Both the MGRS and USNG systems default to the WGS84 datum.
https://maptools.com/tutorials/mgrs_usng_diffs

Differences Between MGRS and USNG MGRS and USNG 100,000-meter Square Identifications are Different when Used with the NAD 27 Datum Both the MGRS and USNG systems default to the WGS84 datum. They differ when used with the NAD 27 Datum. This is particularly important to users within the Continental Unites States, where many topographic maps produced by the United States Geologic Survey are referenced to the NAD 27 Datum. The MGRS System shifts the second letter of the 100,000-meter square identification by ten letters (excluding I and O). The USNG system does not make this letter shift, but does require that the datum be specified. The example coordinate we have been using would look like this when referenced to the NAD 27 Datum: MGRS: 10S GU 0706832 4344683 USNG: 10S GJ 0706832 4344683 (NAD 27) The letter shift also occurs in MGRS when working with other datum that use the Bessel 1841 and Clarke 1880 ellipsoids, which includes much of Africa, Japan, Korea, and Indonesia. When you are working with old maps and MGRS coordinates, be aware that occasional unusual letter adjustments have been used in the past. Since most land navigation users drop the GZD and Grid Letters, the shift usually has little impact, unless you need to enter MGRS coordinates into your GPS for far away locations. USNG is only defined for use "over all areas of the United States including outlying territories and possessions" This allows the definition of USNG to avoid a number of complications. It does not include the UPS coordinate system for polar regions, nor does it need the zone boundary exceptions defined for Norway. USNG allows the use of only the three datums (NAD83, WGS84 or NAD27) commonly used in the United States. The default USNG datum is NAD 83. WGS 84 is considered an acceptable alternative to NAD 83 When using NAD27 you must explicitly specify it. For example, 10S GJ 068 446 (NAD27). MGRS coordinates may be used with any datum, and there is no formal way to specify the datum. (It is still very important to specify the datum. It’s just not formalized how to write it.) 100,000m truncation not specified in USNG MGRS allows you to reference an entire 100,000m square area, e.g. 10S EH, whereas USNG suggests at least two digits and thus the largest area that can be described is a 10,000m square, e.g. 10S GJ 0 4. The USNG does not specifically prohibit 100,000m truncation, but instead omits it from the standard document, whereas the MGRS standard specifically includes it.

### Plotting a Bearing on Your Map — Using a protractor to plot a bearing onto your map Plotting a bearing onto your map Bearings, Azimuths, Headings, and Course Some reasons to plot bearings onto your map Location by Resectioning or "Where am I?
https://maptools.com/tutorials/plotting/plotting-a-bearing

Using a protractor to plot a bearing onto your map Plotting a bearing onto your map Bearings, Azimuths, Headings, and Course Some reasons to plot bearings onto your map Location by Resectioning or "Where am I? Location by Intersection or "Where is the ______ that I can see in the distance? Plotting straight line course segments for route finding The example problem used in this tutorial Understand your north references Understanding forward and back bearings Techniques for plotting a bearing: Plotting a bearing using a protractor Plotting a bearing using a baseplate compass Plotting a bearing using a baseplate compass adjusted for declination Plotting a bearing using a straight edged lensatic compass Plotting a bearing using a round lensatic compass Plotting a second and third bearing to confirm your position Using bearings to locate a distant target Some exercises to download and try Plotting Bearings Exericse Map This file is just the map. The description of the problem and the answers are in the lecture slides. (see link below) Here is the map with the answers plotted Plotting Bearings Answers Locating the Smoke Exercise This is a complete exercise for locating an unknown location using intersecting bearings. This is the answer map. There is also a set of lecture slides for this exercise. Lecture Slides for this topic are available from the Resources for Navigation Instructors page. A bearing from a known location X to an unknown location ?, measured relative to a north reference line. There are many different scenarios that lead to plotting a bearing on a map. Most of them involve a known location, an unknown location, and a north reference. The bearing is the angle formed by two lines that start from the point the measurement is made. One line extends from this point towards North. The other line extends from this point to some distant target. The point at which the measurement is made may be either the known or unknown location. A single known point and a bearing, is not enough information to determine the location of the unknown point. It will define a line along which the unknown point is located. To locate the unknown point we need at least on more piece of information. That could be another bearing from a different known point. Or it could be a distance from the original known point. Or it could be a map feature that we know the unknown point is located along, like a road, trail, or stream, or a contour line of a given elevation. Bearings, Azimuths, Headings, and Course The disciplines of navigation, surveying, and astronomy all have slightly definitions of these terms. Here are some simple definitions that will serve you well for land navigation. Bearing - A horizontal arc or angle measured from a north reference line, in a clockwise direction, to a point of interest some distance away from the point of measurement. In land navigation the terms bearing and azimuth are interchangeable. Azimuth - See bearing. In land navigation the terms bearing and azimuth are interchangeable. Heading - Your forward facing direction of travel. In air and sea navigation heading refers to the forward facing direction of your aircraft or vessel. Course - Your desired direction of travel. Your course will be different from your heading when you are "off-course." In air and sea navigation, your course or "course over ground" is the direction of travel of your aircraft or vessel. Here your course may differ from your heading due to influences of wind and current. This is rarely a problem when navigating by foot. Some reasons to plot bearings onto your map Location by Resectioning or "Where am I?" A single bearing to a peak resulting in two possible locations along the trail. A bearing to a second peak, identifies the location along the trail. If you can see at least two and preferably three locations that you can identify on your map, you can take compass bearings to these locations, and plot them on your map. Your location will be where the bearing lines cross. It is often difficult to identify more than one known location that you can see. In this case you can often combine other information about your location to use with a single bearing line. If you are on a trail that you can identify on the map, but you are not sure of your exact location along the trail, You can take a bearing to a known peak, plot that bearing, and know that you are where the bearing line crosses the trail. Note, it is possible the bearing intersects the trail in more than one place. In this case, you will need additional information to determine which crossing is your present location. You can use any of the following linear features to intersect with one or more bearings. Provided you can identify the feature on the map and you are sure your position in somewhere along the feature you have identified. Roads and trails Rivers, streams and shorelines Ridge lines and spurs Fence or power lines A contour line at your current elevation A special case of location by resectioning is useful when you are using a GPSr with a map that does not have a coordinate grid. Rather than using your compass to sight a bearing to a known location, you enter the coordinates of a known location into your GPSr. Using the GOTO Waypoint feature, your GPS will calculate both the bearing and distance from your current location, to the known location on the map. Look for a new tutorial on this method in the coming weeks. Location by Intersection or "Where is the ______ that I can see in the distance?" Locating a plume of smoke using bearings from two or more known locations. You see something off in the distance, say a plume of smoke. You know where you are and you take a compass bearing from your location to the smoke. Now you can plot a line on your map and know that the source of the smoke is somewhere along that line. Moving to a new, known location and taking a bearing, will result in another line. The source of the smoke should be at the intersection of the two bearing lines. Moving to yet another known location, taking a bearing and plotting it, will provide you some protection from any error you may have made. If the three bearings all cross in close proximity, you can be confident of your results. With only two bearings, errors will not be apparent. Plotting straight line course segments for route finding One technique for route finding is to combine a series of straight line "course legs" to reach the desired destination. The techniques discussed in this tutorial can be used to plot these legs onto a map. The example problem used in this tutorial A map of a small lake, somewhere in the north woods. We are staying at a cabin on a small lake somewhere in the north woods. We decide to take a hike around the shore of the lake. At some point on our hike we stop and look across the lake. We can see our cabin. We can also see what looks like a cave entrance along the lake shore. We would like to know where this cave is on our map. Our cabin is a known location that we can identify on the map. We also know that all three of these locations are along the shoreline of the lake. We do not know our current location, nor do we know the location of the cave. There will be two parts to solving this problem. First we will take a bearing to our cabin, and plot it on our map. Our location will be where the bearing to our cabin crosses the lake shore. Ideally we could find some other know location and plot a second bearing to give us more confidence in our location. Now we are ready to locate the cave. We take a bearing from our location to the cave entrance, and plot it on the map. The cave is located where the bearing crosses the lake shore across the lake from our location. To improve the confidence in out result, we should move to a new position along the shore line and repeat the entire procedure to give us a second bearing line to the cave. We will return to this example as we continue through this tutorial. Understand your north references So far we have not been very specific about what North means. But there are three different Norths commonly used in navigation, and it is very likely that the North our compass uses and the North we see on our map are different. If you don't already understand north references and converting between them, you should take a detour to our North Reference Tutorial. For our example at the lake in the north woods, we will assume that our compass bearings are taken relative to Magnetic North and our map plotting is done using Grid North. In this part of the north woods, Magnetic North is 5° east of Grid North. Converting from Magnetic North to Grid North We will likely need to make any adjustments to our north references as we move bearing between our compass and our map. Let's take a look at a declination diagram that shows both Grid and Magnetic North along with the bearing line to the cabin. The angle between the line to Magnetic North and the line to your cabin, is what we measured with our compass. The angle between the line to Grid North and the line to your cabin, is what we will be plotting on our map. Note the angle from your cabin to Grid North is 5° bigger than the angle from the cabin to Magnetic North. Thus, to convert from a Magnetic North bearing to a Grid North bearing we need to add on 5°. Learning to draw diagram like this one will allow you to figure out all of your north reference conversions, wherever you are in the world. Make sure you use current declination information for your location. Understanding forward and back bearings Taking a forward bearing. The first compass bearing we need to take at the lake is from our unknown location to our cabin on the far shore. The bearing we end up with represents the angle between a line from Magnetic North to our location, and a line from our location to the cabin. This bearing is a "forward bearing." But when we go to plot this bearing on our map, we can't plot the angle from our current location since that is what we are trying to find. Instead we plot a bearing from the cabin, as if someone there took a bearing "looking BACK towards our location." This would be called a "back bearing" and will be 180° different from our "forward bearing." If you took the bearing from the known location, you will be plotting a forward bearing, starting at the known location. If you took the bearing from the unknown location, you will be plotting a back bearing, starting at the known location. For more information on forward and back bearings, see our tutorial on forward and back bearings. This tutorial will show you how to plot a bearing using different techniques and equipment. I usually start my students off using a protractor. A protractor has no moving parts and is conceptually simpler to use. Techniques for plotting a bearing... Plotting a bearing using a protractor Plotting a bearing using a baseplate compass Plotting a bearing using a baseplate compass adjusted for declination Plotting a bearing using a straight edged lensatic compass Plotting a bearing using a round lensatic compass Continue this tutorial on plotting a bearing with these links: Plotting a second and third bearing to confirm your position Using bearings to locate a distant target

### Plotting a Bearing with a Compass — Plotting a bearing on a map using a baseplate compass Plotting a bearing on a map using a baseplate compass Sighting a bearing to a distant target.
https://maptools.com/tutorials/plotting/compass

Plotting a bearing on a map using a baseplate compass Plotting a bearing on a map using a baseplate compass Sighting a bearing to a distant target. Sighting the bearing To determine our location we are going to combine two pieces of information on our map. We know that we are somewhere along the shoreline of the lake. Using a compass we can sight a bearing to our cabin across the lake. When we plot the bearing on our map, our location will be where the line between our location and the cabin crosses the shoreline of the lake. Rough direction to the cabin. Determine a rough direction to the target Use a compass to get a general sense of direction for North, South, East, and West. Identify on of the eight compass points (N, NE, E, SE, S, SW, W, NW) that roughly describes the direction to our sighting target. In our example at the lake, our cabin is NE of our current location. Refer back to this "reality check" occasionally during plotting to make sure what you are doing makes sense. Sight the bearing to the target Using our compass we have sighted a bearing to our cabin of 60° from Magnetic North. The north reference is an integral part of any bearing. Make sure you include it when you say or write a bearing. We can abbreviate to either 60° Mag. or just 60°M A map of a small lake, somewhere in the north woods. Adjust the north reference to match the map We want to plot our bearing onto the map relative to Grid North. Looking at the declination diagram on the map, we see that in this part of the north woods, Magnetic North is 5° east of Grid North. We will add 5° to our bearing to convert it from a Magnetic bearing to a True bearing. If you don't already understand north references and converting between them, you should take a detour to our North Reference Tutorial. Our bearing was taken from an unknown location, towards a known location. When we plot it on the map, we will start plotting at the known location, and extend the bearing line back towards the unknown location. This is known as a back bearing. For more information on forward and back bearings, see our tutorial on forward and back bearings. Step-by-step procedure for plotting with a baseplate compass Step 1: Adjust the compass to the desired bearing. Step 2: Align the compass capsule with the north reference lines. NOTE: The magnetic needle is not used, and may point in any direction. We do not need to orient the map with North. Step 3: Move an edge of the compass to the known point. Step 4: Draw the bearing line using the edge of the compass. Done: We have determined our location on the lake shore. Additional techniques for plotting a bearing... Plotting a bearing using a protractor Plotting a bearing using a baseplate compass adjusted for declination Plotting a bearing using a straight edged lensatic compass Plotting a bearing using a round lensatic compass Continue this tutorial on plotting a bearing with these links: Plotting a second and third bearing to confirm your position Using bearings to locate a distant target

### Plotting a Bearing with a Protractor — Plotting a bearing on a map using a protractor Plotting a bearing on a map using a protractor Sighting a bearing to a distant target.
https://maptools.com/tutorials/plotting/protractor

Plotting a bearing on a map using a protractor Plotting a bearing on a map using a protractor Sighting a bearing to a distant target. Sighting the bearing To determine our location we are going to combine two pieces of information on our map. We know that we are somewhere along the shoreline of the lake. Using a compass we can sight a bearing to our cabin across the lake. When we plot the bearing on our map, our location will be where the line between our location and the cabin crosses the shoreline of the lake. Rough direction to the cabin. Determine a rough direction to the target Use a compass to get a general sense of direction for North, South, East, and West. Identify on of the eight compass points (N, NE, E, SE, S, SW, W, NW) that roughly describes the direction to our sighting target. In our example at the lake, our cabin is NE of our current location. Refer back to this "reality check" occasionally during plotting to make sure what you are doing makes sense. Sight the bearing to the target Using our compass we have sighted a bearing to our cabin of 60° from Magnetic North. The north reference is an integral part of any bearing. Make sure you include it when you say or write a bearing. We can abbreviate to either 60° Mag. or just 60°M A map of a small lake, somewhere in the north woods. Adjust the north reference to match the map We want to plot our bearing onto the map relative to Grid North. Looking at the declination diagram on the map, we see that in this part of the north woods, Magnetic North is 5° east of Grid North. We will add 5° to our bearing to convert it from a Magnetic bearing to a True bearing. If you don't already understand north references and converting between them, you should take a detour to our North Reference Tutorial. Our bearing was taken from an unknown location, towards a known location. When we plot it on the map, we will start plotting at the known location, and extend the bearing line back towards the unknown location. This is known as a back bearing. For more information on forward and back bearings, see our tutorial on forward and back bearings. Familiarize yourself with your protractor Before you set you protractor down onto the map, take a good look at it and make sure you understand the markings. For navigation purposes, we use an angular measurement system where a circle is divided into 360 degrees. 0° (and 360°) are aligned with our north reference, 90° is to the East, 180° to the South, and 270° to the West. Is you protractor marked in degrees? Are the marks spaced at one, two, or five degrees? Is it a full or half circle protractor. Are the numbers increasing as you proceed in a clockwise direction? Many protractors used for drafting are numbered in both clockwise and counterclockwise directions. Make sure you use the correct set of numbers. Some protractors are numbered in four 90° quadrants, and are a probably not a good choice for navigation use. Find the center point for your protractor. You will place the center of the protractor on the known point where you are plotting your bearing. The center of your protractor will be at the intersection of a line drawn between 0° and 180° and a line between 90° and 270° Determine what lines to use to align your protractor with your north reference lines on your map. A protractor that is well suited for navigation will have numerous parallel lines aligned with 0° to 180° on the protractor. Step by step procedure for plotting with a protractor Step 1: Place the center point of your protractor on the known point. Step 2: Rotate the protractor so that it is aligned with the north reference lines on your map. Step 3: Mark the map along the edge of the protractor at the desired bearing. Step 5: Extend the bearing line towards the unknown point using a straight edge. Done: Now we know our location on the lake shore. Techniques for extending the bearing line One of simplest techniques is to place a small pencil mark on the correct bearing at the edge of the protractor. Now place a straight edge between the known point and the mark you made at the edge of the protractor. Draw a line between these two points, and extend it as far as you need to. This is what we demonstrated in the above example. Another technique is to use a piece of thread to show your bearing line. Many of our tools with protractors have a hole in the center. Place a piece of thread or a small string through the center hole and tie the ends together. (The string should be a bit longer that twice the distance you might want to extend a bearing.) Pull the string tight, line it up with the bearing on the edge of the protractor, and use the straight line created by the thread to follow the bearing away from the edge of the protractor. MapTools does not supply the string. Some field expedient string sources include, thread from a sewing kit, a thread from the core of a piece of para-cord, dental floss. Some folks like red thread, others prefer black, and some want a loop of thin elastic cord. If your string is too short to make a loop, tie the end to a small twig, a button, or something that is bigger than the hole in the tool. Additional techniques for plotting a bearing... Plotting a bearing using a baseplate compass Plotting a bearing using a baseplate compass adjusted for declination Plotting a bearing using a straight edged lensatic compass Plotting a bearing using a round lensatic compass Continue this tutorial on plotting a bearing with these links: Plotting a second and third bearing to confirm your position Using bearings to locate a distant target

### Plotting Bearings to Locate a Target — Using bearings to locate a distant target Using bearings to locate a distant target Now that we have determined our location on the map.
https://maptools.com/tutorials/plotting/bearings-to-locate-target

Using bearings to locate a distant target Using bearings to locate a distant target Now that we have determined our location on the map. We can proceed to locate the cave entrance we can see across the lake. Using our compass we sight a bearing to the cave and get a result of 96°M or 101°G. Note that this time we are sighting from a known point to an unknown point. Thus, we will plot a forward bearing, starting at the known point on the map. The cave entrance is located. But we do not yet have the extra information to alert us to any errors we may have made. We could increase out confidence by re-sighting and re-plotting the bearing to the cave. Or with more effort on our part, we could move to another location on the lake shore, take bearings to locate our new position on the map, and sight a second bearing to the cave. When you are attempting to locate an unknown point, it is best if you can take sightings from locations that are easily identified on your map.

### Plotting Lat/Lon Coordinates — Plotting and Measuring Latitude Because the lines of latitude are parallel and evenly spaced, a degree of latitude represents a constant distance on the ground.
https://maptools.com/tutorials/lat_lon/plotting

Plotting and Measuring Latitude Because the lines of latitude are parallel and evenly spaced, a degree of latitude represents a constant distance on the ground. This makes plotting latitude quite straight forward. Place the ruler so that it spans the lines of latitude the point to be measured or plotted falls between. Orient the ruler north to south. The zero minute end of the ruler should be on the southern line of latitude, when you're in the northern hemisphere. To measure the latitude of a point on the map, read the value from the ruler at the point, and add it to the latitude of the line at the zero end of the ruler. On the picture to the left, the ruler indicates the X is at the 4' mark, for a resulting latitude of 37° 34' N. To plot the location of given coordinates, make a small mark on the map to indicate the line of latitude the coordinates fall on. Plotting and Measuring Longitude Longitude represents an east-west position on the earth. Longitude increases as you move away from the prime meridian, or 0°, in Greenwich, England. Because the lines of longitude converge at the poles, a degree of longitude represents a varying distance on the ground, depending on the latitude. Place the ruler so that it spans the lines of longitude the point to be measured or plotted falls between. The ruler will need to be on a diagonal to fit. To measure the longitude of a point on the map, slide the ruler vertically, keeping the ends on the lines of longitude marked on the map, until the edge of the ruler touches the point to be measured. You may need to extend the lines of longitude above or below the map to properly position the ruler. On the picture to the left, the ruler indicates the X is at the 3.5' mark, for a resulting longitude of 122° 3.5' W. To plot a longitude coordinate, make a small tic on the map to indicate the line of longitude. The point of interest is located where the plotted lines of latitude and longitude cross. If plotting longitude seems tedious, check out our new Custom MapRulers, with a longitude scale adjusted to a particular latitude. We will custom make you a Map Ruler for any map scale you need. The rulers have a longitude scale speciffically designed for any latitude of your choice. The longitude scale will work well within a 1 to 2 degree band of latitude. No more need to use the ruler on a diagonal when you want to plot longitude. Watch the Video Tutorials on Plotting and Measuring Lat/Lon. | Previous | Index | Next |

### Plotting More Bearings to Confirm Location — Plotting additional bearings to confirm a location Plotting additional bearings to confirm a location So far we have determined our location using a single bearing to a known feature and the knowledge that we are on the shoreline of the lake.
https://maptools.com/tutorials/plotting/more-bearings-to-confirm-location

Plotting additional bearings to confirm a location Plotting additional bearings to confirm a location So far we have determined our location using a single bearing to a known feature and the knowledge that we are on the shoreline of the lake. These two pieces of information intersect in two possible places. But since we know which side of the lake we are on, and that the cabin is across the lake from our location, we know which intersection to use for our location. What we do not know is what impact any number of possible errors might have on our location. What could these errors be? Error in sighting the bearing to the cabin. Wrong cabin, or cabin is in the wrong place on the map. Water line has changed from what is shown on the map. Error in plotting the bearing onto the map. The solution is to use more than the minimum amount of information required. In our example we can take a bearing on a second known cabin. Doing that, our compass provides a result of 125°M or 130°G. These two bearings cross near, but not exactly on the shoreline. But we know that our feet are not wet. So there is either some error in the location of the shoreline on the map, or in the bearings we have plotted. Unless we had reason to suspect the shoreline on the map, we would likely assume a bit of sighting or plotting error and adjust out position to the mapped shoreline nearest the bearing intersection. Plotting a third bearing will likely confirm if the problem is error in out sighting and plotting, or the mapped position of the shoreline. We take a sighting to the location where a stream runs into the north end of the lake and get a result of 40°M or 45°G. With the third bearing plotted we see that our bearings do not intersect at a single point. This is common, and indicates that there is some error in our sighting and plotting. The smaller the triangle, the smaller the errors. The shoreline of the lake is within the small triangle formed by our bearings and is likely the best overall location to use as our current location. Now we can locate the cave on the opposite shoreline. In the last part of this tutorial we can use a bearing to locate a distant object. In our example this is a cave entrance we can see across the lake.

### Plotting with a Digital Protractor — Plotting a bearing on a map using a digital protractor Plotting a bearing on a map using a digital protractor Sighting a bearing to a distant target.
https://maptools.com/tutorials/plotting/digital-protractor

Plotting a bearing on a map using a digital protractor Plotting a bearing on a map using a digital protractor Sighting a bearing to a distant target. Sighting the bearing To determine our location we are going to combine two pieces of information on our map. We know that we are somewhere along the shoreline of the lake. Using a compass we can sight a bearing to our cabin across the lake. When we plot the bearing on our map, our location will be where the line between our location and the cabin crosses the shoreline of the lake. Rough direction to the cabin. Determine a rough direction to the target Use a compass to get a general sense of direction for North, South, East, and West. Identify on of the eight compass points (N, NE, E, SE, S, SW, W, NW) that roughly describes the direction to our sighting target. In our example at the lake, our cabin is NE of our current location. Refer back to this "reality check" occasionally during plotting to make sure what you are doing makes sense. Sight the bearing to the target Using our compass we have sighted a bearing to our cabin of 60° from Magnetic North. The north reference is an integral part of any bearing. Make sure you include it when you say or write a bearing. We can abbreviate to either 60° Mag. or just 60°M A map of a small lake, somewhere in the north woods. Adjust the north reference to match the map We want to plot our bearing onto the map relative to Grid North. Looking at the declination diagram on the map, we see that in this part of the north woods, Magnetic North is 5° east of Grid North. We will add 5° to our bearing to convert it from a Magnetic bearing to a True bearing. If you don't already understand north references and converting between them, you should take a detour to our North Reference Tutorial. Our bearing was taken from an unknown location, towards a known location. When we plot it on the map, we will start plotting at the known location, and extend the bearing line back towards the unknown location. This is known as a back bearing. For more information on forward and back bearings, see our tutorial on forward and back bearings. Step by step procedure for plotting with a digital protractor Additional techniques for plotting a bearing... Plotting a bearing using a protractor Plotting a bearing using a baseplate compass Plotting a bearing using a baseplate compass adjusted for declination Plotting a bearing using a straight edged lensatic compass Plotting a bearing using a round lensatic compass Continue this tutorial on plotting a bearing with these links: Plotting a second and third bearing to confirm your position Using bearings to locate a distant target

### Plotting with a Round Lensatic Compass — Plotting a bearing on a map using a round lensatic compass Plotting a bearing on a map using a round lensatic compass Sighting the bearing To determine our location we are going to combine two pieces of information on our map.
https://maptools.com/tutorials/round-lensatic

Plotting a bearing on a map using a round lensatic compass Plotting a bearing on a map using a round lensatic compass Sighting the bearing To determine our location we are going to combine two pieces of information on our map. We know that we are somewhere along the shoreline of the lake. Using a compass we can sight a bearing to our cabin across the lake. When we plot the bearing on our map, our location will be where the line between our location and the cabin crosses the shoreline of the lake. Rough direction to the cabin. Determine a rough direction to the target Use a compass to get a general sense of direction for North, South, East, and West. Identify on of the eight compass points (N, NE, E, SE, S, SW, W, NW) that roughly describes the direction to our sighting target. In our example at the lake, our cabin is NE of our current location. Refer back to this "reality check" occasionally during plotting to make sure what you are doing makes sense. Sight the bearing to the target Most lensatic compass have a compass card marked in 5° and 10 mil increments. 5° is not precise enough for anything but the crudest work, so it makes sense to make our sightings and do our plotting using mils. Using our compass we have sighted a bearing to our cabin of 1070 mils from Magnetic North. The north reference is an integral part of any bearing. Make sure you include it when you say or write a bearing. We can abbreviate to either 1070 mils Mag. or just 1070 mils M We will be plotting our bearing relative to Magnetic North, so there is no need to adjust for a different north reference. Our bearing was taken from an unknown location, towards a known location. When we plot it on the map, we will start plotting at the known location, and extend the bearing line back towards the unknown location. This is known as a back bearing. For more information on forward and back bearings, see our tutorial on forward and back bearings. Establish an accurate Magnetic North reference line We will be orienting our map with Magnetic North. To do this we need to establish an accurate Magnetic North reference line on the map. You may be tempted to use the MN line on the declination diagram, but be careful. The declination diagram may not be drawn with an accurate angle, or the angle may not represent the current declination. The smaller the angle to Magnetic North, the more likely the diagram will show a larger angle. The older the map, the more likely the declination shown in the diagram is no longer correct. Generally once you have drawn your own Magnetic North line, you will not need to do this again on this map sheet for many years. Using a protractor aligned with either True or Grid North (depending on what the magnetic declination you are given is referenced to), make a mark on the map at the desired value. Then use a straight edge to draw and label the Magnetic North Reference line. Step by step procedure for plotting with a round lensatic compass Orient the map with Magnetic North A round lensatic compass has no straight edge to align. Instead, you will use an imaginary line that runs down the center of the compass. Two parts of this line include the sighting wire, which you can align with things that are visible on the map, and the center of the rotating compass card. Some of these compasses have a notch at each end of the housing along this line. If your compass does not have these notches, you should add them. Use a straight edge aligned with the sighting wire and central pivot point. Mark the position of the notches to be with a pencil. Use a file to make a permanent notch at each end. Or make a permanent scratch mark, paint line, or permanent marker line on each end.You will use these notches to align your compass with a line on the map or to mark the location of a bearing line you are about to draw. Align your compass along your Magnetic North reference line. Now rotate the map and the compass as a unit, until the compass dial is aligned with north. Note that we are using the magnetic dial in the compass. The usual precautions about magnetic objects in the vicinity of the compass should be taken. Pay particular attention to the surface you are working on. Many wooden tables also have bolts, nails, screws, and other metal components. Don't even consider using the hood or tailgate of a vehicle. Orient you compass with the bearing, and draw the bearing line Next, without changing the orientation of you map, move your compass so that the point you are plotting to/from is under the sighting wire, and the compass dial reading matches your bearing. Make a mark with your pencil at the notch on the end furthest from the sighting wire. Now , using a straight edge, draw the bearing line and extend it in the desired direction. In our example will extend the line as a back bearing. We have established our location on the map The location we sighted the bearing to the cabin is where the back bearing intersects the lake shore. In order to detect any errors we may have made, it is recommended that you plot at least one additional bearing to a different known location. The need to carefully orient the map, and the precautions about metal in the vicinity of the compass makes this type of plotting more difficult than most other methods. Perhaps this is why most military personnel are trained to plot bearings using a protractor on a Coordinate Scale and Protractor tool. Additional techniques for plotting a bearing... Plotting a bearing using a protractor Plotting a bearing using a baseplate compass Plotting a bearing using a baseplate compass adjusted for declination Plotting a bearing using a straight edged lensatic compass Continue this tutorial on plotting a bearing with these links: Plotting a second and third bearing to confirm your position Using bearings to locate a distant target

### Plotting with a Straight Lensatic Compass — Plotting a bearing on a map using a straight edged lensatic compass Plotting a bearing on a map using a straight edged lensatic compass Sighting the bearing To determine our location we are going to combine two pieces of information on our map.
https://maptools.com/tutorials/plotting/straight-lensatic

Plotting a bearing on a map using a straight edged lensatic compass Plotting a bearing on a map using a straight edged lensatic compass Sighting the bearing To determine our location we are going to combine two pieces of information on our map. We know that we are somewhere along the shoreline of the lake. Using a compass we can sight a bearing to our cabin across the lake. When we plot the bearing on our map, our location will be where the line between our location and the cabin crosses the shoreline of the lake. Rough direction to the cabin. Determine a rough direction to the target Use a compass to get a general sense of direction for North, South, East, and West. Identify on of the eight compass points (N, NE, E, SE, S, SW, W, NW) that roughly describes the direction to our sighting target. In our example at the lake, our cabin is NE of our current location. Refer back to this "reality check" occasionally during plotting to make sure what you are doing makes sense. Sight the bearing to the target Most lensatic compass have a compass card marked in 5° and 10 mil increments. 5° is not precise enough for anything but the crudest work, so it makes sense to make our sightings and do our plotting using mils. Using our compass we have sighted a bearing to our cabin of 1070 mils from Magnetic North. The north reference is an integral part of any bearing. Make sure you include it when you say or write a bearing. We can abbreviate to either 1070 mils Mag. or just 1070 mils M We will be plotting our bearing relative to Magnetic North, so there is no need to adjust for a different north reference. Our bearing was taken from an unknown location, towards a known location. When we plot it on the map, we will start plotting at the known location, and extend the bearing line back towards the unknown location. This is known as a back bearing. For more information on forward and back bearings, see our tutorial on forward and back bearings. Establish an accurate Magnetic North reference line We will be orienting our map with Magnetic North. To do this we need to establish an accurate Magnetic North reference line on the map. You may be tempted to use the MN line on the declination diagram, but be careful. The declination diagram may not be drawn with an accurate angle, or the angle may not represent the current declination. The smaller the angle to Magnetic North, the more likely the diagram will show a larger angle. The older the map, the more likely the declination shown in the diagram is no longer correct. Generally once you have drawn your own Magnetic North line, you will not need to do this again on this map sheet for many years. Using a protractor aligned with either True or Grid North (depending on what the magnetic declination you are given is referenced to), make a mark on the map at the desired value. Then use a straight edge to draw and label the Magnetic North Reference line. Step by step procedure for plotting with a straight edged lensatic compass Orient the map with Magnetic North Place the straight edge of your compass along your Magnetic North reference line. Now rotate the map and the compass as a unit, until the compass dial is aligned with north. Note that we are using the magnetic dial in the compass. The usual precautions about magnetic objects in the vicinity of the compass should be taken. Pay particular attention to the surface you are working on. Many wooden tables also have bolts, nails, screws, and other metal components. Don't even consider using the hood or tailgate of a vehicle. Orient you compass with the bearing, and draw the bearing line Next, without changing the orientation of you map, move your compass so that its edge is touching the point you are plotting to/from and the compass dial reading matches your bearing. Now draw the bearing line using the edge of the compass, and extending it in the desired direction. In our example will will extend the line as a back bearing. We have established our location on the map The location we sighted the bearing to the cabin is where the back bearing intersects the lake shore. In order to detect any errors we may have made, it is recommended that you plot at least one additional bearing to a different known location. The need to carefully orient the map, and the precautions about metal in the vicinity of the compass makes this type of plotting more difficult than most other methods. Perhaps this is why most military personnel are trained to plot bearings using a protractor on a Coordinate Scale and Protractor tool. Additional techniques for plotting a bearing... Plotting a bearing using a protractor Plotting a bearing using a baseplate compass Plotting a bearing using a baseplate compass adjusted for declination Plotting a bearing using a round lensatic compass Continue this tutorial on plotting a bearing with these links: Plotting a second and third bearing to confirm your position Using bearings to locate a distant target

### Plotting with Declination Adjustment — Plotting a bearing on a map using a baseplate compass adjusted for declination Plotting a bearing on a map using a baseplate compass adjusted for declination Sighting a bearing to a distant target.
https://maptools.com/tutorials/plotting/compass-declination

Plotting a bearing on a map using a baseplate compass adjusted for declination Plotting a bearing on a map using a baseplate compass adjusted for declination Sighting a bearing to a distant target. Sighting the bearing To determine our location we are going to combine two pieces of information on our map. We know that we are somewhere along the shoreline of the lake. Using a compass we can sight a bearing to our cabin across the lake. When we plot the bearing on our map, our location will be where the line between our location and the cabin crosses the shoreline of the lake. Rough direction to the cabin. Determine a rough direction to the target Use a compass to get a general sense of direction for North, South, East, and West. Identify on of the eight compass points (N, NE, E, SE, S, SW, W, NW) that roughly describes the direction to our sighting target. In our example at the lake, our cabin is NE of our current location. Refer back to this "reality check" occasionally during plotting to make sure what you are doing makes sense. Check the declination adjustment on your compass Our intent is to adjust for the difference between Magnetic North and Grid North on our compass, so that we do not have to make any further adjustments or calculations out in the field. Whenever you move to an area where the declination is different, you will need to readjust your compass. It's a good idea to occasionally check that your compass is adjusted correctly. Gear driven declination adjustment These compasses are typically adjusted using a small screw head on the bottom of the baseplate. The screw head drives a small gear which in turn rotates the Orienting Arrow inside the capsule. A small red index line has been moved 5° in the direction labeled "E. Dec." In the view from the top we see the Orienting Arrow is no longer parallel to the Meridian Lines. Instead it points 5° East of North. On a compass where the Magnetic Needle Orienting Arrow can be moved independently of the rest of the compass capsule, an adjustment for 5° East will look like this: Friction fit declination adjustment The Meridian Lines on these compasses are typically printed on the Angular Measurement Ring. Since the entire capsule rotates, this is the only way to keep the Orienting Arrow independent of the Meridian Lines. It is somewhat more difficult to align this style of Meridian Lines, with the north reference lines on your map. On a compass where the compass capsule is moved relative to the angular measurement ring, an adjustment for 5° East will look like this: Sight the bearing to the target Using our compass we have sighted a bearing to our cabin of 65° from Grid North. The north reference is an integral part of any bearing. Make sure you include it when you say or write a bearing. We can abbreviate to either 65° Grid or just 65°G A map of a small lake, somewhere in the north woods. Adjust the north reference to match the map We want to plot our bearing onto the map relative to Grid North. Since we adjusted our compass to read directly relative to Grid North, no adjustment needs to made to our bearing If you don't already understand north references and converting between them, you should take a detour to our North Reference Tutorial. Our bearing was taken from an unknown location, towards a known location. When we plot it on the map, we will start plotting at the known location, and extend the bearing line back towards the unknown location. This is known as a back bearing. For more information on forward and back bearings, see our tutorial on forward and back bearings. Step by step procedure for plotting with a baseplate compass adjusted for declination Step 1: Adjust the compass to the desired bearing. Step 2: Align the compass capsule with the north reference lines. NOTE: The magnetic needle is not used, and may point in any direction. We do not need to orient the map with North. Step 3: Move an edge of the compass to the known point. Step 4: Draw the bearing line using the edge of the compass. Done: Once again we have determined our location on the lake shore. Additional techniques for plotting a bearing... Plotting a bearing using a protractor Plotting a bearing using a baseplate compass Plotting a bearing using a straight edged lensatic compass Plotting a bearing using a round lensatic compass Continue this tutorial on plotting a bearing with these links: Plotting a second and third bearing to confirm your position Using bearings to locate a distant target

### Privacy Policy — Our Policies Our basic policy is that we want our customers to have quality mapping tools that meet their needs.
https://maptools.com/policy

Our Policies Our basic policy is that we want our customers to have quality mapping tools that meet their needs. We do occasionally make mistakes and sometimes a product that doesn't meet our quality standards slips out. Please let us know if there is a problem, we want to get it right. Once your needs are met, we won't send you marketing emails to encourage you to buy more stuff. We expect that as a satisfied customer you'll return when you next have a need for our products. At MapTools.com, we are committed to protecting your privacy. We use the information we collect about you to process orders, provide customer support, determine our sales tax obligations, and nothing else. Please read on for more details about our privacy policy. Privacy What information do we collect? How do we use it? Information You Provide Shopping and Ordering When you place an order or use our shopping cart, we need to know your name, e-mail address, mailing address, phone number, and the items you have added to your shopping cart. This allows us to process and fulfill your order and to notify you of your order's status. Payment Information Your credit card information is transmitted directly from your web browser to our payment processor. We never see your card number, and it is not stored on our server. The payment processor returns a token to us that can only be used for a transaction between MapTools and your card account. With that token we can authorize and complete a single charge, or refund all or part of that charge. While quite secure, it can be a bit limiting as well. If you call or email us with a request to add an item to your order or ship by a faster more costly method, we will need to get your card information again for the additional charge. Communications If you contact us by email, telephone, or fax, we may receive additional information about you such as your name, email address, phone number, the contents of the message and/or attachments you may send us, and any other information you may choose to provide. Information We Collect When You Use Our Services Web Server Log Files As is true of most websites, we gather certain information automatically and store it in log files. In addition, when you use our Services, we may collect certain information automatically from your device. This information may include internet protocol (IP) addresses, browser type, internet service provider (ISP), referring/exit pages, operating system, date/time stamp, clickstream data, landing page, and referring URL. Cookies We use cookies to identify your web browsing session. This allows us to keep track of the items in your shopping cart, the details of any custom tools you are constructing, and your login status if you are a registered user. If your web browser refuses to store our cookie, you will likely be unable to use our shopping cart to order products. Visiting MapTools' website with your browser settings adjusted to accept cookies tells us that you want to use MapTools' products and services, and that you consent to our use of cookies to provide them to you as described in this notice. Unlike many other websites, we do not use cookies for advertising, or to attempt to track other websites that you visit. We do not add any third party cookies for advertising, tracking, or analytical purposes. What do we do with the Information we collect? Primarily we use the information to process your order, and keep you informed about it. On rare occasions we have used the information to contact customers that ordered a product that we later discovered had a problem they should be aware of. Occasionally we have sent an email about a new product to customers that have made inquiries in the past about the availability of a product like the new one. Your Choices Should you receive a promotional email from us in the future, we will provide a link to opt out of further promotional emails. Currently, we are not sending promotional emails. Many browsers have the option to disable, selectively enable, or remove cookies. Please note that, if you choose not to accept cookies, some features of our Services, most notably the shopping cart, may no longer work for you. Disclosure We provide you name and shipping address to our shipping carriers when we determine the cost of shipping your order, and again when we purchase and print the shipping label. Currently, we are using the services of EasyPost.com for this. We do not sell, trade, or rent your personal information to others. The exception to that policy would be when we reasonably believe it is necessary to comply with a subpoena, court order, law, or regulation. We may disclose your personal information to the extent required to fulfill our legal obligation. Security All personal information is collected via HTTPS secure communication and is kept in a secure database. We employ a variety of security technologies and measures designed to protect information from unauthorized access, use, or disclosure. The measures we use are designed to provide a level of security appropriate to the risk of processing your personal information. We work hard to keep up with current security practices. There are only two of us here at MapTools, so we think it is unlikely that there will be a theft of data by an insider. However, please bear in mind that the Internet cannot be guaranteed to be 100% secure. Data Retention We retain personal information we collect from you where we have an ongoing legitimate business need to do so (for example, to provide you with a service you have requested or to comply with applicable legal, tax, or accounting requirements). Access You may request access to information associated with your orders by emailing me at john@maptools.com. You may also request removal of the information associated with your orders by emailing me at john@maptools.com. Business transfer If MapTools is involved in a business acquisition, merger, sale, reorganization, or bankruptcy then your personal information may be transferred as part of the restructuring. I promise that either the acquiring institution will respect your personal information and file data in accordance with this privacy policy, or that you will be given the opportunity to opt-out of the transfer. Changes to this Privacy Policy This Privacy Policy may be modified from time to time. Changes to this Privacy Policy will be posted on our website. If we materially change the ways in which we use or share personal information previously collected from you through our Services, we will notify you through our Services, by email, or other communication. Returns and Refunds We want you to have quality tools that are right for the task at hand. If that's not what happened, we want to know. We'll gladly exchange tools, so you get the right one. We gladly issue a refund, if you just want to return your purchase. Often we will not even want you to return the product. They just don't cost enough to get all worked up over returning a small plastic card, and we'll just send you a replacement. For larger orders and more expensive items, we'll usually want the product back. If it's our error that led to the problem we'll cover the return shipping. If the error or change comes from your end, we would ask that you cover the return shipping. We try to keep our policies short and simple. There is room for abuse, but thus far it's not been a problem. We don't want to ever have to write pages of legalese which you have to "agree to" before ordering. Please help us keep it that way by working with us to solve any problems you have. We're just people too. And we're working hard doing what we love to do.

### Rebelle Rally Map Rulers
https://maptools.com/rally

### Recommended Books — Book Recommendations Books for learning wilderness navigation Wilderness Navigation: Finding Your Way Using Map, Compass, Altimeter & Gps (Mountaineers Outdoor Basics) This is the book I use as a textbook in my college level Wilderness Navigation class.
https://maptools.com/books

Book Recommendations Books for learning wilderness navigation Wilderness Navigation: Finding Your Way Using Map, Compass, Altimeter & Gps (Mountaineers Outdoor Basics) This is the book I use as a textbook in my college level Wilderness Navigation class. It's good, inexpensive, and readily available. Navigation: Finding Your Way on Mountain and Moorland This is one of the best books on wilderness navigation I have ever seen. A bit more expensive, and harder to find, it is worth it. Ultimate Navigation Manual by Brotherton, Lyle (2011) A very through and modern book on wilderness navigation. Full of clever tips and techniques. Books on the history of Mapping and Surveying Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time The Riddle of the Compass: The Invention that Changed the World The Great Arc: The Dramatic Tale of How India Was Mapped and Everest Was Named Measuring America: How the United States Was Shaped By the Greatest Land Sale in History

### Resources — Useful resources on the MapTools website If you use maps, GPS receivers, and a compass for navigating you will find our site to be full of useful resources.
https://maptools.com/resources

Useful resources on the MapTools website If you use maps, GPS receivers, and a compass for navigating you will find our site to be full of useful resources. We have tools for plotting UTM, MGRS, and USNG coordinates, and rulers for plotting latitude longitude coordinates. We also have a number of other useful mapping and navigation tools. If you are looking for a tool to use with a specific map scale, here is a listing of our tools sorted by scale. If you are new to navigation using GPS coordinates, check out our tutorials. If you would like us to send you a catalog in the mail, you can order one at no charge (for U.S. addresses). Or you can download a copy of our catalog as a pdf file. If you teach navigation skills, check out our Resources for Navigation Instructors where I share many of the presentations and handouts that I use. If you a more of a do-it-yourself type, we have some coordinate plotting tools available as downloadable pdf files. If you still have questions try our Frequently Asked Questions, Useful Links to Other Sites, or Contact Us directly. If you would like to purchase our tool locally, we do have a listing of dealers. If you would like to resell our products to your customers, here is information on our wholesale purchasing policies. If you are purchasing for a government entity or a school, college, or university here is information for government purchasers.

### Shipping Information — Shipping Policies Shipping Charges It is not our goal to make money on shipping.
https://maptools.com/shipping

Shipping Policies Shipping Charges It is not our goal to make money on shipping. Our goal is to charge you as close to our actual shipping cost as the shopping cart is capable of calculating. Our minimum shipping charge is $2.00. We ship via the United States Postal Service Most order ship in a flat first class envelope. We have found this to offer a fast, affordable, and reliable delivery. Please be sure to provide a shipping address that is usable by the post office. First class mail is not trackable. If you need tracking, please select one of the Priority Mail services. If USPS delivery just won't do. We can also ship via UPS and FedEx. Neither service is integrated into the online shopping cart yet. Let us know which carrier and delivery speed you prefer. You can explore the options and costs on the carrier's website. Orders ship from the 94062 zip code. When we ship orders Typically, we ship orders every weekday the Post Office is open. Most days orders go to the post office late afternoon Pacific Time. Rush Orders The shopping cart will offer Priority Mail Express as the fastest shipping option. Priority Mail Express offers 1 to 2-day delivery times. You can check the USPS website for shipping from our zip code, 94062, to your zip code for better estimate on delivery times. The earlier in the day we get your order, the more likely it is that we can get it to the post office in time for overnight delivery. Often we can ship a rush order the same day via FedEx, it's not an option on the shopping cart, so you'll need to call us. Our local FedEx pickup occurs at about 3:30pm Pacific Time. If you need same day rush shipping, please call or email to confirm that it will be possible. International Shipping We ship lots of orders to international destinations. Our shopping cart can provide you with shipping options and costs. We ship using the United States Postal Service. Tracking is available through their website up to the point the shipment departs the United States. The shipment is usually delivered by the receiving country's postal service, tracking is sometimes available. Delivery times are somewhat unpredictable, but most orders do eventually arrive. In some countries, customs fees and duties will be charged. You are responsible for paying these costs. Sorry but we can not declare your order to be a gift, nor can we misstate the value or content of the order. Orders in Retail Packaging Orders that ship to our resellers in Point-of-Sale retail packaging take a few extra day to process.

### Straight Line Courses — Straight Line Courses The shortest distance between two points is a straight line.
https://maptools.com/straight_line_courses

Straight Line Courses The shortest distance between two points is a straight line. But, a straight line is almost never the best or fastest path to hike from one place to another. Many of our navigation tools and techniques push us towards using a straight line for a course. Knowing when to let man made features, the terrain and/or the vegetation direct your course and when to stick close to a straight line, or a sequence of shorter straight lines is a key skill to master as you learn to navigate. Most of the tools used by land navigators were initially developed for navigating the open oceans and the skies. Both environments where it makes sense to plan a journey as a sequence of straight lines. On the water the forces that work to push you off course are wind and currents. It is not uncommon for the direction your vessel is heading to be different from the direction in which it is actually moving. Traveling cross-country on the ground has a very different set of forces pushing you. For example, you may be influenced by the slope of the land pushing you downslope or into a drainage. You are often making course changes to avoid obstacles both small and large. When the terrain is easy to follow, there are easily recognized features at the end of your course legs, and any exiting hazards are visible, you probably don’t need to use either your compass or GPSr. Use your map and follow a combination of man made features and the terrain as you progress along your route. When the terrain is difficult to follow, but the hazards are few and are visible, it’s not so important that you stay on course. You just need to locate the ends of the course legs. Use your GPSr with waypoints at the end of each course leg. You can navigate with separate activation of the GOTO feature for each waypoint or combine them into a route. You will be free to avoid obstacles and pick the easier paths, and your GPSr will always be able to tell you the direction to the end point and how far away it is. You may decide to only use your GPSr occasionally rather than continuously. You may also choose to use your compass to keep you headed in the general direction of the end point. You should realize that as you drift away from the planned course line the compass bearing to the end point will change. You can use the GPSr to get an updated bearing from your current location. When the terrain is difficult to follow, and there are hazards to be avoided, plan on being able to closely follow your course legs. You may luck out and conditions will allow for a looser more visual method of navigation. But you should be prepared to navigate in poor visibility, darkness, or past invisible hazards. You will likely want to use you GPSr continuously. You may also wish to supplement the GPSr with your compass taking both forward and back bearings when visibility permits. One of the most common techniques for navigating with a map and compass involves planning a series of short course legs on your map connected by straight lines. Using your compass or a protractor, you measure the direction of each of these course legs. After taking into account the different north references between your map and your compass, you proceed to use your compass to find the direction to hike for that course leg. To assure that you remain on the course line, you will identify landmarks both ahead and behind you on the course. As long as your forward bearings and your back bearings match your course bearing, you are on course. When they differ, it’s time to get back on course by moving in a perpendicular direction to your course. Off course. Your forward and back bearings don't match your course bearing. A well planned course leg will have an easily located feature to mark is end point. If you are relying on the distance traveled to locate the end point, perhaps by counting paces, avoiding obstacles becomes even more complicated. Now you need to count only the forward progress on the course line not your cross track movements around obstacles. When you are off course, your compass no longer points you towards your destination. Instead, it points to a course that is parallel to your desired course. This is one of the major differences between using a compass and using a GPSr. A GPSr set to navigate to the end of a course leg, will constantly recompute the course from your current location to the end of the leg. The course your GPSr is describing is still a straight line. But here is the big difference, being off course is usually not a big problem, since the GPSr is still directing you to the end of the leg. This gives you a lot of freedom to maneuver around obstacles and move with the terrain, without having to worry about getting back on the straight line course. Most of the time your journey will be faster and easier when you have the freedom to work with the terrain. However, whenever there are unseen hazards to either side of your course line, staying on the straight line course is important. Cliffs and swamps are hazards that are usually visible, and can be avoided by sight in the daylight with good visibility conditions. Hazards like snow covered crevices and minefields are not apparent even with the best visibility. Typically, the end of a course leg is entered into your GPSr using a coordinate measured on your map. When you can preplan your course, it is considerably faster to create a series of waypoints using computer map software and uploading them to your GPSr. It is also possible to create a new waypoint by using a stored waypoint offset by a bearing and distance. Most GPSr have a “project waypoint” feature where you can enter the bearing and distance. Short course legs are desirable when you plan to use you compass for navigation. The longer the leg the greater the error will be from a small bearing error and the greater potential for a distance measurement error. But if you are planning to use your GPSr, short course legs can be problematic. Your GPSr reports its position it is somewhere in a blob of position error. I usually think of this as a 10m circle. If you are using your current location, as shown by your GPSr, and then projecting it to create a new waypoint, your course leg will have a 10m error circle at each end. For legs that are shorter than 100m, you will likely have better accuracy using a compass. In any event, you should not plan course legs that take you closer than 20m to a hazard when you plan to navigate with your GPSr. Image caption Image caption When you want to use your GPSr to travel a straight line course leg where it is important that you stay on course, a single waypoint with the GOTO feature is not sufficient. You will need to create a route with at least two waypoints. Once you have started your GPSr navigating the route, you will want to find the screen with the “compass display” and activate its course or CDI (course direction indicator) mode. In course mode the arrow that points to the next waypoint has an offset line to indicate how far and in what direction you are off course. Make sure to check the settings for the course pointer. You will want small off course distances to be visible on the pointer when you are traveling by foot. In an airplane or boat being a few hundred meters off course is usually of no significance, and you would only want larger course errors to show on the course pointer. Check that the map datum on your map matched the setting in your GPSr Check the north reference setting on your GPSr and compass. Review the current declination and any conversions you will need to make as you move between the map, your compass, and your GPSr. Check the distance setting for the course pointer or CDI on your GPSr. If you have many waypoints in your course plan, consider using your computer to create and upload them to your GPSr.

### Useful Links — WebSite Links Thanks much for visiting us!
https://maptools.com/links

WebSite Links Thanks much for visiting us! Here are a few of the sites around the web that we recommend Sam Wormley's Guide to GPS and Mapping Sites Coordinate Systems Overview Global Positioning System Overview USGS -- The Universal Transverse Mercator (UTM) Grid fact sheet Google Earth: the black helicopters have landed David Rumsey Historical Map Collection Geocaching Coordinate Conversion at Jeeep.com Google Earth Software Geographic Names Information System TopoMap Software Vendors DeLorme (Now part of the Garmin family

### Using UTM Coordinates — A Quick Guide to Using UTM Coordinates Standing at the center of the marker shown on the map below, a GPS unit set to display position in UTM/UPS format, would report a location of: Let's look at where the various parts of the UTM position come from on the map.
https://maptools.com/tutorials/utm

A Quick Guide to Using UTM Coordinates Standing at the center of the marker shown on the map below, a GPS unit set to display position in UTM/UPS format, would report a location of: Let's look at where the various parts of the UTM position come from on the map. The map has grid lines spaced every kilometer or 1000 meters. The grid is labeled with UTM coordinate values. The vertical grid lines determine East-West position and the horizontal grid lines determine North-South position. Look along the bottom edge of the map at the labels for the vertical grid lines. The label, , reads "seven hundred and six thousand meters East." The label, , is an abbreviation for, The two grid lines are 1000 meters apart. The horizontal grid lines are labeled in a similar manner. The 10S is the Grid Zone Designation you are in. The Grid Zone is necessary to make the coordinates unique over the entire globe. The top set of numbers, 706832, represent a measurement of East-West position, within the Grid Zone, in meters. It's called an Easting. Using a map with a 1000m grid, the first digits are come from the label for the grid line to the west of the position. The last 3 digits are the distance in meters measured from the western grid line. The bottom set of numbers, 4344683, represent a measurement of North-South position, within the Grid Zone, in meters. It's called a Northing. Using a map with a 1000m grid, the first digits are come from the label for the grid line to the south of the position. The last 3 digits are the distance in meters measured from the southern grid line. Using various tools to plot and measure UTM positions on a map Click on the tab for the tool style you want to know more about. Grid Style Tool Slot Style Tool Corner Style Tool Mini Corner Style Tool Map Ruler Style Tool Using a grid style tool to plot/measure a UTM position with 100m precision Using a slot style tool to plot/measure a UTM position with 10m precision Using a corner ruler roamer style tool to plot/measure a UTM position with 10m precision Using a mini corner style tool to plot/measure a UTM position with 10m precision Using a map ruler to plot/measure a UTM position with 10m precision See these tools in motion The pictures above freeze a tool in its final position. If you'd rather watch it get there, the interactive UTM tutorial animates the whole sequence on a real topographic map — the grid lines sweeping in to bound the square, the tool sliding into place and squaring up to the grid, the digits being read off the scales, and the point finally marked. Step through it at your own pace, in either direction: Plot a UTM coordinate onto the map Read the UTM coordinate of a feature The precision of the Easting and Northing measurements A UTM coordinate's Easting and Northing are both distance measurements made in meters. But this leaves us with a dilemma when we have not measured with one meter precision. What to do with the unknown digits. Let's look at the Easting of a point that is 146m east of the western grid line. T hat would, in our example above, give it an Easting of 706146m E. But on a large scale map, no tool will be able to measure to the nearest meter. At best you'll get 10 meters, and if you're eyeballing it you'll be good to get 100m accuracy. But we still have to write all the digits down to the meter. The convention is to fill in the unknown/unmeasured digits with zeros, and to avoid any rounding up. So our easting becomes 706140m E or 706100m E. The trouble is we don't know if the location we are measuring was located with great accuracy at 706100m E, or if we just did a 100m rough measurement and the location could have an easting between 706100m E and 706199m E. One possible solution is to write the Easting an Northing in kilometers, using as many digits after the decimal point as we have measurement accuracy. For improved clarity, write the measurement units with the Easting and Northing In the world of map coordinates, there are a lot of different coordinate formats. If you just run a bunch of digits together with no spacing or units, you run the risk of having someone else misunderstand what coordinate format you are using. In the case of UTM, I suggest writing "m E" for "meters East" after the Easting, and "m N" for "meters North" after the Northing. When communicating a coordinate by voice, say the words "meters East" after the Easting and "meters North" after the Northing. There are several documented cases where a string of digits was passed, usually by voice, to someone else who misinterpreted the coordinate format. In one case this led to the rescue helicopter being sent 30 miles away from the actual incident. Learn more about... The interactive UTM tutorial — plot and read coordinates step by step Map Datums and why they are so important Locating MGRS grid information on USGS topographic maps Grid Zone Details Metric Distance Measurements UTM Practice Exercise Some of the history behind the military adoption of UTM and MGRS More than you probably want to know... National Geospatial Intelligence Agency Standardization DocumentUniversal Grids and Grid Reference Systems (101 page pdf) National Geospatial Intelligence Agency Standardization DocumentThe Universal Grids and the Transverse Mercator and Polar Stereographic Map Projections (86 page pdf)

### Using UTM on USGS Maps — UTM, MGRS, and USNG Coordinates on USGS Topographic Maps All USGS topographic maps printed in the last 30 years or so include either UTM grid lines, in black or UTM grid tick marks, in blue, on the margin of the map.
https://maptools.com/tutorials/utm_on_usgs_maps

UTM, MGRS, and USNG Coordinates on USGS Topographic Maps All USGS topographic maps printed in the last 30 years or so include either UTM grid lines, in black or UTM grid tick marks, in blue, on the margin of the map. The UTM Grid lines are also used with MRGS and USNG coordinates. Printed UTM Grid Lines The map has grid lines spaced every kilometer or 1000 meters. The grid is labeled with UTM coordinate values. The vertical grid lines determine East-West position and the horizontal grid lines determine North-South position. Look along the bottom edge of the map at the labels for the vertical grid lines. The label, 249000mE, reads "two hundred forty-nine thousand meters East." The label, 248, is an abbreviation for, 248000mE. The two grid lines are 1000 meters apart. The horizontal grid lines are labeled in a similar manner. UTM Tick Marks, No Grid Lines Since many USGS 1:24,000 scale topographic maps do not have grid lines printed on them, you will need to draw them in by hand. Start by finding a flat surface to work on. Use a straightedge that is long enough to draw a line across your map. Two to three feet long is a good length. Line the straightedge up between two corresponding UTM tick marks along the neat line (the edge) of the map. Remember that UTM grid lines are not exactly North-South or East-West anywhere but in the center of a zone. This means that the grid lines will not be parallel to the neat lines. Using a mechanical pencil or a fine pointed pen draw a line between the two tic marks. If you are using a pen, select one that has waterproof ink. In addition, you will want to use a straightedge that has the edges lifted off of the paper. This will help keep from leaving an ink smudge when you move the straightedge. High quality straightedges will often have a thin piece of cork stuck to the bottom. This helps keep the rule from slipping, and keeps the edge off of the paper. A piece of masking tape centered on the bottom of your straightedge will work also. Occasionally wipe of the edge of the straightedge to avoid any ink build up. Gridding maps is tedious work. I wish the USGS would print the grid line on all of their maps. But even then, we would still need to grid our existing maps. As you can see this is not the kind of thing you want to do on the hood of a truck or using a flat rock. Grid your maps before you need them in the field! In a pinch you can fold the map over on itself and use the edge of the paper as a straightedge. Photocopies of Maps Frequently, you may use a photocopy of a small portion of a map rather than the entire map. This cuts down the wear and tear on the original map and allows several copies to be distributed among a group. Make sure you transfer at least the large-type portion of the UTM grid markings onto the photocopy. It's also helpful to provide scale and contour information. Preprinted scale bars on Post-It note paper are available or just make a copy of the scale bars and "cut and paste" Avoid the temptation to change the scale of the map with the zoom on the copier. If you use maps often you will have a good sense of distance. Alter the scale and it will be harder to judge distances. Plus your overlay tools will no longer be useful. If you do change the scale using the copier, be sure and copy the scale bars at the same time, so they will correctly reflect the new scale. If you are marking roads, trails or boundaries on the photocopied map, avoid obscuring the underlying feature with the mark. Pencil lines will usually allow the feature to show through as will highlighter pens. There is nothing more frustrating than needing to know what is under a big black mark on your copy of the map.

### USNG Coordinates Quick Guide — A Quick Guide to Using USNG Coordinates Standing at the center of the marker shown on the map below, a GPS unit set to display position in US National Grid format, would report a location of: Let's look at where the various parts of the USNG position come from on the map.
https://maptools.com/tutorials/usng/quick_guide

A Quick Guide to Using USNG Coordinates Standing at the center of the marker shown on the map below, a GPS unit set to display position in US National Grid format, would report a location of: Let's look at where the various parts of the USNG position come from on the map. The map has grid lines spaced every kilometer or 1000 meters. The grid is labeled with UTM coordinate values. But the same grid is used for both USNG and MGRS positions. When using USNG or MGRS the small type numbers to the left of the larger type numbers are replaced by the 100,000m Square ID. The vertical grid lines determine East-West position and the horizontal grid lines determine North-South position. Look along the bottom edge of the map at the labels for the vertical grid lines. The label, , reads "seven hundred and six thousand meters East." The label, , is an abbreviation for, The two grid lines are 1000 meters apart. The horizontal grid lines are labeled in a similar manner. The 10S is the Grid Zone Designation you are in. The Grid Zone is necessary to make the coordinates unique over the entire globe. The GJ is the 100,000 meter Square ID. It identifies a unique 100,000m square within the Grid Zone. The top set of numbers, 06832, represent a measurement of East-West position, within the 100,000 meter square, in meters. It's called an Easting. Using a map with a 1000m grid, the first two digits are come from the large type on the label for the grid line to the west of the position. The last 3 digits are the distance in meters measured from the western grid line. The bottom set of numbers, 44683, represent a measurement of North-South position, within the 100,000 meter square, in meters. It's called a Northing. Using a map with a 1000m grid, the first two digits are come from the large type on the label for the grid line to the south of the position. The last 3 digits are the distance in meters measured from the southern grid line. The USNG standard states that "A USNG reference is formally written as an entity without spaces, parentheses, dashes, or decimal points." I have not strictly followed this part of the standard in these tutorials. The inclusion of spaces to separate the logical parts of the coordinate string has been shown to facilitate the understanding and communication of coordinate strings between humans. I would encourage you to use spaces when writing USNG coordinate strings, and to pause briefly between logical parts when communicating USNG coordinate strings verbally. Truncated position formats for less precise positions The USNG format is designed to support measurement precisions of 1m, 10m, 100, 1,000m, and 10,000m. by truncating the grid coordinate values. 10S GJ 06832 44683 - Locates a point within a 1 meter square 10S GJ 0683 4468 - Locates a point within a 10 meter square 10S GJ 068 446 - Locates a point within a 100 meter square 10S GJ 06 44 - Locates a point within a 1,000 meter or 1 kilometer square 10S GJ 0 4 - Locates a point within a 10,000 meter or 10 kilometer square When all of the coordinates you are working with are localized within the same 100,000 meter square identifier, it is permissible to drop the Grid Zone Designator and the 100,000 meter square id. 06832 44683 - Locates a point within a 1 meter square 0683 4468 - Locates a point within a 10 meter square 068 446 - Locates a point within a 100 meter square 06 44 - Locates a point within a 1,000 meter or 1 kilometer square Note: It is easy to make an mistake using truncated position formats. Slipping a digit left or right results in a very different position. Worse, there is no visual clue that an error has been made, until the coordinate is plotted. Truncate, don't round When using less precise representation, it is important to truncate rather than round the Easting and Northing values. The Easting and Northing always refer to the southwest corner of the grid square. The size of square represented by a given coordinate will vary with the coordinate's precision. Truncating ensures the more precise squares will always remain within the less precise squares. Using various tools to plot and measure USNG positions on a map Click on the tab for the tool style you want to know more about. Grid Style Tool Slot Style Tool Corner Style Tool Mini Corner Style Tool Map Ruler Style Tool Using a grid style tool to plot/measure a UTM position with 100m precision Using a slot style tool to plot/measure a UTM position with 10m precision Using a corner ruler roamer style tool to plot/measure a UTM position with 10m precision Using a mini corner style tool to plot/measure a UTM position with 10m precision Using a map ruler to plot/measure a UTM position with 10m precision See these tools in motion The interactive tutorial animates the same work on a real topographic map, with the coordinates written as USNG. It starts where a USNG coordinate starts — at the map's reference box, showing where the grid zone and the 100,000 meter square letters come from — before it ever touches a tool: Read the USNG coordinate of a feature Plot a USNG coordinate onto the map The practice map is drawn on NAD 27 rather than the NAD 83 that USNG presumes, so the tutorial also shows the datum tag that difference requires. Switch its Datum control and both the answer and the tag change — see the two grids side by side. Learn more about... Map Datums and why they are so important Locating USNG grid information on USGS topographic maps Grid Zone Details The 100,000 meter square identifier letter pairs Metric Distance Measurements The small differences between USNG and MRGS Some of the history behind the military adoption of UTM and MGRS More than you probably want to know... Federal Geographic Data Committee - United States National Grid FGDC=STD-011-2001 (42 page pdf) National Geospatial Intelligence Agency Standardization Document, Universal Grids and Grid Reference Systems (101 page pdf)

### UTM Coordinate System Details — More details about the UTM coordinate system The Universal Transverse Mercator projection and grid system was adopted by the U.S.
https://maptools.com/tutorials/utm/details

More details about the UTM coordinate system The Universal Transverse Mercator projection and grid system was adopted by the U.S. Army in 1947 for designating rectangular coordinates on large scale military maps. UTM is currently used by the United States and NATO armed forces. With the advent of inexpensive GPS receivers, many other map users are adopting the UTM grid system for coordinates that are simpler to use than latitude and longitude. The UTM system divides the earth into 60 zones each 6 degrees of longitude wide. These zones define the reference point for UTM grid coordinates within the zone. UTM zones extend from a latitude of 80° S to 84° N. In the polar regions the Universal Polar Stereographic (UPS) grid system is used. UTM zones are numbered 1 through 60, starting at the international date line, longitude 180°, and proceeding east. Zone 1 extends from 180° W to 174° W and is centered on 177° W. Each zone is divided into horizontal bands spanning 8 degrees of latitude. These bands are lettered, south to north, beginning at 80° S with the letter C and ending with the letter X at 84° N. The letters I and O are skipped to avoid confusion with the numbers one and zero. The band lettered X spans 12° of latitude. A square grid is superimposed on each zone. It's aligned so that vertical grid lines are parallel to the center of the zone, called the central meridian. UTM grid coordinates are expressed as a distance in meters to the east, referred to as the "easting", and a distance in meters to the north, referred to as the "northing". Eastings UTM easting coordinates are referenced to the center line of the zone known as the central meridian. The central meridian is assigned an easting value of 500,000 meters East. Since this 500,000m value is arbitrarily assigned, eastings are sometimes referred to as "false eastings" An easting of zero will never occur, since a 6° wide zone is never more than 674,000 meters wide. Minimum and maximum easting values are: 160,000 mE and 834,000 mE at the equator 465,000 mE and 515,000 mE at 84° N Northings UTM northing coordinates are measured relative to the equator. For locations north of the equator, the equator is assigned the northing value of 0 meters North. To avoid negative numbers, locations south of the equator are made with the equator assigned a value of 10,000,000 meters North. Some UTM northing values are valid both north and south of the equator. In order to avoid confusion the full coordinate needs to specify if the location is north or south of the equator. Usually this is done by including the letter for the latitude band. If this is your first exposure to the UTM coordinate system you may find the layout of zones to be confusing. In most land navigation situations the area of interest is much smaller than a zone. The notion of a zone falls away, and we are left with a simple rectangular coordinate system to use with our large scale maps. Frequently, in land navigation, the zone information and the digits representing 1,000,000m, and 100,000m are dropped. The 1m, 10m and 100m digits are used only to the extent of accuracy desired. Note that it's the smaller digits that are dropped in the notation used by the USGS on the edges of their maps. For example 4282000 mN. becomes 82. Because pilots and sailors navigate over much greater distances they still favor the latitude longitude coordinate system. | Previous | Index | Next |

### UTM Corner Tools Tutorial — Using a UTM Corner Ruler A UTM Corner Ruler consists of two scales at right angles to each other.
https://maptools.com/tutorials/utm/corner_tools

Using a UTM Corner Ruler A UTM Corner Ruler consists of two scales at right angles to each other. UTM Corner Rulers will typically provide an additional digit of precision beyond a UTM Grid Overlay. On a 1:24,000 scale map you will be able to determine a position to within a 10m square. The trade off is that the Corner Ruler is somewhat harder to use. Start by placing the top right corner of the Corner Ruler on the SW corner of the UTM grid that contains the feature. The ruler edges should extend to the West and South. To find the UTM coordinates of a feature marked on your map slide the rulers North and East until the corner is on top of the feature to be measured. Read the UTM coordinate values from the starting grid lines. To locate a UTM coordinate on the map slide the ruler North and East until the desired distances are indicated at the grid lines. If the grid square you are using is on the edge of your map, you may need to start from a corner other than the southwestern one. You can still use the corner ruler, remember that UTM coordinate values increase from West to East and from South to North. You should return to the exercise and try it using a 1:24,000 scale UTM Corner Ruler. If you are using an odd scaled map or if you left your UTM tools behind, you can quickly make a simple corner ruler using the scale bars on the map. Start with the corner of a scrap of paper. Mark off a one kilometer distance and the 100m subdivisions using the metric scale bar. Repeat this process along the other edge. Number both rules starting from the corner which would be zero. Overlays containing UTM corner rulers for several different map scales are available from MapTools. The corner ruler is the harder tool to picture from a still image, so it may help to watch one work. The interactive UTM tutorial demonstrates the slot style tool, which carries the same pair of scales at right angles reading zero at the corner, and it places the tool honestly — landing on the grid line at the wrong spot first, checking that the scale really does span the full kilometer, and only then sliding into position: Measure a feature's coordinate Locate a coordinate on the map

### UTM Exercise Answers — You should have come up with the following results...
https://maptools.com/tutorials/utm/answers

You should have come up with the following results... Your plotted position should be just north of the 5784 elevation mark on Sawtooth Ridge. That would be 943 257 in 100m abbreviated format. 943 265 5400 ft level in Burnett Canyon 948 264 Dawson Spring 9375 2702 x5862

### UTM Grid Tools Tutorial — Using a UTM grid overlay tool If you want to find your location with more precision than is available from the grid lines on the map, you will need a tool that is marked in finer divisions.
https://maptools.com/tutorials/utm/grid_tools

Using a UTM grid overlay tool If you want to find your location with more precision than is available from the grid lines on the map, you will need a tool that is marked in finer divisions. One such tool is a grid overlay. The grid overlay is placed on the map with its edge aligned with the grid lines. Then the position of the mark can be determined using the tool's additional precision. Additional precision is available by either by "eyeballing" or by using a UTM Corner Ruler with finer markings. For many land navigation situations 100m precision is quite adequate. The example shown here locates the to a precision of 100m. The 10,000m and 1,000m digits of the coordinate are taken from the map. Thus the coordinates 59 82 locate the 1,000 meter square containing the star. The grid overlay is placed over the grid and the 100m digit is determined. Remember to read the Easting followed by the Northing. In 100m abbreviated format the coordinates of the are 597 821. The "pocket sized" UTM grid overlay shown here is available from MapTools. To watch a grid overlay used on a real topographic map, see the interactive UTM tutorial. It animates the tool sliding onto the grid square and squaring up to the grid lines, then reads the 100m digits off the printed scales: Plot a coordinate with a grid overlay Read a coordinate with a grid overlay

### UTM Metric Measurements — Metric Distance Measurements If the metric system gives you a headache, here are a few tips to help you out.
https://maptools.com/tutorials/utm/metric_measurements

Metric Distance Measurements If the metric system gives you a headache, here are a few tips to help you out. The Truth (to within 3 or 4 significant digits) What you can remember (You'll be about 10% too short.) 1 meter = 3.280 feet = 1.094 yards 1 meter ~= 3 feet ~= 1 yard 100 m = 109 yards 100 m ~= 100 yards ~= length of a football field 1000 m = 1 kilometer = 1 km = 0.621 miles ~= 5/8 mile 1000 m ~= 1/2 mile UTM, MGRS, and USNG coordinates give us locations that represent a square on the ground. The square could be as small as 1 meter on a side, or as big as 1,000 meters on a side. Here are some rough equivalents for some metric squares: 1 meter squareTwo doormats side by side 10 meter squareFour parking places 100 meter squareTwo football fields side by side 1,000 meter squareA city block

### UTM Practice Exercise — Try it out using your overlay and the following map...
https://maptools.com/tutorials/utm/exercise

Try it out using your overlay and the following map... Click on the map to get a pdf file containing this exercise. Your GPS unit reads... 10 S 0294324 3925702 Plot your position on the map. What would that be in 100m abbreviated format? Locate the following on the map... 943 265 948 264 9375 2702 Report the positions of the following symbols in 100m abbreviated format... Click here for answers. No overlay handy? The interactive UTM tutorial supplies the map and the tool on screen, and works each problem a step at a time. There are a dozen features to find on its practice map — try plotting a coordinate or reporting a feature's position.

### UTM Slot Tools Tutorial — Using a UTM Slot Style Tool • Position the base of the tool on the southern grid line.
https://maptools.com/tutorials/utm/slot_tools

Using a UTM Slot Style Tool • Position the base of the tool on the southern grid line. Slide the tool E-W until the target is centered in the slot. • Read the Easting value for the grid from the edge of the map. • Read the additional Easting digits from the E-W ruler where it crosses the western grid line. • Read the Northing value for the grid from the edge of the map. • Read the additional Northing digits from the N-S ruler where it crosses the target. Overlays containing UTM Slot Style Tools for several different map scales are available from MapTools. The interactive UTM tutorial runs these same steps as an animation on a real topographic map — the tool settling onto the southern grid line, the fit check against the northern line, then the slide E-W and the two scale readings: Read a coordinate with a slot style tool Plot a coordinate with a slot style tool

### UTM/MGRS Coordinates Quick Guide — A Quick Guide to Using UTM Coordinates Standing at the center of the marker shown on the map below, a GPS unit set to display position in UTM/UPS format, would report a location of: Let's look at where the various parts of the UTM position come from on the map.
https://maptools.com/tutorials/utm/quick_guide

A Quick Guide to Using UTM Coordinates Standing at the center of the marker shown on the map below, a GPS unit set to display position in UTM/UPS format, would report a location of: Let's look at where the various parts of the UTM position come from on the map. The map has grid lines spaced every kilometer or 1000 meters. The grid is labeled with UTM coordinate values. The vertical grid lines determine East-West position and the horizontal grid lines determine North-South position. Look along the bottom edge of the map at the labels for the vertical grid lines. The label, , reads "seven hundred and six thousand meters East." The label, , is an abbreviation for, The two grid lines are 1000 meters apart. The horizontal grid lines are labeled in a similar manner. The 10S is the Grid Zone Designation you are in. The Grid Zone is necessary to make the coordinates unique over the entire globe. The top set of numbers, 706832, represent a measurement of East-West position, within the Grid Zone, in meters. It's called an Easting. Using a map with a 1000m grid, the first digits are come from the label for the grid line to the west of the position. The last 3 digits are the distance in meters measured from the western grid line. The bottom set of numbers, 4344683, represent a measurement of North-South position, within the Grid Zone, in meters. It's called a Northing. Using a map with a 1000m grid, the first digits are come from the label for the grid line to the south of the position. The last 3 digits are the distance in meters measured from the southern grid line. Using various tools to plot and measure UTM positions on a map Click on the tab for the tool style you want to know more about. Grid Style Tool Slot Style Tool Corner Style Tool Mini Corner Style Tool Map Ruler Style Tool Using a grid style tool to plot/measure a UTM position with 100m precision Using a slot style tool to plot/measure a UTM position with 10m precision Using a corner ruler roamer style tool to plot/measure a UTM position with 10m precision Using a mini corner style tool to plot/measure a UTM position with 10m precision Using a map ruler to plot/measure a UTM position with 10m precision See these tools in motion The pictures above freeze a tool in its final position. If you'd rather watch it get there, the interactive UTM tutorial animates the whole sequence on a real topographic map — the grid lines sweeping in to bound the square, the tool sliding into place and squaring up to the grid, the digits being read off the scales, and the point finally marked. Step through it at your own pace, in either direction: Plot a UTM coordinate onto the map Read the UTM coordinate of a feature The precision of the Easting and Northing measurements A UTM coordinate's Easting and Northing are both distance measurements made in meters. But this leaves us with a dilemma when we have not measured with one meter precision. What to do with the unknown digits. Let's look at the Easting of a point that is 146m east of the western grid line. T hat would, in our example above, give it an Easting of 706146m E. But on a large scale map, no tool will be able to measure to the nearest meter. At best you'll get 10 meters, and if you're eyeballing it you'll be good to get 100m accuracy. But we still have to write all the digits down to the meter. The convention is to fill in the unknown/unmeasured digits with zeros, and to avoid any rounding up. So our easting becomes 706140m E or 706100m E. The trouble is we don't know if the location we are measuring was located with great accuracy at 706100m E, or if we just did a 100m rough measurement and the location could have an easting between 706100m E and 706199m E. One possible solution is to write the Easting an Northing in kilometers, using as many digits after the decimal point as we have measurement accuracy. For improved clarity, write the measurement units with the Easting and Northing In the world of map coordinates, there are a lot of different coordinate formats. If you just run a bunch of digits together with no spacing or units, you run the risk of having someone else misunderstand what coordinate format you are using. In the case of UTM, I suggest writing "m E" for "meters East" after the Easting, and "m N" for "meters North" after the Northing. When communicating a coordinate by voice, say the words "meters East" after the Easting and "meters North" after the Northing. There are several documented cases where a string of digits was passed, usually by voice, to someone else who misinterpreted the coordinate format. In one case this led to the rescue helicopter being sent 30 miles away from the actual incident. Learn more about... The interactive UTM tutorial — plot and read coordinates step by step Map Datums and why they are so important Locating MGRS grid information on USGS topographic maps Grid Zone Details Metric Distance Measurements UTM Practice Exercise Some of the history behind the military adoption of UTM and MGRS More than you probably want to know... National Geospatial Intelligence Agency Standardization DocumentUniversal Grids and Grid Reference Systems (101 page pdf) National Geospatial Intelligence Agency Standardization DocumentThe Universal Grids and the Transverse Mercator and Polar Stereographic Map Projections (86 page pdf)

### Video Tutorials — Video Tutorials - MapTools Video Tutorials Learn to use MapTools products with our instructional video library.
https://maptools.com/videos

Video Tutorials - MapTools Video Tutorials Learn to use MapTools products with our instructional video library. These tutorials cover coordinate systems, map reading, and navigation concepts. UTM Coordinates (1 video) Plotting UTM with a UTM Grid Tool How to plot a UTM coordinate using a UTM Grid Tool. Latitude / Longitude (2 videos) Measuring Lat/Lon How to measure latitude longitude coordinates from a map using a map ruler. Plotting Lat/Lon How to plot latitude longitude coordinates onto a map using a map ruler. < > Using Your Compass with a Map (6 videos) Introduction We've all been told to take a compass with us when we play in the woods. We know it will point to North. But what makes it really useful? Measuring Angles Most land navigation compasses measure angles in degrees. This tutorial shows you how to read a bearing from the compass dial. Sighting A Bearing Learn to hold your compass level and sight a bearing to a distant object. North References Part 1 Learn about the three common north references used in land navigation. True North -- Magnetic North -- Grid North North References Part 2 Learn how to convert between north references. North References Part 3 A few north reference conversion problems for you to try. < >

### Video: Compass Introduction — Compass Introduction - MapTools Video Tutorials > Using Your Compass with a Map > Introduction Using Your Compass with a Map: Introduction We’ve all been told to take a compass with us when we play in the woods.
https://maptools.com/videos/compass/intro

Compass Introduction - MapTools Video Tutorials > Using Your Compass with a Map > Introduction Using Your Compass with a Map: Introduction We’ve all been told to take a compass with us when we play in the woods. We know it will point to North. But what makes it really useful? Transcript Hi I’m John Carnes, founder of MapTools.com. Welcome to this MapTools training video series on Land Navigation, Using your Compass with a Map. We’ve always been told we should bring a compass when we play in the woods. Like somehow just having your compass with you will keep you from getting lost. Sure we all know a compass points north, but what else is is good for? The moss grows on the north side of the trees and all the other sides as well. But even the most basic “zipper pull” compass will point out North, and remind you where the other cardinal directions of, South, East, and West are. This feature alone should keep you from wandering in circles in the deep dark woods. Put your compass next to your map and you can rotate the map to line up with the surrounding terrain. This will allow you to match features shown on the map with the actual terrain. On a nice sunny day there are plenty of techniques for traveling cross country, you probably won’t need your compass. But when you combine hazardous terrain with poor visibility or darkness, a course leg described by a compass bearing is still one of the best techniques to use. With a bit of practice using your compass, you can learn to measure a bearing from your location to a distant object. When you plot this bearing onto your map, you bring your field observations into the context of your map. By sighting bearings on several features with known locations, and then plotting them onto your map, you can determine your location on the map. Or, suppose you can see a fire off in the distance, but you don't know where it is on the map. Use a compass to sight bearings from several different known locations. Plot these bearings onto the map, and they will intersect at the location of the fire. Both of these locating techniques, require us to use our compass to sight a bearing. But we also need to plot the bearing onto our map. You can use your compass for this as well. When you’re plotting or reading a bearing on the map, your compass is acting as a rather expensive protractor. Since it may be the only protractor you have with you in the field, this is a simple but valuable, skill to learn. When you sight a bearing with your compass, you’re most likely using Magnetic North as your starting point or north reference. But when you plot the bearing onto your map, you’ll probably want to use Grid North or True North as your starting point. You’ll need to understand all three north references, when to use them, and how to convert between them. The videos in this series will take you step-by-step through the techniques of land navigation, using your compass with your map. For more video tutorials on land navigation, visit the tutorial section of the MapTools.com web site. Enjoy you outdoor adventures. Related Products Compass Training Aid Declination Reference Card In This Series Introduction Measuring Angles Sighting a Bearing North References Part 1 North References Part 2 North References Part 3 All Video Tutorials

### Video: Measuring Angles with a Compass — Measuring Angles with Your Compass - MapTools Video Tutorials > Using Your Compass with a Map > Measuring Angles Using Your Compass with a Map: Measuring Angles Most land navigation compasses measure angles in degrees.
https://maptools.com/videos/compass/measuring-angles

Measuring Angles with Your Compass - MapTools Video Tutorials > Using Your Compass with a Map > Measuring Angles Using Your Compass with a Map: Measuring Angles Most land navigation compasses measure angles in degrees. This tutorial shows you how to read a bearing from the compass dial. Transcript Hi, John with maptools.com here to show you how to work with bearings on your map. The function of a magnetic compass is to measure the angle between the Earth's magnetic field and a target you have pointed the compass towards. All magnetic compasses have a magnetized element that is free to rotate and align itself with the Earth's magnetic field. It may be a simple needle or it may be a disk printed with cardinal directions and angular measurement markings. The most basic compasses are just marked with the cardinal directions: north, south, east, and west. In land navigation, when we use a compass to measure the angle between magnetic north, our location, and some other location, the measurement is made in units of degrees. The full circle is divided into 360 equal parts. North is defined as the starting point for the measurement and assigned the value of zero degrees. The measured angle increases in a clockwise direction. The cardinal direction of east has a value of 90 degrees, south is at 180 degrees, west is at 270 degrees, and we return to north at 360 degrees. Let's look at several typical compass dials. Here's a very typical compass dial. The dial is labeled every 20 degrees. It has longer tic marks every 10 degrees and a tic every two degrees. Here's a compass with a molded magnifier over the index line. The dial is labeled every 10 degrees has longer tic marks every five degrees, and a tic for every degree. On the other end, here's a low-cost compass. The dial is labeled every 30 degrees, it has longer tic marks every 10 degrees, and a tic only every five degrees. Let's try reading some bearings. On this compass, the dial is labeled every 20 degrees, longer tics every 10 degrees, and each short tic represents two degrees. The index mark on this compass is sharp, but it's hard to see because it's clear plastic. It does have a bit of phosphorescent paint which helps. The bearing here is 296 degrees. Your turn. What's the bearing in this image? How about the bearing in this image? Here's a compass with one of my favorite index lines. It's very thin and sharp, has a contrasting color, and touches the marks on the dial. The dial markings are inside the capsule so they are unlikely to wear off over time. The dial is labeled every 20 degrees, longer tic marks every 10 degrees, and each short tic is two degrees. What's the bearing? How about in this image? What's the bearing here? It's possible to read this dial with one degree accuracy, although it requires some judgment on your part. Here's the compass with the built-in magnifier over the index line. You'll notice this compass also has a different kind of needle. Remember, on this compass, the dial is labeled every 10 degrees, longer tics are every five degrees, and each short tic is one degree. What's the bearing in this image? With a bit of judgment on your part, it should be possible to read this dial with a half degree accuracy. I'd call the bearing in the second image here 357.5 degrees. Here's an example of a bad index line. Really there are two index marks. One of them is the arrow molded into the clear plastic above the dial, the other is a now very worn bit of phosphorescent paint, visible here through the center of the last zero in 300. The two index marks are not even lined up with each other. So the bearing is either 305 degrees or 306 degrees? Hard to tell. The markings on the dial and the index line don't get much ink on the reviews or on the packaging when you go to buy a new compass, but as you have seen, they make a big difference in accuracy and ease of use. Related Products Compass Training Aid Declination Reference Card In This Series Introduction Measuring Angles Sighting a Bearing North References Part 1 North References Part 2 North References Part 3 All Video Tutorials

### Video: Measuring Latitude/Longitude — Measuring Lat/Lon Coordinates - MapTools Video Tutorials > Measuring Lat/Lon Coordinates Measuring Lat Lon Coordinates with a Map Ruler Transcript Using a map ruler designed specifically for the USGS 1:24,000 scale map series, you can easily determine the latitude longitude coordinates of a point on the map.
https://maptools.com/videos/latlon/measuring

Measuring Lat/Lon Coordinates - MapTools Video Tutorials > Measuring Lat/Lon Coordinates Measuring Lat Lon Coordinates with a Map Ruler Transcript Using a map ruler designed specifically for the USGS 1:24,000 scale map series, you can easily determine the latitude longitude coordinates of a point on the map. Start by locating the 2.5 minute grid that contains the point of interest, in our example the red star. Remember that the United States is in the northern and western hemispheres. Thus latitude values increase from south to north, and longitude values increase from east to west. The right to left increase of longitude is often counterintuitive to beginning navigators. In our example, the red star is north of the 38° 2' 30" parallel by a few minutes. It is not as far north at the 38° 5' parallel. It is also a few minutes west of the 119° 55' meridian, but not as far west as 119° 57' 30". We will start by measuring the latitude, which is the easiest of the two to measure. You will measure how much farther north the point is from the known parallel to the south. Place the zero end of the map ruler on the southern parallel. The 2.5 minute end should touch the next parallel to the north. Note that one edge of your ruler is marked in minutes and seconds, while the opposite edge is marked in decimal minutes. Use the edge that matches the coordinate format you are using. Slide the ruler east or west until it touches the point of interest. Measure the number of minutes and seconds further north to the point of interest. In our example, the point is 1' and 20" north of the southern parallel. Add this measurement to the latitude of the southern parallel to get the latitude of the point of interest. In our example the southern parallel has a latitude of N 38° 2' 30". So the latitude of our point is N 38° 3' 50" Measuring the longitude is not quite as easy. If you place the ruler horizontally in the grid, the ruler extends past the edge of the grid. It's too long. This is because the meridians of longitude move closer together as you move away from the equator. The solution is to place the ruler diagonally between the two meridians. This effectively scales the ruler to fit. Keep the ends of the 2.5 minute ruler on the meridians, and move the ruler vertically until it touches the point of interest. Read from the ruler where the point touches it, to determine the number of minutes and seconds west of the eastern meridian. Add this measurement to the longitude of the eastern meridian to get the longitude of the point of interest. In our example, the point of interest is 1' 50" west of the eastern meridian at W 119° 55', so the resulting longitude is W 119° 56' 50" To reach some points in the grid it may be necessary to use the ruler on the other diagonal or to extend the end of the ruler above or below the grid, while still keeping the ruler ends on the 2.5' meridians. We now have the latitude longitude coordinates of the point of interest, N 38° 3' 50" W 119° 56' 50" We could now proceed to store these coordinates into our GPS unit, and use it to assist us in navigating to the point. Related Products Map Ruler for 1:24,000 Scale Maps Latitude Longitude Tool Other Video Tutorials Plotting Lat/Lon Coordinates All Video Tutorials

### Video: North References Part 1 — North References Part 1 - MapTools Video Tutorials > Using Your Compass with a Map > North References Part 1 North References Used in Land Navigation: Part 1 The three common north references — True, Magnetic, and Grid — and when each is used.
https://maptools.com/videos/compass/north-references-part1

North References Part 1 - MapTools Video Tutorials > Using Your Compass with a Map > North References Part 1 North References Used in Land Navigation: Part 1 The three common north references — True, Magnetic, and Grid — and when each is used. North References is one of the more challenging topics in land navigation. This part introduces the three north references you will work with — True North, Magnetic North, and Grid North — and explains why each one matters. For a deeper written walkthrough of how these references relate, see the online North Reference tutorial, or design your own printable declination reference sheet. Continue with Part 2 for converting between the north references, and Part 3 for worked practice problems. Related Products Compass Training Aid Declination Reference Card In This Series Introduction Measuring Angles Sighting a Bearing North References Part 1 North References Part 2 North References Part 3 All Video Tutorials

### Video: North References Part 2 — North References Part 2 - MapTools Video Tutorials > Using Your Compass with a Map > North References Part 2 North References Used in Land Navigation: Part 2 Converting a bearing between True, Magnetic, and Grid North using a declination diagram.
https://maptools.com/videos/compass/north-references-part2

North References Part 2 - MapTools Video Tutorials > Using Your Compass with a Map > North References Part 2 North References Used in Land Navigation: Part 2 Converting a bearing between True, Magnetic, and Grid North using a declination diagram. This part covers converting a bearing between the three north references using a declination diagram. Because a compass reads bearings relative to Magnetic North while a map is drawn relative to Grid or True North, converting between them is an essential land-navigation skill. For a step-by-step written explanation, see the online North Reference tutorial, or build a printable declination reference sheet for your area. When you’re ready to practice, work through the five conversion problems in Part 3. Related Products Compass Training Aid Declination Reference Card In This Series Introduction Measuring Angles Sighting a Bearing North References Part 1 North References Part 2 North References Part 3 All Video Tutorials

### Video: North References Part 3 — North References Part 3 - MapTools Video Tutorials > Using Your Compass with a Map > North References Part 3 North References Used in Land Navigation: Part 3 – Practice Problems Five worked north-reference conversion problems.
https://maptools.com/videos/compass/north-references-part3

North References Part 3 - MapTools Video Tutorials > Using Your Compass with a Map > North References Part 3 North References Used in Land Navigation: Part 3 – Practice Problems Five worked north-reference conversion problems. Pause the video to solve each one, then play on to check your answer. Transcript This video presents 5 north reference conversion problems for you to solve. Each problem will state the conversion to be preformed and provide a declination digram to use. If you want to solve the problem on your own, pause the video, do the conversion, and then continue playing the video to see the solution. The problems will explore different combinations of Grid and Magnetic North on either side of True North. They will also get a bit trickier as they progress. Once you feel that you have the hang of this, I’d suggest you dig out a map of your local area and try a few north reference conversions using your declination values. Problem 1 Convert a bearing of 285° Grid to a Magnetic bearing. Remember, when you are working with the declination diagram, bearings increase in a clockwise direction. Magnetic North is 16 degrees East of True North. Grid North is 1.5 degrees East of True North. The angle between Grid North and Magnetic North is the 16 degrees from Magnetic to True, less the 1.5 degrees from True to Grid, or 14 and a half degrees. Let’s round that up to 15 degrees. Now draw the 285° Grid bearing onto the diagram. Start at Grid North and go in a clockwise direction. The answer we are seeking is the angle from Magnetic North to the target. In this case the Magnetic bearing we are seeking is smaller than the Grid bearing we were given. So we subtract 15° from the 285° Grid value to get the answer of 270° Magnetic. Now lets make our short cut rules for this situation. Problem 2 Convert a bearing of 67° Magnetic to a True bearing. Magnetic North is 12 degrees West of True North. Grid North is 1 degree 42 minutes West of True North. The angle between True North and Magnetic North is 12 degrees. Draw the 67° Magnetic bearing onto the diagram. The answer we are seeking is the angle from True North to the target. In this case the True bearing we are seeking is smaller than the Magnetic bearing we were given. So we subtract the 12° difference from the 67° Magnetic value to get the answer of 55° True. Problem 3 Convert a bearing of 108° Grid to a Magnetic bearing. Magnetic North is 9 degrees East of True North. Grid North is 25 minutes East of True North. The angle between Grid North and Magnetic North is the 9 degrees from Magnetic to True, less the 25’ minutes from True to Grid. That would be 8 degrees 35 minutes, which we’ll round up to 9°. Draw the 108° Grid bearing onto the diagram. The answer we are seeking is the angle from Magnetic North to the target. In this case the Magnetic bearing we are seeking is smaller than the Grid bearing we were given. So we subtract the 9° from the 108° Grid value to get the answer of 99° Magnetic. Problem 4 Convert a bearing of 11° Grid to a Magnetic bearing. Magnetic North is 18 degrees East of True North. Grid North is 1 degree 15 minutes East of True North. The angle between Grid North and Magnetic North is the 18 degrees from Magnetic to True, less the 1° 15’ from True to Grid. That would be 16° 45’, which we’ll round up to 17°. Draw the 11° Grid bearing onto the diagram. The answer we are seeking is the angle from Magnetic North to the target. Remember the angle need to go clockwise from Magnetic North to the target bering. In this case the Magnetic bearing we are seeking is smaller than the Grid bearing we were given. So we subtract the 17° from the 11° Grid value. This gives us a result of minus 6 degrees. Bearings need to be given in terms of a 0 to 360 degree circle. So add 360° to the -6° to get the answer of 354° Magnetic. Problem 5 Convert a bearing of 350° Magnetic to a Grid bearing. Magnetic North is 14 degrees East of True North. Grid North is 1 degree 45 minutes West of True North. The angle between Grid North and Magnetic North is the 14 degrees from Magnetic to True, plus the 1° 45’ from True to Grid. That would be 15° 45’, which we’ll round up to 16°. Draw the 350° Magnetic bearing onto the diagram. The answer we are seeking is the angle from Grid North to the target. In this case the Grid bearing we are seeking is larger than the Magnetic bearing we were given. So we add the 16° to the 350° Grid value. This gives us a result of 366 degrees. Bearings need to be given in terms of a 0 to 360 degree circle. So subtract 360° from the 366° to get the answer of 6° Magnetic. Related Products Compass Training Aid Declination Reference Card In This Series Introduction Measuring Angles Sighting a Bearing North References Part 1 North References Part 2 North References Part 3 All Video Tutorials

### Video: Plotting Latitude/Longitude — Plotting Lat/Lon Coordinates - MapTools Video Tutorials > Plotting Lat/Lon Coordinates Plotting Lat/Lon Coordinates How to plot latitude longitude coordinates onto a map using a map ruler.
https://maptools.com/videos/latlon/plotting

Plotting Lat/Lon Coordinates - MapTools Video Tutorials > Plotting Lat/Lon Coordinates Plotting Lat/Lon Coordinates How to plot latitude longitude coordinates onto a map using a map ruler. Transcript Plotting latitude longitude coordinates onto a map is essentially the reverse of the process used to measure the coordinates of a point of interest. As an example, suppose at our current position, our GPS receiver displays coordinates of N 38° 3' 50" W 119° 56' 50". First we need to locate the 2.5 minute grid that contains this coordinate. The latitude falls between the 38° 2' 30" and the 38° 5' parallels and the longitude falls between the 119° 55' and the 119° 57' 30" meridians. Subtract the latitude provided by the GPS from the latitude of the southern parallel to determine that the point is 1' and 20" further north. Subtract the longitude provided by the GPS from the longitude of the eastern meridian to determine that the point is 1' 50" further west. It's this subtraction of minutes and seconds that makes using the decimal minute notation favorable. Using the map ruler measure up from the southern grid line 1' 20". Make this measurement at the left and right edges of the grid, placing a small tic mark on each. Then draw a light line across the grid at the desired latitude. The point to be plotted lies along this line. Use the map ruler to measure 1' 50" west of the eastern meridian. The map ruler will need to be placed on a diagonal and moved up or down until the 1' 50" mark crosses the line of latitude you drew in the previous step. This is the location described by the GPS coordinates. Related Products Map Ruler for 1:24,000 Scale Maps Latitude Longitude Tool Other Video Tutorials Measuring Lat/Lon Coordinates All Video Tutorials

### Video: Sighting a Bearing — Sighting a Bearing with Your Compass - MapTools Video Tutorials > Using Your Compass with a Map > Sighting a Bearing Using Your Compass with a Map: Sighting a Bearing Sighting a bearing is the technique of measuring the angle between Magnetic North, your location, and a distant object.
https://maptools.com/videos/compass/sighting-bearing

Sighting a Bearing with Your Compass - MapTools Video Tutorials > Using Your Compass with a Map > Sighting a Bearing Using Your Compass with a Map: Sighting a Bearing Sighting a bearing is the technique of measuring the angle between Magnetic North, your location, and a distant object. Transcript When we use our compass to “sight a bearing”, we are measuring the angle between Magnetic North, our location, and a distant object. Hold the compass with both hands. Position the compass in front of your body at a comfortable arms length and at about eye level. Hold the compass level. The compass should be level from side to side. This is easy to see. You also need to hold the compass level front to back. With the sighting notch at eye level, the base plate will be just below eye level and you should be able to see just a bit of the top of the baseplate. If you see a lot of the bottom or top of the baseplate, your compass is not level. Finally you need to line up your eye, the needle pivot point and the sighting notch. Use your wrist to rotate the compass on the vertical axis, until the black line in the mirror, is aligned with the pivot point of the needle. The base of the compass should now be level, and the magnetic needle should be free to move. Adjust the flip up mirror so that the magnetic needle and the orienting arrow is visible. The mirror will be about 45° from the base plate of the compass. Now that we have the compass level, the magnetic needle will align itself with the Earth’s magnetic field, pointing towards the Magnetic North Pole. We’re ready to point the compass at the distant object. Turn your entire body, holding the compass in your hands, until the distant object you are sighting is aligned with the sighting mechanism on your compass. Let’s look at that from eye level. Next, look in the mirror and turn the dial of the compass until the magnetic needle is parallel to the edges of the orienting arrow on the base of the capsule. Depending on your viewing angle the needle may not appear to be centered in the orienting arrow. This is not a problem as long as the needle is parallel to the edges of the arrow. Again lets look at that from eye level. Recheck that your compass is still aligned with the distant object. It is usually necessary to make several fine adjustments of the compass position and dial rotation before you will be satisfied that you have everything adjusted correctly. You can relax your stance, open the mirror, and hold the compass at a comfortable distance to read the bearing at the index line. When you write the bearing down, follow it with the letter “M” or the abbreviation “Mag.” to indicate that the angle was measured using Magnetic North as the 0° reference. When you relay the bearing verbally, make sure you say the word “magnetic” following the angle. In our example we would say, “62 degrees magnetic.” Some compasses can be adjusted to read bearings relative to the other north references. Information on how to adjust your compass and when you might want to do this, can be found in the Understanding North References video in this series. Related Products Compass Training Aid Declination Reference Card In This Series Introduction Measuring Angles Sighting a Bearing North References Part 1 North References Part 2 North References Part 3 All Video Tutorials

### Video: UTM Plotting with Grid — Plotting UTM with a UTM Grid Tool - MapTools Video Tutorials > Plotting UTM with a UTM Grid Tool Plotting UTM with a UTM Grid Tool How to plot a UTM coordinate using a UTM Grid Tool.
https://maptools.com/videos/utm/plotting-with-grid

Plotting UTM with a UTM Grid Tool - MapTools Video Tutorials > Plotting UTM with a UTM Grid Tool Plotting UTM with a UTM Grid Tool How to plot a UTM coordinate using a UTM Grid Tool. Transcript Hi. John with MapTools.com here to show you how to plot a UTM coordinate from your GPS, onto your map using a UTM Grid tool. The most common thing I do with my GPS receiver is using it to check my current location on my map. I pull the GPS out of my pack, turn it on and get my coordinates. With a quick plot onto my map, I've confirmed my location, and I'm done with the GPS. Here is my GPS displaying the coordinate I am going to show you how to plot onto a map. It's a UTM coordinate. UTM stands for Universal Transverse Mercator, and that's the easiest coordinate system to work with in the field. I've already set my GPS receiver to display UTM/UPS coordinates, and I've told it to use the NAD27 CONUS map datum which matches the map we will be using. The map I'm working with is a United States Geological Survey 1:24,000 scale topographic map titled Sharktooth Peak, California. If we look at the fine print at the lower left corner of the map. We can confirm that the map has a 1000 meter UTM grid for zone 11, printed on it and that the map is based on the 1927 North American Datum, or NAD27 CONUS on the GPS setup menu. Most maps of locations in the continental United States will use one of three map datums; NAD27, NAD83, or WGS84. It's important that your GPS setting match the datum used by your map. The first step in plotting our coordinate, is to locate the 1000 meter grid square defined by the UTM coordinate. Let's look at the UTM coordinate more closely. The 11S is the zone number and latitude band letter. This part is necessary to make this coordinate a unique location on a global scale. Unless you are working with coordinates that cover a very large area, you can usually ignore the zone. The remaining top number represents a distance measured from west to east in meters, and is called the “easting.” The bottom number represents a distance measured from south to north in meters, and is called the “northing.” To help understand which digits are used to locate the 1000 meter grid square on the map, let's write the number 1000 below both the easting and the northing. The digits from the thousands place and larger are used to locate the grid square on the map. The coordinates indicate that we are in the 1000m grid that begins at three hundred and nineteen thousand meters east and four million one hundred and forty five thousand meters north. Let's find the grid square on the map. Looking at the top edge of the map, starting on the left side, we see the first UTM grid line is labeled three hundred thirteen thousand meters east. The next line to the east has an abbreviated label for three hundred fourteen thousand meters. We are looking for the three hundred nineteen thousand meters east grid line. 315 … 316 … 317 … 318 … There it is, Three hundred nineteen thousand meters east. Our coordinate is located in this 1000m band between three hundred nineteen thousand meters East and three hundred twenty thousand meters East. Now let's move to the lower right corner of the map. The first UTM grid line going up the right side of the map is labeled four million one hundred thirty nine thousand meters north. The next line to the north has an abbreviated label for four million one hundred forty thousand meters north. We are looking for the four million one hundred forty five thousand meters north grid line. 4141 … 4142 … 4143 … 4144 … There it is, four million one hundred forty five thousand meters north. Our coordinate is located in this 1000m band between four million one hundred forty five thousand meters North and four million one hundred forty six thousand meters North. Our coordinate is located in the 1000m grid square where these bands intersect. Now it's time to locate the coordinate within the grid square. If we look at the coordinate again, we see that the point we are interested in is 174m east and 312m north of the western and southern edges of the grid. We could estimate that distance within the grid. But instead, I'm going to show you how quick and easy it is to use a grid reader. We are going to use a 1:24,000 scale UTM grid reader from MapTools.com. The 1:24,000 scale of the tool matches the scale of our map, and the tool is designed to work with a 1000m grid square. Place the tool onto the map and align it with the grid square we just located. Double check that the grid on the tool fits the 1000m grid square on the map. The grid reader divides the 1000m square into 100m squares. A 100m square is the size of two soccer fields side by side. We use the hundreds digit from the easting and northing to locate the 100m square identified by our coordinate. In this case that would be 100m east and 300m north. The 100m grid square we want is at the intersection of the 100m column and the 300m row on the grid tool. Avoid the temptation to round the coordinate to the closest 100m value. That will put you in the wrong 100m square about half the time. Sometimes you will want to know your location with more precision than just “two soccer fields.” We can use the 10m digits from our coordinate to estimate position within the 100m square. For our coordinate that would be 70m east and 10m north. Each 100m square has a dot in the center 50m from each edge. Use that dot to help estimate position within the 100m square. The 1m digits in our coordinate represent such a small mark on our map that they are rarely used when plotting. To place a mark on the map, take a mental snapshot of the point's location with respect to the map markings, move the tool out of the way, and then make the mark in the correct position. In many situations you do not need to mark the map. Just visually confirming your location on the map is sufficient. The UTM grid reader is an easy tool for a beginner to understand and use. But, if you find that you often need more than 100m precision or that you want to be able to more easily make a mark on the map, you should check out the slot style UTM tools from MapTools.com. Related Products UTM Grid Tool for 1:24,000 Scale Maps UTM Corner Tool Other Video Tutorials Measuring Lat/Lon Coordinates Compass Introduction All Video Tutorials

### What's New at MapTools — Quantity Pricing for Custom Rulers July 2026 Custom rulers now come with automatic quantity discounts.
https://maptools.com/whats_new

Quantity Pricing for Custom Rulers July 2026 Custom rulers now come with automatic quantity discounts. A single ruler is still $8.95, but the per-ruler price starts dropping with your second ruler and tapers all the way down to $4.50 each on orders of 50 or more. The discount counts every custom ruler in your order, not just copies of one design — mix five different scales, or five copies of the same design, and both count toward the same price break. The simple ruler designer and the advanced designer now show the full price table as you design, along with how many more rulers reach the next break. And because the discount is order-wide, adding rulers can lower the price of rulers already in your cart. Outfitting a team or a class? Browse the ready-made community tools and collections and add a whole matched set to your cart in one click. Interactive UTM Tutorial July 2026 Working with map coordinates is easier to show than to tell. Our new interactive UTM tutorial walks you through plotting and reading UTM coordinates step by step, animated on a real topographic map. Pick a problem and watch each move happen — finding the grid square, placing the tool, reading the scales — with every step explained on screen, at your own pace. The tutorial demonstrates both styles of coordinate tool we make: the UTM grid overlay and the slot-style corner scale. It speaks MGRS and USNG as well as UTM, and it can even draw the NAD27 and WGS84 map datums side by side, so you can see exactly why the datum printed on your map matters. Start with plotting a coordinate with the grid overlay, or try reading a coordinate with the corner scale. Ask the MapTools Knowledge Base June 2026 Have a question about coordinates, declination, map scale, or how to use one of our tools? Our new Knowledge Base lets you ask in plain English and get a straight answer drawn from years of MapTools instruction. Type a question the way you'd ask a person — “how do I plot a UTM coordinate?” or “what's the difference between true north and magnetic north?” — and you'll get a clear, focused reply. It's free to use, no account required. Give the Knowledge Base a try. The Instructor's Corner June 2026 If you teach land navigation, the new Instructor's Corner is for you. It gathers core topics, exercises, teaching aids, and articles from the MapTools knowledge base into one place built for instructors — including notes on the misconceptions students stumble over and how to teach around them. Visit the Instructor's Corner to take a look. Coordinate Converter Tool Now Available May 2026 If you work with maps, GPS devices, or navigation tools, you probably work with coordinates. The challenge is that coordinates come in many different formats: decimal degrees, degrees and decimal minutes, degrees minutes seconds, UTM, MGRS, and USNG. Each system has its strengths, and sometimes you need to convert from one format to another. That's where our new coordinate converter tool comes in. The converter is fast and real-time. As you type or paste a coordinate in any supported format, it automatically detects what you've entered and displays the conversion to five other formats. It supports four datums: WGS84, NAD83, NAD27, and auto-detection. Copy any of the converted formats to your clipboard with a single click. Whether you're plotting points on a topographic map, entering coordinates into a GPS unit, reading a military grid reference, or working with survey data, the converter makes it easy to move between the coordinate systems your various tools require. The tool accepts coordinates in six different input formats: Decimal Degrees (DD), Degrees Decimal Minutes (DMM), Degrees Minutes Seconds (DMS), UTM, Military Grid Reference System (MGRS), and U.S. National Grid (USNG). No matter how your coordinates are formatted, the converter understands them. Try the coordinate converter today and see how much time it saves. A New MapTools Website April 2026 The site you're reading this on is brand new. We've replaced the PHP storefront that served maptools.com for many years. The old code had grown crusty enough that adding the features we wanted was getting harder than starting fresh. The headline feature is our new advanced custom ruler designer. The 2018 simple ruler designer let you pick one scale per edge from a fixed list. The new designer lets you put 17 different measurement scales onto your ruler, combine multiple scales on a single ruler, and arrange them however you need. If you've ever wanted a 1:31,680 ruler with statute miles along one edge and decimal-minute latitude along another, you can now build that yourself. The other big addition is customer accounts. With an account you can: See your complete order history Save and revisit the custom tools you've designed in your design library Share custom tool designs with teammates, or organize them into collections Save shipping addresses and preferences so checkout is faster next time None of this is required — you can still place an order as a guest, same as before. But if you're a frequent customer, designing tools for a team, or just want to reorder a custom design six months from now without redoing the work, the account is here for you. First Price Update in 8 Years, and Changes to International Shipping February 2026 We held our prices steady for 8 years. That's been a quiet point of pride around here. But paper, ink, postage, and pretty much everything else costs more than it did in 2018, and so this month we adjusted prices for the first time since then. The increases are modest and bring us back into line with what it actually costs to make and ship our tools. At the same time, we've changed how we handle international shipping. The short version: we're no longer shipping internationally directly through the shopping cart, except in rare cases. The longer version is on our international orders page — it's a story of postal-service rule changes, lost shipments, surprise duty bills from FedEx and UPS, and Amazon fulfillment hurdles that are too tall for a two-person company to clear. If you're an international customer who'd still like to get tools from us, please reach out. We can usually find a way to get a small order to you, but the terms are different now and we want to talk through them up front so there are no surprises. Ten Years with the Rebelle Rally October 2025 This year was the 10th edition of the Rebelle Rally, and we've been there for every one of them. The Rebelle is a women's off-road navigation rally — no GPS, no internet, just a map, a compass, paper coordinates, and a real off-road vehicle headed across the desert. It's the kind of event our tools were made for, and it's been a privilege to outfit teams running it since the very first year in 2016. The Rebelle is a lat/lon-only event, so what competitors need from us is map rulers with latitude and longitude scales matched to the maps the rally hands out, built to hold up to dust and sweat and to work fast under time pressure. A lot of what we've built over the past decade — and a lot of what we're working on next — has been shaped by what we've learned from the Rebelle and from the teams that compete in it. We have some new rally-specific tools in the works for the years ahead. More on those when they're ready. 4th Edition of the UTM Guide 2024 We've released the 4th edition of "Using your GPS with the UTM Map Coordinate System". The 3rd edition was 50 pages; the 4th is 89. The new material includes: A chapter on finding maps with UTM coordinate grids — where to look and what to expect A chapter on using GPS waypoints — entering them, recording them, and getting them between your map and your device A chapter on how to use a map without a coordinate grid — because not every useful map comes with one And, finally, an index — three editions in, this is overdue and I know it If you've worked through earlier editions, the 4th edition isn't a rewrite of what you already have — it's mostly additions and clarifications. If you're new to UTM, this is the edition I'd start with. UV Inkjet Printer and Laser Cutter 2022 In 2021 we added two pieces of equipment that have changed what we can make: a laser cutter and a UV inkjet printer. Together they let us print and cut tools in-house, in small runs, at a quality we couldn't get any other way. Before this, every new tool design needed a minimum order of a few thousand units from a commercial print shop. Now we can make a hundred — or one — of something and see how it does. The new equipment opened the door to a wave of new tool designs, including: RoundGTAQuads UTMGrid12 — a 1:12,000 scale grid overlay A 1:31,680 grid tool PocketSlotsQuads It also gave us a family of large classroom training aids — oversized "-TA" versions of our regular tools that an instructor can hold up in front of a class to demonstrate how the small student version works. The current lineup: Compass-TA — large compass MapRuler-TA — large map ruler CornerRuler-TA — large corner ruler MiniCorner-TA — large mini corner UTMGrid-TA — large UTM grid overlay UTMSlot-TA — large UTM slot tool And it let us bring a number of low-volume products in-house — products that previously had to be retired between large reorders. These now get made as we need them: MyTopo-1 UTM-BC UTM-TI UTM-MK AdvCorner UTMGrid100 UTM-TH LandSection24 It also means we can take on one-off custom tool jobs that wouldn't have been practical before. If you've got an unusual map, an unusual scale, or a project that needs something we don't already make, this is the kind of work the new equipment was bought to do. Custom Map Rulers for Any Map Scale May 2018 I'm excited to announce our new custom map rulers. This is something that I've been working towards for a couple of years now. I've written the code to both draw the rulers and to allow you to design your customized ruler. I've also modified our shopping cart so that it's able to track orders for custom tools. You can create a map ruler for any map scale you may encounter. The four long edges of the ruler will have scales for measuring: Latitude in Degrees, Minutes and Seconds, or Degrees and Decimal Minutes, or Decimal Degrees Longitude for a specified latitude. No more need to use the latitude scale at an angle! Miles statute or nautical, and divided into decimal or fractional subdivisions. Kilometers The rulers we print and send you will be somewhat different from our stock rulers. It will be printed on Rite-In-The-Rain™ card stock instead of plastic. It will be an inch and a half wide instead of one inch. This makes room for you to add a personalized label on each side. In the future, I'm working on a page that will allow you to create even more customized rulers. You'll be able to choose from 17 different measurement scales on each of the four long edges. You'll be able to combine multiple scales on a single ruler. Custom Declination Reference Sheets June 2017 As a first step in being able to provide customized tools, I am pleased to announce that we are now making customized declination reference sheets. Input you zip code our your latitude and longitude, and you north reference preferences, and we'll make you a reference sheet showing the current magnetic declination, the grid variance, and instructions for compass set up, converting bearings between different north references and plotting bearings onto your map. We are printing these sheets on Rite-In-The-Rain paper, so they will stand up to field use. Currently, we are including a free declination reference sheet, with every domestic order. We're basing the location for the sheet on the shipping zip code. If you want a tool for a different location, or for north reference preferences that differ from our default selection, you can design you own declination reference sheet. Redesigned Website and New Content November 2013 We hope you like the new look and feel. But more important we hope we have made things easier to find. We have done a lot of work on our product images and descriptions to give you an even better idea of what they can do and how they work. In the process, we fixed a ton of spelling and grammar stuff. But I'm a computer science guy, not an english major, so I'm sure we missed more than a few. There is a new tutorial on North References for Navigating with a Map, Compass and GPS. Much of the hard work is under the hood. We've ripped out a lot of crufty html code that caused grief for various browsers. We put in an engine that should allow for lots of future innovation that we already have in the pipeline. Next up we'll be working on the shopping cart. We plan to support a more flexible pricing structure for folks that are buying tools for their entire team. We are also taking the baby steps towards fully customizable tools. More and more often the best map of the area, is not published by USGS. And more often than not is in a scale that the cartographer chose to fit the area onto the paper, with no need to match the scales of an entire map series. New 1:24,000 Scale Slot Style Tools A "pocket sized" and a "credit card sized" tool with a 1:24,000 slot ruler are new additions to our product line. Both feature a band of opaque white to make reading and finding the tool easier. UTMSlot24 UTM-SC24 Improvements to the Improved Military Style UTM/MGRS Tool We have added a band of white ink the two compass roses. This makes reading the compass rose easier and also keeps the tool from "disappearing" when you place it on the map. SuperGTA Improvements to the UTM Grid Overlays for 1:24,000, 1:25,000 and 1:50,000 We have added a band of white ink around the edge of the 1:24,000, 1:25,000 and 1:50,000 scale grid overlays. This makes reading the compass rose and grid numbers easier and also keeps the tool from "disappearing" when you place it on the map. In the center of each 100m square, on the 1:24,000 and 1:25,000 scale tools, we've added a small dot, which makes it easy to read the coordinate with a 50m precision. One last thing, we also added a lanyard hole in the upper left corner. UTM Grid Overlays Video Tutorials Two new Video Tutorials on measuring and plotting latitude longitude coordinates using a MapRuler.

### Wholesale Purchasing — MapTools Reseller Information New pricing effective Feb, 1, 2026 The 2026 wholesale price list is available for download as a PDF document.
https://maptools.com/wholesale

MapTools Reseller Information New pricing effective Feb, 1, 2026 The 2026 wholesale price list is available for download as a PDF document. Here at MapTools we understand that many of you bring value to our products by exposing them to folks who might not otherwise know about them, and that you make them available in marketplaces that we could not reach on our own, and we welcome that approach to reselling our products. Some examples of resellers that add value include: Brick and Mortar Retail Stores Online stores attached to websites targeting specific user groups. Instructors that sell or provide our products as part of their classes. Defense and public sector contractors specializing in linking government purchasers and contracts with products and vendors like ourselves. We are much less interested in resellers that simple resell on large online marketplaces like Amazon or EBay. If this is what you do, and you still think we should value you as a reseller, please provide us with a detailed explanation of the value you bring to the table. If you are an end user of large quantities of our products, you should take advantage of our existing quantity price breaks or contact us to negotiate quantity price breaks specific to your needs. MapTools has two simple requirement to be met by folks wishing to resell our products. First, we ask that you be engaged in an ongoing "value added" resale business with the intent to resell our products in the future. Please provide us with a short description of how and where you intend to resell our products. Second, we ask that your first order total $100 or more at wholesale pricing, which is typically 50% off of retail. There is no minimum on subsequent orders. This is a small hurdle for most serious resellers, but we keep it that way, because we really do appreciate what it takes to be a small retail store and that you are making a serious commitment just to make physical space for our products in your inventory. We'll evaluate your request and try to let you know in a timely manner if we think you are a good fit and are approved. Additionally Net 30 day credit terms are available upon credit approval. A credit application is needed to start the credit approval process An old catalog is available for download as a pdf document, pricing is out of date. We will be happy to drop-ship orders for you. But we will charge a $5.00 per order drop-ship fee. Most of our products are available with either minimal packaging or in retail packaging in a poly bag with a hang tag and UPC bar code. Let us know what packaging works best for you when you place an order.

### Why Use UTM? — Why Use UTM Coordinates The UTM coordinate system offers the following benefits: A square grid UTM Provides a constant distance relationship anywhere on the map.
https://maptools.com/tutorials/utm/why_use_utm

Why Use UTM Coordinates The UTM coordinate system offers the following benefits: A square grid UTM Provides a constant distance relationship anywhere on the map. In angular coordinate systems like latitude and longitude, the distance covered by a degree of longitude differs as you move towards the poles and only equals the distance covered by a degree of latitude at the equator. Since land navigation is done in a very small part of the world at any one time using large scale maps. The UTM system allows the coordinate numbering system to be tied directly to a distance measuring system. No negative numbers or East-West designators Grid values increase from left to right and bottom to top This is just like the X Y Cartesian coordinate system you learned high school math class. Simple Cartesian coordinate mathematics can be used. No spherical trigonometry is required! Coordinates are decimal based Ones, tens, hundreds and so on. No more minutes and seconds to convert. Coordinates are measured in metric units All UTM coordinates are measured in meters. Most of the world has already adopted the metric system. Now you won't need to remember how many feet are in a mile. And what's that in yards?

## Knowledge Base

### Accuracy vs. Precision
https://maptools.com/learn/accuracy-vs-precision

What accuracy and precision are Two words that get used interchangeably in casual speech, but mean different things: Accuracy is how close a measurement is to the true value. Precision is the resolution or repeatability of the measurement — how finely the result is reported, and how reproducibly the same measurement device produces the same result. The two are independent. A coordinate written to one-meter precision can be 200 meters from the actual location (precise but inaccurate — common with the wrong map datum). A coordinate written to 100-meter precision can be exactly correct within that 100-meter square (accurate, less precise). And the worst combination — imprecise and inaccurate — looks no different on the page from the best one until you compare it against truth. The distinction is worth treating on its own because it's the conceptual frame for several rules in navigation practice — coordinate truncation, tool-precision matching, declination rounding, GPS EPE discipline. Those rules are easier to follow once you see that they're all variations of the same idea: match what you write to what you actually measured. The classic illustration A dartboard. Four hypothetical shooters, each throwing five darts: Pattern Accuracy Precision Five darts in a tight cluster on the bullseye High High Five darts in a tight cluster, all near the upper-left corner of the board Low High Five darts scattered around the bullseye, no one of them close High (on average) Low Five darts scattered around the upper-left corner of the board Low Low The high-precision-low-accuracy case is the dangerous one in navigation. The tight cluster looks confident. It's wrong by a known offset that no amount of additional measurement with the same equipment will reveal. The classic example: a GPS reading positions to 1-meter precision while configured for the wrong map datum — the answers are tightly grouped and consistently wrong by about 200 meters. That's not a rounding problem; that's a systematic accuracy problem masquerading as confidence. Precision is set by the measurement floor — not by the printed marks Every measurement has a precision floor: the finest distinction you can honestly make with this tool, on this medium, under these conditions. Reading a result past that floor doesn't add information — it adds the appearance of information. The common shortcut is to equate the floor with the tool's finest graduation. That's wrong in both directions, and it's worth getting right — it's the difference between under-using a good tool and over-trusting a number. You can read between the marks. Interpolating a reading to a fraction of the smallest graduation is normal, expected practice — not a cheat. The working convention is that a careful eye resolves about one-tenth of a division under good conditions, or conservatively one-half when the read is coarse or the instrument is jittery. This is exactly why MapTools grid tools print a dot in the center of each 100-meter cell: the dot is an interpolation aid — a built-in halfway reference so you can estimate position within the cell instead of only naming which cell you're in. A tool's graduations are a floor on what it labels, not a ceiling on what you can read. But the real floor is set by whatever gives out first — and it usually isn't the graduation: The medium. On a 1:24,000 map, 100 meters is 4.2 mm of paper and 10 meters is 0.42 mm. Interpolating a 100-meter grid down to ~10 meters means splitting that 4.2 mm by eye, with the center dot halving the span you're judging — squarely doable. Going finer is not: 1 meter is 0.042 mm, below the width of the printed line, and the paper itself expands and contracts with humidity. About 10 meters is the practical floor on a 1:24,000 paper map, regardless of what any tool's marks claim. See Map Scale for the ratio that drives this. The fix for needing finer precision is a finer-scale map — not a finer tool or a steadier hand. Instrument repeatability. A compass dial graduated every 2° can honestly be interpolated to 1°, and a sighting or mirror compass marked in 1° to about ½° — because the instrument is steady enough to support it. What stops you going finer on a baseplate compass usually isn't the dial spacing; it's the needle's settling oscillation (a degree or two) and how steadily you hold the capsule. The better-mounted instrument earns the finer read. The marks aren't the limit; the repeatability is. Systematic accuracy. Even a legitimate interpolated read hits a wall where extra precision stops buying accuracy. The National Map Accuracy Standard puts a 1:24,000 map's own horizontal error at about ±12 meters. So a clean 10-meter interpolated position is already brushing the map's own registration error — read "to the meter" and you'd be reporting a precision the map itself can't back. This is the accuracy-vs-precision distinction biting in the field: you can refine the reading past the point where the map is true. So the honest grid-tool statement has two cases, not one: Read to the nearest cell, a 100-meter grid tool gives 100-meter precision — the abbreviated coordinate names the cell, and the 10- and 1-meter digits are genuinely absent. Read with interpolation (using the center dot), the same tool gives roughly 10-meter precision — a real, honestly-estimated 10-meter digit. It does not give you a 1-meter digit; the paper gave out first. And the GPS, as always, is its own case: A GPS reports coordinates to 1-meter precision by convention. The actual accuracy is usually 5–20 meters depending on conditions — see the GPS EPE section below. The 1-meter digits on the display are precision; the 5–20-meter ground reality is accuracy. Interpolating is not inventing. The two look alike on the page and are opposites in practice. Interpolating to a 10-meter read and writing that 10-meter digit records something you actually estimated, within the tool's and the medium's floor. Inventing the 1-meter digit — writing 559734 when you read 559.7 and the paper can't resolve finer — fabricates a digit you never saw. The truncate-don't-round discipline below polices the second; it has no quarrel with the first. How that precision gets reported in a coordinate depends on the format — and the formats fall into two camps. How coordinate formats express precision Coordinate formats fall into two camps in how they handle precision: Lat/lon coordinates name points. A latitude/longitude pair identifies a specific point on the Earth; precision is set by how many digits you write past the smallest unit. UTM, MGRS, and USNG coordinates name squares. A truncated coordinate identifies a square on the ground rather than a point. The square's size is set by how many digits you write, and the coordinate refers to the SW corner of that square. The two camps handle the "report only what you measured" rule differently. UTM, MGRS, and USNG: drop or pad the unmeasured digits Abbreviated MGRS / USNG lets you literally drop the unmeasured digits. A 100-meter grid-tool reading becomes a six-digit abbreviated coordinate (597 372); a 10-meter reading becomes eight digits (5974 3722). The number of digits is the precision claim. Full UTM, written in meters, has no such freedom — the easting and northing are always integers to the meter. A 100-meter measurement gets written as 0559700 4137200, with the trailing zeros as a positional placeholder. This is a convention, not a lie: an experienced reader treats 0559700 as either "exactly on the 100-meter line" or "measured to 100 meters and zero-padded," and uses context to tell which. But the ambiguity is real, and it's one of the places where the UTM convention is awkward. What not to do: invent the 10-meter and 1-meter digits to "fill in" the coordinate. Writing 0559734 4137268 when you actually measured 559.7 and 4137.2 overstates precision by a factor of ten and silently misleads anyone who acts on the number. Lat/lon: precision is set by digit count Lat/lon coordinates name points, not squares. Precision is set by how many digits you write past the smallest unit, and the format choice — DMS, DDM, DD — is a notation choice, not a precision choice. Any of the three lat/lon formats can express any precision; you just have to use enough digits. DD reads as more precise at a glance because the digit-count arithmetic is more visible — decimal degrees are base-10, while DMS hides precision behind a mixed-base notation (60 minutes per degree, 60 seconds per minute). The appearance is misleading: the same point can be expressed at the same precision in any of the three notations. DMS (hddd° mm′ ss″) — latitude: Resolution Metric Imperial 1° ~111 km ~69 mi 1′ ~1.85 km ~1.15 mi 1″ ~31 m ~101 ft 0.1″ ~3.1 m ~10 ft 0.01″ ~31 cm ~12 in DDM (hddd° mm.mmm′) — latitude: Resolution Metric Imperial 1′ ~1.85 km ~1.15 mi 0.1′ ~185 m ~607 ft 0.01′ ~18.5 m ~61 ft 0.001′ ~1.85 m ~6 ft 0.0001′ ~18.5 cm ~7 in DD (hddd.ddddd°) — latitude: Resolution Metric Imperial 0.1° ~11 km ~7 mi 0.01° ~1.1 km ~0.7 mi 0.001° ~111 m ~365 ft 0.0001° ~11 m ~36 ft 0.00001° ~1.1 m ~3.6 ft 37° 25′ 30.0″ N, 37° 25.500′ N, and 37.42500° N all describe the same point to roughly 1-meter precision. The notation differs; the precision doesn't. Latitude vs. longitude. The ground distances above are for latitude — 1° of latitude is about 111 km / 69 mi anywhere on Earth. Longitude distances vary with latitude. A degree of longitude is the same ~111 km / ~69 mi at the equator, shrinks to about 96 km / 60 mi at 30° N (south Texas, north Florida), drops to about 79 km / 49 mi at 45° N (Oregon, Maine, Minnesota), and continues shrinking toward zero at the poles. In CONUS, expect longitude distances at any given precision to be roughly two-thirds to nine-tenths of the latitude values in the tables. UTM doesn't have this asymmetry — a UTM meter is a meter everywhere, which is one of the practical reasons to prefer UTM for land navigation. The underlying discipline is the same in all formats: write what you measured, in the format's idiom, and don't make up the digits you didn't. Truncate, don't round When you abbreviate a coordinate to a coarser precision, truncate the extra digits — do not round them. Worked example (from the MGRS / USNG abbreviation rules): An easting of 0559751 becomes 597 at 100-meter precision, not 598. The reason: the truncated coordinate names the grid square the point is in. Truncating to 597 says "somewhere in the 597-XXX 100-meter square." That square actually contains the point. Rounding to 598 would name a different square — the one to the east — that doesn't contain the point. Rounding silently moves your position by up to 100 meters in the wrong direction. The general form of the rule: as precision decreases, the square gets bigger; the reported coordinate names the square the point is in, not the nearest grid intersection. By convention, the coordinate names the square by its SW corner — the corner with the easting and northing values produced by the truncation. The FGDC USNG standard formalizes this with a precision ladder (using the same example easting/northing): Coordinate form Square size 18SUJ20 10 km 18SUJ2306 1 km 18SUJ234064 100 m 18SUJ23480647 10 m 18SUJ2348306479 1 m Each level adds two digits — one to the easting, one to the northing — and shrinks the square by a factor of ten. Both halves of the coordinate carry the same precision. A coordinate with three easting digits and four northing digits isn't precise; it's malformed. Match precision to the need, not to what's available The other direction of the rule: don't over-measure when the application doesn't require it. From the declination correction worked example: a calculated declination of 15° 27′ is a perfectly precise number, but most field navigation only needs the nearest half-degree or full degree. The honest field answer is "15½°" — or "15°" if the route doesn't require even that. Carrying the 27′ through a chain of mental arithmetic adds work and adds opportunities for error, while delivering a precision the next step in the workflow doesn't use. A general principle worth stating directly: the right precision is the coarsest one that supports the decision you're using the number for. A backcountry hiker plotting an attack point doesn't need 1-meter accuracy. A search-and-rescue team coordinating a sweep does. A surveyor establishing a property corner needs more than either. Calibrate the precision to the use. The general field practice for civilian land navigation, per the FGDC USNG standard, is 100-meter or 10-meter precision for "general field applications." Anything finer is "special applications" and should be justified by what the work requires. GPS EPE — the honest precision number A modern handheld GPS displays coordinates to 1-meter precision, but its actual accuracy varies with satellite geometry, atmosphere, terrain, and tree cover. Most receivers expose this as an Estimated Position Error (EPE) field — the receiver's own estimate of how far off the displayed position might be. Get in the habit of checking EPE every time you read a position. Typical values: Under good conditions (open sky, multiple satellites high above the horizon): EPE under 10 meters is common. Acceptable (light tree cover, moderate terrain): EPE under 20 meters / 60 feet. Suspect (canyon, dense canopy, hand inside a pack): EPE may climb to 30 m or more — the reported position is still precise to 1 meter on the display, but inaccurate enough that those last digits are meaningless. The EPE habit is the operational form of the accuracy-vs-precision discipline: the GPS shows you a precise-looking number, the EPE tells you how much of that precision to trust. See GPS Setup for Map Coordinates for receiver configuration that puts EPE on a screen you actually look at. Where this concept shows up in practice A short tour, so the rule is recognizable when you encounter it: UTM / MGRS / USNG — the truncate-don't-round rule; the precision-by-digit-count ladder. Map Scale — the rule that the tool's marked precision must match the map's scale; the practical 10-meter limit on a 1:24,000 paper map. North References (True, Magnetic, Grid) and Declination — the "you probably don't need more than half a degree" guidance for declination correction. GPS Setup for Map Coordinates — the EPE field as a routine check; matching coordinate format precision (1 m, 10 m, 100 m) to use case. Map Datums — the failure mode where precise coordinates are accurate to the wrong datum and consistently offset by a known amount. All of these are the same idea wearing different clothes: a number is only as good as what produced it, and writing extra digits doesn't make it better. When to truncate — and when to write the displayed digits The truncation discipline above is right for some measurements and wrong for others. Two situations look similar but call for different practices. Map measurements with a precision tool: truncate to what you measured When you read a coordinate off a map with a grid tool, slot tool, or ruler, the tool sets your precision. Write the coordinate to match: drop the unmeasured digits in abbreviated MGRS/USNG, zero-pad in full UTM. Don't invent digits the tool didn't give you. A coordinate written with more precision than the producing tool measured lies about what is known. A reader who sees 10S 0559751 4137247 and knows it came from a map measurement reasonably interprets it as a 1-meter position. If the tool actually measured to 100 meters and the trailing 51 / 47 are invented, the reader has been misled — they may pace the last 50 meters expecting to land on a feature, when the original measurement put the feature anywhere within a 100-meter square. The honest form of "I measured to 100 meters" depends on the format: In abbreviated MGRS/USNG, drop the digits you didn't measure: 597 372. The reader sees a six-digit coordinate and knows it's a 100-meter square. In full UTM in meters, write the coordinate with trailing zeros where the measurement ran out: 10S 0559700 4137200. The reader has to read the convention — "ends in 00 00" usually means "measured to 100 m" — but the format doesn't allow anything cleaner. GPS readings: write all the digits the receiver shows GPS is the practical exception. A modern handheld displays coordinates to 1-meter precision, but actual accuracy is typically 5–20 meters and depends on satellite geometry, terrain, and tree cover. Everyone who works with GPS data knows this; the EPE field gives the per-reading specifics. In the field, just write down what the GPS shows. Three reasons: The over-precision is well-understood — the next person seeing your 10S 0559751 4137247 will apply GPS-reading judgment (and EPE limits) rather than treating it as a survey-grade position. The full digits preserve information. You can always truncate later; you can't recover digits you didn't write down. A truncation blunder is harder to recover from than over-precision. Writing the wrong digits because you tried to round or truncate in your head (597 372 when the measurement was 5975 3725) silently moves the point. Writing all the displayed digits preserves the original observation, even when it implies more precision than is physically real. The principle still holds — don't invent digits a tool didn't give you — but for GPS, the displayed digits are what the tool gave you, even if the underlying accuracy is coarser. The honest record is the receiver's output; the interpretation of that output requires knowing the tool produced it. Common misconceptions

### Choosing a Coordinate System
https://maptools.com/learn/choosing-a-coordinate-system

Which coordinate system should you use? Most GPS receivers come out of the box set to lat/lon, and many people never change it — they don't realize there's a choice, or that another system might suit them better. There is a choice, and for most land navigation I'd steer you toward a UTM-based system. UTM, USNG, and MGRS are all built on the same square-grid foundation; they're easy to plot, easy to measure, and the numbers translate directly to distance on the ground. Lat/lon still wins in a few situations — very small-scale maps, and any work where your peers are already using it. This page is about making that choice deliberately instead of by default. The four systems worth knowing about, all of which work with MapTools plotting tools: Lat/lon — the global angular system (degrees of latitude and longitude). Universal, but awkward to measure with and easy to fumble the minutes-and-seconds arithmetic. UTM — Universal Transverse Mercator. A metric, square-grid system. The workhorse for land navigation. USNG — United States National Grid. UTM's grid with a letter-based labeling scheme, designed for civilian and emergency use in the U.S. MGRS — Military Grid Reference System. Essentially the same grid and labeling as USNG, used by the military. A useful framing: USNG and MGRS are ways of writing down a position on the UTM grid. If you learn UTM, you've already learned most of what you need for the other two. All MapTools tools that work with UTM also work with USNG and MGRS. Three questions that settle the choice Use the same system your peers use If you're passing coordinates back and forth with other people — a search team, a hunting party, a class — use whatever they use. A coordinate is only useful if the person receiving it can plot it without translating it first. Most aviation and maritime users are already on lat/lon, so if you're coordinating with pilots or boaters, lat/lon is the practical answer regardless of what you'd prefer on land. Military work is usually MGRS. Match the room. Use a system that works with your maps Map scale drives this one: On large-scale maps (a USGS 1:24,000 topo, most hiking maps), a UTM-based system is usually the better choice. Many of these maps already carry a UTM grid, and where they don't you can add one. USGS prints both lat/lon and UTM references on its large-scale maps. On small-scale maps — anything covering more than about 6° of longitude, or 1:1,000,000 and smaller — prefer lat/lon. UTM grids on small-scale maps stop being square (the projection has to keep lines of longitude looking parallel), which defeats the main advantage of UTM. A caution about lat/lon references on maps: some mapmakers print "decorative" lat/lon marks that are approximate at best. Before GPS, almost nobody checked them. Many maps still haven't caught up. Verify before you trust. Use a system that's easy to use When the first two questions don't decide it for you — you've got a large-scale map, you have UTM information, and nobody's forced your hand — UTM is usually the easiest system to actually work with in the field. Its advantages: Square grids. East-west units are the same as north-south units. Decimal-based: no fussing with minutes and seconds. Coordinates translate directly to distances on the ground. Precision is intuitive — you don't have to wonder how far a tenth of a second of longitude is. Easy to abbreviate when you're working in a small area. When lat/lon is still the right call Don't read "UTM for land navigation" as "lat/lon is obsolete." Reach for lat/lon when: Your map is small-scale (continental, marine charts, world maps). You're working with aviation or maritime people. A coordinate arrives in lat/lon and you just need to plot it once — convert it or plot it as-is rather than reworking your whole setup. The Map Datums still matters in every system. Whatever notation you pick, the datum is the Earth-model the numbers are measured against, and it has to match between your map and your GPS. More on maptools.com Selecting a Geographic Coordinate System — the full comparison this page is drawn from, with links to the per-system quick guides for UTM, MGRS, USNG, and lat/lon. How to teach it

### Compass Bearings
https://maptools.com/learn/compass-bearings

What a bearing is A bearing is a horizontal angle measured from a north reference line, in a clockwise direction, to a point of interest some distance away from the point of measurement. North is 0°, east is 90°, south is 180°, west is 270°. A bearing alone defines a line — to fix a location you also need a distance, a second bearing from a different point, or an intersection with a known feature on the map (a road, a stream, a contour line). A bearing has to be referenced to a north — true, magnetic, or grid. See North References (True, Magnetic, Grid) and Declination for the geometry. The discipline that catches more downstream errors than any single other habit: always write the north reference next to the angle. "45°" is meaningless. "45° magnetic" is unambiguous. What bearings are for Three uses: "Where am I?" (Resection.) Take bearings to known visible landmarks; plot them on the map; you're at the intersection. With only one visible landmark, you can still fix your position by intersecting a single back bearing with a known linear feature you're on (road, trail, ridgeline, stream) — you're where the back bearing crosses the feature on the map. Useful when you can see the landscape but aren't sure where on the trail you are. "Where is that?" (Intersection.) From two or more known points, take bearings to a distant unknown object — smoke from a fire, a cave entrance across a lake, a person waving from a ridge. Plot the bearings; the target is at the intersection. Route planning. Plot a sequence of bearing-and-distance legs through the terrain you'll cover. Walk the bearings in the field. Sighting a bearing in the field Taking a bearing means measuring the direction from where you're standing to a target — a peak, a tower, a feature you can identify on the map. The technique: Hold the compass level. Gravity affects the needle's free movement. A tilted compass gives a tilted reading. Aim the compass at the target. The mechanics differ between a plain baseplate and a mirror compass: Plain baseplate. Hold the compass flat at waist level. Rotate your whole body until the long edge of the baseplate (or the direction-of-travel arrow) points at the target. Your eye alternates between the target ahead and the compass below — practice keeping the line straight across the alternation. Mirror compass. Open the lid to about 45°. Hold the compass at eye level and sight through the notch in the lid at the target. The mirror reflects the bezel and needle into your sight line so you can read them without breaking your sight on the target. This setup gives noticeably tighter accuracy than the plain baseplate technique. Rotate the bezel until the orienting arrow boxes the magnetic needle — the needle parallel to the sides of the orienting arrow, with its north end at the north end. On a mirror compass, you do this while still sighting the target through the lid; on a plain baseplate, take your eye off the target to set the bezel, then re-sight to confirm the aim hasn't drifted. Read the bezel at the index line. Write the bearing down with its north reference (45° magnetic, not just 45°). Distant targets sight more accurately than nearby ones. A small angular error on a faraway peak translates to a small ground error; the same angular error on a nearby tree can move the bearing line by tens of feet at distance. Pick targets that are identifiable on the map and visible from where you stand: named peaks, distinctive saddles, towers, road bends. A baseplate compass without a mirror is reliably good to about ±2°. A mirror compass to about ±1° with care. Beyond that, sighting noise from needle oscillation and eye-compass alignment dominates — don't over-state field-sighted bearings beyond what the tool actually delivers. See Accuracy vs. Precision for the underlying principle. A correctly-sighted compass will still mislead you if there's ferrous metal close to it. A pen with a metal clip in your hand, a metal pocket knife on your belt, a phone in a chest pocket, or a watch with a steel back can deflect the needle by a few degrees with no visible warning. Before taking a critical bearing, check what's within a foot of the compass. See Compass Uses under Magnetic interference for the full catalog of common-culprit objects. Following a heading Following a heading means walking in a chosen direction over the ground — most commonly along a route segment planned on the map. The compass gives you the direction; visible landmarks let you stay on the line. Set the heading and establish landmarks Set the desired heading on the compass bezel — magnetic if the compass is un-adjusted, grid or true if it's declination-adjusted. With the compass held level at eye level: Rotate yourself (not the bezel) until the orienting arrow boxes the magnetic needle. Your body is now facing the heading direction. Pick a forward landmark on the heading line — a tree, a rock outcrop, something far enough ahead that walking to it will take some time. Establish a back landmark. Without changing the bezel and without doing any arithmetic, align the SOUTH end of the magnetic needle with the orienting arrow's north — i.e., put the south end where you'd normally put the north end. The same bezel setting now reads the reverse heading; the compass is pointed back along your line. Pick a back landmark on this reverse sight — a feature you started from or just passed. Walk to the forward landmark without staring at the compass. The two landmarks keep you on the line. When you reach the forward landmark, re-sight a new forward landmark on the same heading and walk to it. The pattern is landmark-to-landmark, not bezel-staring. Use both sights to stay on the line The forward landmark keeps you walking the right direction. The back landmark lets you confirm you've stayed on the line as you've walked. Periodically check both: Forward sight: north end of the needle in the orienting arrow, lined up with the forward landmark. Back sight: south end of the needle in the orienting arrow, lined up with the back landmark. When both line up, you're on the original heading line. If one is drifting, you've drifted off — correct your walk to bring both back into alignment. The two-landmark back-sight is the most reliable way to follow a heading across terrain. It costs no extra bezel manipulation and no arithmetic, and it gives positive confirmation that you're still on the line rather than open-loop "I think I'm still heading the right way." Forward bearings vs. back bearings More generally, a back bearing (also called a reciprocal bearing) is the exact reverse of any bearing — 180° in the opposite direction, the same line of sight pointed the other way. If a forward bearing reads 045°, its back bearing is 225°; if 200°, its back bearing is 020°. Whether you call a given bearing "forward" or "back" depends on which endpoint you're standing at when you sight it: Forward bearing. Sighted from a known location to an unknown location. You're at a known point on the map; you sight to a target you want to locate (a column of smoke, a person on a distant ridge). Plotted on the map starting at your known point, drawn in the bearing's direction. The natural case — "where is that?" Back bearing. Sighted from an unknown location to a known location. You're at an unknown point on the ground; you sight to a landmark you can identify on the map. To use the bearing on the map, the line needs to start at the landmark and extend backward through it toward your unknown position. The plotting move for a back bearing — without any arithmetic — is to plot it on the map as if it were a forward bearing from the known landmark, then extend the same line backward through the landmark. Your position is somewhere along that backward extension. Procedure: Treat the measured bearing as a forward bearing from the known landmark. Plot it at the landmark with your normal tool, drawn in the bearing's direction. Extend the same line backward through the landmark. That backward extension points to your unknown position. No ±180° calculation needed. Two or more back bearings from different landmarks produce a resection — the intersection of the backward extensions is your location. Plotting tools Three baseplate-style tools, plus a brief note on the lensatic compass: Protractor The simplest tool: no moving parts and conceptually transparent. A clear plastic protractor with a center hole, marked in degrees clockwise from a north arrow. Procedure (with a sighted bearing of, say, 60° magnetic, plotting toward an unknown position from a known landmark): Convert the bearing to grid (or whatever north reference your map uses). If the local declination is 5° E, magnetic 60° = grid 65°. (See North References (True, Magnetic, Grid) and Declination for the formula.) Center the protractor on the known point on the map. Rotate the protractor so its north arrow aligns with the map's Grid North reference lines. Mark the map at the desired bearing along the protractor's edge. Use a straight edge to extend the bearing line through the marked point. (Sewing thread or dental floss strung through the center hole works well for long lines.) A useful sanity check before starting: identify the rough cardinal direction (N, NE, E, SE, S, SW, W, NW) the target should be in. If your plotted line points 80° away from that rough direction, you've made a mistake. Baseplate compass (unadjusted) A baseplate compass with no declination correction set on the bezel. The compass functions as both a sighted bearing-taker and a plotting protractor. Procedure to plot a sighted bearing: Convert to grid. The compass is reading magnetic; the map is referenced to grid. For a 60° magnetic bearing with 5° E declination: add 5°, plot 65° grid. Set the converted bearing on the compass bezel. Place the compass's edge at the known point on the map. Align the compass capsule's orienting lines with the map's north reference lines — not with the magnetic needle. The magnetic needle is irrelevant during plotting and may point in any direction. Draw the bearing line along the compass edge. Baseplate compass (declination-adjusted) A baseplate compass with the declination angle pre-set on the bezel. The compass reads grid (or true) directly, no field conversion required. Since we adjusted our compass to read directly relative to Grid North, no adjustment needs to be made to our bearing. Same procedure as the unadjusted compass, minus the conversion step. Faster in the field, but the compass must be re-set when local declination is different. Whenever you move to an area where the declination differs, you'll need to readjust. The same warning applies: the magnetic needle is not used during plotting and may point in any direction. Lensatic compass Lensatic compasses use a sighting and plotting procedure substantially different from baseplate-style technique. They have a significant user base, particularly in military contexts where the lensatic is the standard-issue tool. The procedure isn't covered here; lensatic users will want lensatic-specific instructions. More bearings, smaller error A single bearing gives you a line. Two bearings give you an intersection — but compass and plotting errors mean two "intersecting" bearings rarely meet at a single mathematical point. Three bearings tell you something about the size of your error. The geometry of the landmarks matters as much as the precision of the bearings. Two bearings that cross at nearly right angles produce a sharp intersection; two bearings meeting at a shallow angle (close to 0° or 180° apart) produce a vague one — the same bearing error translates to a much larger position offset. Pick landmarks spread widely in azimuth: roughly 60°–120° apart for a two-landmark resection, ~120° spacing for three. Two landmarks in nearly the same direction give a poor fix; two landmarks separated by close to 180° (one ahead, one directly behind) are worse — the back bearings overlap as a single line with no useful intersection at all. The same principle applies to intersection (pick base points so the target subtends ~90° at the bearing crossing) and to the single-bearing-plus-linear-feature case (the bearing should cross the feature as close to perpendicular as possible). The smaller the triangle, the smaller the errors. Plotting a third bearing produces a small triangle (the triangle of uncertainty) bounding your true position. If the triangle is larger than expected, the four likely culprits are: Sighting error when taking the bearing (most common). Map plotting error when drawing the bearing line. Misidentification of the landmark — you took a bearing to one peak but plotted from another. Map vs. terrain mismatch — old map with shifted shorelines, washed-out roads, etc. A third bearing usually identifies which: if it forms a tight triangle with the other two, you've got measurement noise. If it's wildly off, you misidentified something. When the triangle is small enough to work with and you need to commit to a single point, pick the most likely position from terrain context — for instance, if the bearings intersect just off a mapped shoreline, the shoreline is more likely the true position than a point sitting in open water. Reading conventions Three digits, spoken. Over the radio, read bearings as separate digits with leading zeros for values under 100° — "zero-four-five degrees magnetic," not "forty-five magnetic." Not universally followed, but worth the discipline: radio noise turns "forty-five" into "forty-something" more readily than it garbles "zero-four-five." Always include the north reference. 45° magnetic, 45° grid, 45° true. Don't make people guess. Bearings are always clockwise from north. Counterclockwise conventions exist in math but not in field navigation. "Heading," "bearing," and "azimuth" are used interchangeably in most contexts; aviation and marine have stricter distinctions that don't matter for land nav. Further reading on maptools.com Plotting a Bearing — tutorial overview Using a Protractor — protractor-based plotting Using a Compass to Plot — plotting with a compass as protractor Compass and Declination — adjusting for declination when plotting Bearings to Locate a Target — using bearings to find an unknown point More Bearings to Confirm Location — multi-bearing fixes Common student misconceptions

### Compass Uses
https://maptools.com/learn/compass-use

What a compass is used for In wilderness navigation, a compass is used to do five things: General orientation to the four cardinal directions — which way is north, south, east, and west. Orienting a map to north — rotating the map so the directions on the paper line up with the directions on the ground. Traveling along a heading — walking in a chosen compass direction, either to maintain a general direction of travel or to follow a precise bearing. Finding the location of an unknown thing — sighting bearings to it from two or more known positions, then plotting those bearings on the map (intersection). Finding your own location — sighting bearings to known landmarks from where you stand, then plotting the back-bearings on the map (resection). Each of these uses is real. Each one also has limits, and several of them are routinely overestimated. A compass is one tool among several. For some uses, almost any compass — including a $5 zipper-pull — is enough. For others, you need a real baseplate compass and practiced skill, and even then another tool often does the job better. In particular, for the "where am I?" question, a GPS is faster, easier, more reliable, and more accurate than a sighted-and-plotted compass bearing. That position runs against decades of land-navigation training tradition, much of which persists because that's how it was taught, not because it's still the best method available today. What the compass is not is a piece of safety gear that protects you by being in your pocket. Carrying a compass without the skill to use it doesn't make you less likely to be lost. What actually keeps you found is a map, the ability to read it, awareness of the terrain around you, and — for fixing your position — a GPS. Where the compass does come into its own is in conditions where the visible landmarks navigation usually relies on disappear: fog, whiteout, dense forest, night travel. In those conditions traveling along a heading goes from optional to essential, and the compass — paired with the skill to use it — goes from extra weight to load-bearing gear. The compass earns its place in specific, named uses; what follows is what those uses are and where they end. To watch these techniques done rather than described, the MapTools compass video series at https://maptools.com/videos/compass covers the parts of a compass, measuring angles, sighting a bearing, and the north references — start there if the question is how do I physically do this with a compass and a topo map. Orientation to the cardinal directions The compass tells you which way is north — and from there, which way is south, east, and west. Most of the time, you can get this right without a compass. The sun, the time of day, prevailing wind, knowledge of which mountains lie which way, and the situational awareness you've built up walking in — all give you enough to know which way is north. The compass adds little once you're actually paying attention to your surroundings. This is the same principle the next section uses for the simplest approach to orienting the map — just applied to your own awareness rather than to the paper. In one direction you rotate the map to match the world; in the other you rotate your sense of direction to match what the compass tells you. The skill is the same and the situations that call for it are the same. A simple, low-cost compass is good enough for this use — a zipper-pull or button compass is plenty. Orienting your map to north Orienting the map means rotating it so the directions on the paper line up with the directions in front of you — the north edge of the map points to actual north, the road that runs east on the map runs east in your field of view. There are three approaches to orienting the map, each more accurate and more effortful than the last. Cardinal awareness and visible terrain Use your awareness of the cardinal directions, combined with visible terrain features. Rotate the map until features on the paper point in the same direction as those features in front of you. The least accurate of the three, but often more than adequate. Fast and easy. No compass needed at all. The limits are visibility and feature recognition: in dense cover, fog, or featureless terrain, this method doesn't work — which is the situation the next two approaches exist for. Align the needle with the magnetic-north arrow Place a compass on the map near the magnetic-north arrow of the map's declination diagram. Rotate the map and compass together until the compass needle points in the same direction as that arrow. More accurate than the previous approach, and more difficult. The arrow must be the magnetic-north arrow, not the true-north or grid-north arrow — see North References (True, Magnetic, Grid) and Declination for the geometry. Line up with the wrong arrow and the map ends up off by the local declination, which can be tens of degrees. Set the compass to account for declination Set the compass to account for the magnetic declination, either by dialing it in on the bezel directly or by using the compass's declination adjustment. Align the orienting lines on the baseplate with the true-north (or grid-north) lines on the map, and rotate the map and compass together until the magnetic needle is boxed in the orienting arrow. The most accurate of the three methods, but somewhat tedious and error-prone. Accuracy at this level is seldom required for orienting the map. The mechanics here — declination adjustment, baseplate orienting lines, boxing the magnetic needle — are shared with bearing work, which is why the technique often gets taught alongside bearings. But accurately orienting the map is not a prerequisite for taking or plotting bearings with a baseplate or protractor compass; the two are independent operations. See North References (True, Magnetic, Grid) and Declination for the underlying geometry. Traveling along a heading The compass is used for travel in two distinct ways. They share mechanics — you're using the compass to keep yourself pointed in a chosen direction — but they're applied to different problems and tolerate very different amounts of error. Traveling in a general direction Use the compass to keep yourself walking in roughly the right direction. Doesn't require much accuracy. The compass's job here is to prevent the slow drift into wandering or walking in circles that happens when you're following no fixed reference at all. The compass is particularly useful for this at night and in poor visibility, when the terrain features and sun cues that would normally keep you oriented disappear. Any compass works for this — a zipper-pull is enough. Traveling along a specific heading Use the compass to walk a precise compass direction, like 48° M, often as part of a route plotted from the map. Before reaching for this use, be clear about what it costs. Straight-line travel on land is rarely the best route between two points — often it's an exceedingly difficult one. For most route-finding decisions, straight-line bearing-following should not be high on the list of options. See Route Planning and Following for the alternatives that almost always do better. Where specific-heading travel does earn its place: routes designed to avoid specific hazards on either side of the line, typically combined with night travel or poor visibility. Even in these cases, a preprogrammed GPS route is usually a better option: a GPS receiver shows you when you're drifting off the route, while a compass heading only tells you which direction to walk — not whether you're still on it. Finding the location of an unknown thing You can see something — a feature in the landscape, a column of smoke, a person on a distant ridge — and you want to know where it is on the map. From two known positions, sight a bearing to the unknown thing. Plot both bearings on the map. The thing is at the intersection. This is intersection. This use case is uncommon in recreational outdoor travel but real in specialized work. For something already named on the map (a peak, a road junction, a labeled feature), you don't need bearings — you just look it up. The limits: You have to be at known positions yourself, or able to move to known positions between sightings. The unknown thing has to stay visible from both points (smoke drifts; people move). Bearings have to be measured and plotted against a consistent north reference. Misidentifying the landmark you're standing on is the most common failure mode — and silently produces a wildly wrong fix. Two bearings give you a point. Three or more produce a small triangle whose size tells you about your error. See Compass Bearings for the procedure and the triangle-of-uncertainty discussion. GPS doesn't directly help here: a GPS tells you where you are, not where a thing you can see is. For this specific use case, a compass and map are the right tools — provided you can be at known positions while the thing stays visible. Finding your own location You're not sure exactly where you are. You can see two or more landmarks that you can identify on the map. Sight a bearing to each landmark from where you stand. On the map, draw the back-bearing from each landmark — the line going in the opposite direction of the bearing, which passes through your position. You're where they cross. This is resection. This is the canonical "I'm lost, where am I?" use case. It's also the use case where another tool now does the job better. A GPS gives you your position directly — faster, more accurately, and without requiring visible landmarks. For the "where am I?" question on a working GPS, resection isn't the right answer; the GPS is. The limits: You need visible, identifiable landmarks. That rules out the conditions you most often need a position fix in: fog, dense cover, featureless terrain, night. You need to correctly identify each landmark on the map. Peak misidentification is the most common failure mode, and silently produces a wildly wrong fix. The identifiable landmarks should ideally all sit on the same map sheet that covers your position. A landmark on an adjacent sheet is workable but awkward — the bearing line has to be extended across the sheet boundary. Landmarks two or more sheets away are virtually unworkable in field conditions. Bearings have to be measured and plotted against a consistent north reference. The procedure requires real practice — sighting in the field, converting north references, plotting back-bearings — all working together under field conditions, often with cold hands and wind. Resection earns its place when a GPS isn't available or working and you have the map and the practiced skill to use it. Otherwise the GPS does this job better. The procedure (sighting, back-bearings, plotting, the triangle of uncertainty) lives on Compass Bearings. Magnetic interference Every compass operation assumes the needle points to Magnetic North. When it doesn't, the operation produces a wrong answer with no warning indicator. Interference comes from two sources. Things on or near you Anything ferrous or magnetic close to the compass will pull the needle. The common culprits: A phone in a chest pocket or held near the compass. A camera on a lanyard. Belt buckles, metal-cased pocket knives, watches with a steel back. Resting the compass on a vehicle hood, a metal gate, or a steel-framed table. A useful habit: when a bearing surprises you, before second-guessing the map, check what's within a foot of the compass. Things in the ground Local geology can deflect the needle from the regional declination. In most places the effect is small enough to ignore. In a few places it's large enough that the compass is rendered useless. Three of the better-known cases: Ramapo Mountains, northeastern New Jersey — iron ore deposits. Malpais lava flows near Grants, New Mexico, north of the Gila Wilderness. Kingston Harbor, Ontario — magnetite and ilmenite deposits produce 16.3° W to 15.5° E of anomalous declination over two kilometers. See North References (True, Magnetic, Grid) and Declination for the full list and the geometry of how anomalous declination is plotted and corrected. In unfamiliar terrain, a useful sanity check before relying on the compass: take a bearing between two map features whose true relative direction you can read from the map. If the compass agrees, you're fine. If it doesn't, you've learned something important about where you are. "I have a compass, so I'm safe" The notion that simply having a compass makes you less likely to get lost is a placebo — common, comforting, and wrong. The compass is a precision tool that rewards skill; carrying one without the skill to use it confers no real safety. What actually keeps you found is: A map you can read. Awareness of the terrain around you and where you've been on it. For the "where am I?" question specifically, a GPS. The compass earns its place in those named uses — most of which can be done with a very simple compass, and some of which (notably resection) are done better by another tool. Outside those specific uses, the compass in your pocket is comfort, not safety. How much compass do you actually need? Each named use has a different answer to "what's the simplest compass that can do this?" Use Minimum viable tool Cardinal orientation Zipper-pull or button compass Orienting the map (cardinal + terrain) No compass needed Orienting the map (needle on magnetic-north arrow) Any compass with a free needle; a zipper-pull is fine Orienting the map (declination-adjusted) Baseplate compass with a declination adjustment Traveling in a general direction Zipper-pull or button compass Traveling along a specific heading Baseplate compass Finding the location of an unknown thing (intersection) Mirrored baseplate compass Finding your own location (resection) Mirrored baseplate compass Most outdoor travel only needs the first few rows. If the only uses you actually rely on are cardinal orientation, the simpler approaches to orienting the map, and traveling in a general direction, a $5 zipper-pull is enough compass. The precision baseplate-with-mirror in your pack is mostly weight you're carrying for uses you don't actually do. The honest question: which of these uses do you actually rely on in practice? Not which uses you've been taught the technique for — which ones do you actually use when navigating? Further reading on maptools.com 21st Century Navigation Handouts (PDF) — printable reference handouts covering the modern compass-and-GPS workflow Compass video series — the compass parts, measuring angles, sighting a bearing, and the north references, demonstrated on camera Learn: Compass Uses — this material as a student-facing page Learn: Compass Bearings — taking, following, and plotting a bearing Common student misconceptions

### GPS for Land Navigation
https://maptools.com/learn/gps-for-land-navigation

What GPS does for a land navigator A handheld GPS receiver answers one question precisely: "what coordinate am I at right now?" Combined with the skill and knowledge to plot that coordinate and you have a fast and accurate way to answer the "Where am I on my map?" question. It works in the dark and other low visability situations where more traditional navigation techniques may be difficult or impossible. Everything else useful a recreational GPS does for a hiker — waypoints, tracks, routes, ETA estimates, distance-traveled — is built on top of that one capability. For land navigation specifically, that means: You can plot your position on a paper map. GPS gives you the coordinate; you walk it back to a point on a map. See UTM Coordinates and Latitude and Longitude for the two coordinate systems most receivers can output. You can mark places you want to remember. Trailheads, water sources, the spot you parked. Waypoints are the receiver's stored coordinates with names. You can navigate toward a stored coordinate. Type or import a destination's coordinates and the receiver shows you a bearing and distance to it. Doesn't pick the route — you still do that with the map and your eyes. You can leave a breadcrumb trail. Track logging records where you've been. Useful for retracing your steps and for telling the next group what the actual route looked like. What a GPS does not do: pick a walkable route, read the terrain, warn you when the map is wrong, or replace a working understanding of Map Reading. It's a tool that delivers a coordinate; you do the navigating. What every recreational GPS user needs to know Setup decisions matter before you start: Coordinate system. UTM, MGRS, USNG, or lat/lon. Pick the one that matches the printed grid on the map you're using. See GPS Setup for Map Coordinates for the full setup walkthrough. Map datum. WGS84 is the modern default; older maps and surveys may be NAD27. Mismatched datums offset coordinates by 100m+, which is exactly enough to put your plotted position in the wrong drainage. See Map Datums. Battery strategy. Spare batteries (lithium AA are the standard for hiking-grade receivers) and the habit of turning the unit off between fixes — that keeps a set lasting months. For the deeper coverage of these decisions, see the GPS Setup for Map Coordinates concept. Categories of GPS The main categories: Dedicated handhelds (Garmin eTrex, GPSMAP, Oregon families; similar from other brands). Built for hiking — long battery life, rugged, button-driven, readable in sun. The mainstream of recreational GPS for the last 20 years. Smartphone GPS apps. Use the phone's built-in GPS chip plus offline-cached topo maps. Excellent display, much weaker battery story, fragile in cold and wet. Increasingly capable; not yet a full replacement for a dedicated handheld in serious backcountry. GPS watches. Convenient, weak at coordinate-display tasks, useful for tracks and waypoints if you live in the watch ecosystem. Satellite messengers with GPS (Garmin inReach and similar). GPS plus two-way satellite messaging. Different design center — emergency communication first, navigation second. A smarthpone GPS app is a great low to zero cost way to learn to use a GPS. App quality varies widely, make sure the app you choose supports the coordinate format you want to use, the map datum your map uses, has the ability to create stored waypoints, and supports pre-loaded offline maps. A good smartphone GPS app is plenty of GPS capability for day hiking and easy weekend trips. It's also a good backup for a dedicated handheld GPS. When you are doing longer trips, or trips in challenging conditions, most people ask the question is "which dedicated handheld do I buy?" — see the buying-a-GPS guidance. Accuracy realities GPS accuracy in open terrain is around 3–10 meters with a modern receiver; under tree cover or near cliffs it degrades to 10–30 meters; in deep canyons or under heavy canopy it can degrade further or lose lock entirely. See GPS Accuracy for the detailed treatment. The practical implication: a GPS coordinate is a square, not a point. The reported precision (the digit count) often suggests more accuracy than the receiver actually has. A coordinate ending in ...832m E 683m N displayed to 1-meter precision is plausibly accurate to ~10 meters — useful, but not "this exact rock." When the GPS dies There are three primary failure modes. The user forgot how to use the GPS or has it set up incorrectly. The GPS receiver runs out of batteries or has some other sort of failure. The GPS system itself is being tampered with or has been turned off. The first one is on you. You need to know how to use your tools. The second one is less of an issue as the cost of GPS receivers drops. A hiking party is now likely to have several GPS receivers between them. Especially when you include the smartphones and GPS enabled watches. The third one is becoming more common in parts of the world with active military combat. There are alsoa few unlikely scenarios where large swaths of the globe could loose GPS coverage. That's the case for a fallback — not a reason to distrust the GPS. Rely on it as your primary tool, and keep the underlying Map Reading skill (plus a backup device or a paper map) so a failure is a detour, not a crisis. This is also why it's worth building your Map Reading and Compass Bearings skills along with your GPS skills. Your car could quit working. That's not a good reason not to rely on a car for transportation. But it is a good reason to not forget how to walk. How GPS works (briefly) You don't need this to use a receiver, but it's where the accuracy — and the failure modes — come from. The system is a constellation of about 24 satellites in six orbital planes, arranged so at least four are above the horizon anywhere on Earth, any time of day. Each satellite carries an atomic clock and continuously broadcasts a coded signal stamped with the exact time it was sent. Your receiver measures how long each signal took to arrive and multiplies by the speed of light to get its distance to that satellite. One distance puts you somewhere on a sphere around the satellite; a second and third narrow that to a small "error triangle"; and a fourth both pins down the position and corrects your receiver's cheap clock — the satellites' clocks are exact, yours isn't, but its error is the same for every measurement, so four satellites let the receiver solve for it. Because each satellite also broadcasts its own precise orbital position (monitored and corrected daily by ground stations), the receiver can then compute where you are. Two things worth carrying into the field: You need a clear line to at least four satellites. Canyon walls, dense wet canopy, or a metal roof block signals and weaken or prevent a fix. Satellite geometry matters. Satellites bunched in one patch of sky give a weaker fix than ones spread across it — which is why the receiver reports an estimated error (EPE), not just a position. See the How the GPS System Works slides below for the diagrams. Where coordinates come from when you don't have a GPS A map with a printed grid is itself a coordinate source. You can read a UTM or lat/lon coordinate off the map by eye or with a measuring tool, and report your position to a partner who has a GPS. See UTM Coordinates for the reading-from-map technique. Both directions matter — map → coordinate and coordinate → map — because navigating successfully often requires bouncing between the two.

### GPS Setup for Map Coordinates
https://maptools.com/learn/gps-setup

What GPS setup is for A modern handheld GPS, out of the box, will tell you where you are — but in a format and against a reference that may not match the map you're carrying. GPS setup is the small handful of configuration choices that make the receiver and the map agree, so the position the GPS reports can be plotted directly on the paper map without conversion or correction. The two settings that matter most are: Position format — the format the GPS uses to display your coordinates (UTM, MGRS, USNG, or one of several latitude/longitude variants). Map datum — the geodetic reference the GPS uses to compute those coordinates. Must match the datum of the map. A handful of other settings — north reference, distance and elevation units, data field choices, battery type, satellite system — affect how usable the GPS is in the field but rarely make the difference between a usable position fix and a wrong one. They're covered here in roughly that order of importance. These settings exist on almost every land-recreation GPS receiver, even though the menu paths and exact wording differ. Most of the concrete examples use Garmin terminology (the eTrex line in particular), because Garmin dominates the recreational handheld market and because the MapTools instructor materials use Garmin units. The concepts travel to other manufacturers; only the button paths change. Position format This is the format your GPS uses to display your current coordinates. The common choices, in roughly the order most useful for land navigation with topographic maps: UTM/UPS — Universal Transverse Mercator, plus the polar variant. The default recommendation for most land users. MGRS — Military Grid Reference System. A specialized form of UTM. US National Grid (USNG) — civilian sibling of MGRS. See USNG Coordinates. hddd° mm′ ss.s″ — latitude/longitude, degrees-minutes-seconds. hddd° mm.mmm′ — lat/lon, degrees and decimal minutes. hddd.ddddd° — lat/lon, decimal degrees. For ordinary land navigation against a topographic map with a UTM grid, set the format to UTM/UPS and the rest of your workflow gets simpler — coordinates plot directly with a UTM tool on the printed grid, with no conversion. The metric basis of UTM also pairs naturally with metric distance units. Pick lat/lon when the people you're working with use lat/lon (sea, air, marine charts, search-and-rescue traffic in some regions) or when the map you're using doesn't have a UTM grid and you have a tool for plotting lat/lon coordinates. Most receivers ship configured for lat/lon decimal degrees out of the box. The first setup step is almost always to change the position format to whatever you actually plan to use. Map datum The map datum is the geodetic reference frame the GPS uses when it converts the satellite-derived position into ground coordinates. The datum setting on the GPS must match the datum of the map you're plotting against. A datum mismatch produces a consistent offset of typically a few hundred meters — large enough to put you on the wrong side of a stream or ridge, but small enough that you may not notice the error until something else doesn't add up. The common datum choices on a recreational GPS: NAD 27 CONUS — North American Datum of 1927, Continental United States. The datum used on most USGS paper topographic maps printed before the late 1990s and on many that are still in circulation. If your map's collar says "NAD 27" or doesn't say anything at all and it's a USGS topo, assume NAD 27. NAD 83 — North American Datum of 1983. The current USGS datum. Essentially identical to WGS 84 for civilian use. WGS 84 — World Geodetic System 1984. The default datum for most GPS receivers as shipped, the datum used on most modern marine charts, and the datum the GPS satellites themselves broadcast against. The single highest-yield setup mistake to avoid: leaving the GPS at its default WGS 84 while using a USGS NAD 27 paper map. This is the most common datum mismatch in the field, and it consistently puts your reported position about 100–200 meters away from where you actually are, depending on where in the continent you are. For more on the geometry — what a datum is, why the offset exists, and how to recognize and correct one in old map data — see Map Datums. A practical habit: any time you pick up a new map, check the collar for the datum and set the GPS to match before you leave the trailhead. Treat it as part of preparing the map. North reference The north reference setting determines what direction the GPS calls 0° / North in any heading or bearing it displays. The common choices: True — bearings and headings are referenced to True (geographic) North. The left and right edges of most topographic maps are lines of longitude, which are also True North references — making True-referenced bearings straightforward to plot. Magnetic — bearings are referenced to Magnetic North, matching readings taken on a compass that has not been adjusted for declination. If you want the GPS bearing and the compass bearing to agree directly, use Magnetic. Most receivers will compute the local declination automatically; some allow manual entry — pick the automatic option unless you have a specific reason to override it. Grid — bearings are referenced to Grid North, the direction the UTM grid lines on your map run. Convenient when plotting bearings on a UTM-gridded map, since the grid lines are everywhere and the bearing plots without any rotation correction. User — manual declination entry. There's no single right answer here; the right choice depends on which other tools you're using. If you're plotting bearings on a UTM-gridded map and rarely sighting them with a compass, Grid is the most convenient choice. If you're sighting bearings with a compass and walking them, Magnetic keeps the GPS bearing and the compass reading numerically identical. If neither of those is dominant, True is the safe general-purpose default. See North References (True, Magnetic, Grid) and Declination for the geometry of how the three norths relate. Distance and elevation units Mostly a preference setting, with one alignment worth honoring: if you've set the position format to UTM, set distance to metric. UTM is a metric grid, your map is gridded in 1-km squares, and your plotting tool measures within those squares in meters. Mixing metric coordinates with statute distances forces unit conversion at every step. If the GPS lets you set elevation units separately, match the units to whatever the map's contour lines and elevation markings use — feet on a USGS topo, meters on most other countries' topographic maps. Data field configuration Most handheld GPS receivers let you configure which data fields appear on which screens. This is one of the differences between a GPS that's useful in the field and one that's mostly screens of irrelevant information. The fields that earn their place on the screens you actually look at: On the Trip Computer / position screen, large data fields: Location (your current coordinates, in your chosen position format) Time of day Battery level GPS accuracy (the receiver's own estimate of position error — see Accuracy vs. Precision) Heading Speed and moving average speed Elevation and vertical speed On the Trip Computer, small data fields (a denser layout for when you're working with mixed audiences) — useful to add a second Location field set to lat/lon while the first stays on UTM, so you can read out either format without changing the position format setting. On the Compass screen: Bearing (direction to the next waypoint) Distance to next (distance to the next waypoint) Heading (your current direction of travel) Destination (the name of the waypoint you're navigating to) On the Map screen: no data fields. The map screen on a handheld is small to begin with; data fields shrink the actual map further, and the same data is already on the Trip Computer and Compass screens. Set the map screen's data field count to 0. The Garmin Profiles feature is worth knowing about: it saves an entire configuration — settings, data field choices, screen layout — under a name, so a group can standardize on a shared profile and individual users can switch between configurations (e.g., a "Class" profile and a personal profile) without losing either. Most other vendors have an analogous feature with a different name. Battery type, satellite system, and other ancillary settings Worth setting once and forgetting: Battery type. Set this to match the chemistry you're actually using — alkaline, lithium, or rechargeable NiMH. The battery-level indicator only reads correctly when this matches; mismatched, the receiver will either report a healthy battery shortly before shutdown or report a near-dead battery with most of its capacity remaining. Satellite system. GPS + GLONASS (or GPS + GLONASS + Galileo, on newer receivers) gives faster fixes and better performance under tree cover or canyon walls than GPS alone, at the cost of slightly higher battery draw. Use the multi-system option unless battery life is the dominant constraint. WAAS / EGNOS. Enables the regional satellite-based augmentation system. Turn it on in North America (WAAS) and Europe (EGNOS); it improves position accuracy noticeably. USB mode. Set to Mass Storage so the GPS appears as a drive when plugged into a computer — easier transfer of waypoints, tracks, and offline maps than the vendor-proprietary mode. How the GPS fits into the workflow Setup is the foundation, not the point. The point is the way the GPS gets used in the field. The pattern that works well for most land users: Carry the GPS turned off, most of the time. Power it on when you specifically want a position fix, wait about a minute for the computed position to stabilize, read off your coordinates, then turn it off again. With this pattern a set of batteries lasts months, not days. Use the GPS for the "where am I?" question. That's what it does best: read off your UTM (or lat/lon) coordinates, plot them on the paper map with a UTM tool, and you have your position to about the size of two parking spaces — anywhere on Earth, day or night, in any visibility. For this specific question, the GPS beats a sighted-and-plotted compass resection handily. For navigation along a planned route, mark waypoints at decision points — places where you change direction, choose between options, or want a confidence check on a long leg. The GPS shows you when you're drifting off-line; the compass alone tells you only what direction you're pointed. For bearing-and-distance work, project waypoints rather than walking compass bearings. Most GPS receivers can create a new waypoint a stated distance and bearing from a known one. The GPS then recalculates a fresh course to the projected waypoint continuously, which means you can detour around obstacles or follow easier terrain without losing the line — the compass-and-pacing approach can't do that. The receiver's built-in Map screen is mostly for confirmation, not for primary navigation. The screen is small, the detail-vs-context trade-off forces constant zooming, and on most units the installed maps are coarser than the paper you're carrying. Use the paper map for the map work; use the GPS for the position fix.

### Introduction to Map Coordinates
https://maptools.com/learn/introduction-to-map-coordinates

What a map coordinate is A map coordinate is just an address for a spot on the Earth — a short set of numbers (and sometimes letters) that names one place precisely enough that someone else can find it. Where a street address relies on streets and house numbers, a map coordinate relies on a grid laid over the world. There are many coordinate systems, not one. Latitude and longitude (lat/lon) is the global one that every GPS and map can speak; UTM, MGRS, and USNG are square metric grids; and there are whole families of national grids besides. They look like unrelated piles of numbers at first, but once you understand the few ideas every coordinate system shares, they start looking like different ways of saying the same thing. This page is the on-ramp. It covers the ideas common to all coordinate systems before you pick one. When you're ready to choose, see Choosing a Coordinate System. Every system has a grid A coordinate system starts by drawing a grid over the map — a set of lines running two directions, like the lines on graph paper. Your position is described by how far along you are in each direction: one number east-west, one number north-south. The grid might be made of curved lines of latitude and longitude wrapping the globe, or it might be a square grid measured in meters. Either way, the principle is identical: two measurements, two directions, one point where they cross. Mapmakers call the drawn grid a graticule when it's the lat/lon network of meridians and parallels, and simply a grid when it's the square metric kind. You'll see both terms; they're the same idea at different scales of formality. Many systems — and a few look-alikes Lat/lon is universal, but it's not the only system you'll meet, and several of the others can fool you. Square metric grids beyond UTM. UTM isn't the only meters-east, meters-north grid. Britain's Ordnance Survey National Grid, the Indian Grid, the New Zealand Grid, and others work the same way — at the scale of a single map sheet their lines plot just like UTM's. The trap is that the numbers are not interchangeable: the same spot carries completely different grid values depending on which national grid it's measured in, because each grid has its own origin and projection. A grid reference is meaningless until you know which grid it belongs to. The Public Land Survey System (PLSS). Across much of the western United States, maps are carved into the PLSS — townships, ranges, and one-mile-square sections. It behaves almost like a coordinate system, and people use it like one, but it isn't a uniform grid: sections aren't perfectly square or perfectly aligned, surveying error accumulates, and correction lines deliberately break the pattern. A common mistake is to glance at the one-mile section squares and read them as the one-kilometer squares of a UTM grid — on a typical topo map they're close enough in size to be confused, and they mean entirely different things. Every coordinate is measured against a datum The grid has to be anchored to a model of the Earth's actual shape. That model is called a datum. It sounds like fine print, but it matters: the same physical spot, measured against two different datums, comes out as slightly different numbers. Mismatch the datum between your map and your GPS and you can land hundreds of meters off. For an introduction you only need to know the word and the warning — set your GPS to match your map. The full story is in Map Datums. Reading order depends on the system Every system fixes the order its two numbers are written in — but the order is not the same from one system to the next, which is exactly why it trips people up. The square metric grids (UTM, MGRS, the national grids) write the east-west value first and the north-south value second: "read right, then up," the way you'd read a graph. Latitude and longitude do the opposite — latitude (north-south) is written first, longitude (east-west) second. So there is no single rule like "east always comes first"; there's only "know your system's order." Getting the order wrong is one of the most common — and most dangerous — beginner mistakes. On a metric grid, swapping the easting and northing doesn't just nudge you to the wrong side of a ridge; both are large numbers, and swapping them can throw you tens or hundreds of kilometers away — the wrong county or the wrong state, not the wrong hillside. The defense is simple: keep each system's convention, and label the parts — E and N on a metric grid, or the hemisphere (N/S and E/W) on a lat/lon pair — so a reader can't swap them. Precision is an area on the ground A coordinate never names an infinitely small dot — it names a small area, and how small depends on how many digits you give. More digits means a smaller area and a more precise location; fewer digits means a bigger one. The shape of that area depends on the system. On a square metric grid, dropping a digit multiplies the cell by ten: a position given to the nearest 10 meters sits in a 10-meter square, to the nearest 100 meters a 100-meter square. Lat/lon isn't square — a degree of longitude shrinks as you move from the equator toward the poles, so the same angular precision covers a tall, narrow rectangle whose width changes with latitude. Either way the idea holds: fewer digits, larger cell. A useful habit: match your precision to what you're describing. Naming a trailhead to the nearest meter is false precision; naming a specific rock to the nearest kilometer is useless. And when you do shorten a coordinate, follow each system's convention — the metric grids want you to truncate (drop the extra digits) rather than round up, so the coordinate still honestly points to the cell you measured. Where to go next Latitude and Longitude — the global graticule, the system every GPS and map shares. UTM Coordinates — a square metric grid that's fast to read on a topo map. Choosing a Coordinate System — how to decide which one fits your trip, your team, and your map. Map Datums — the Earth-model under the grid, and why your GPS and map must agree on it.

### Land Navigation
https://maptools.com/learn/land-navigation

What is land navigation Land navigation is the practice of knowing where you are and finding where you want to go when you're traveling on foot in terrain that isn't laid out with signs and street names. It's a working combination of Map Reading, GPS for Land Navigation, and Compass Uses, (especially Compass Bearings), grounded in an understanding of North References (True, Magnetic, Grid) and Declination and supported by good Route Planning and Following habits. The skill isn't any one tool. It's the mental model that lets a person on a ridge match the lumpy terrain in front of them to the contour squiggles on a paper map, decide where they need to go, pick a route they can actually walk, and notice when their plan stops matching reality. The tools — map, compass, GPS — are aids that fail less often than the mental model does, but they're useless without it. The shape of the skill Land navigation breaks into a few interlocking sub-skills: Reading a map. Recognizing what kind of map you have, reading its scale, finding features on it, and turning a printed sheet into a mental picture of the ground. See Map Reading. Knowing where you are. Locating yourself on the map by matching visible terrain to printed contours, by reading coordinates off a GPS receiver and plotting them, or by resectioning with a compass bearing to a known landmark. Picking and following a route. Choosing a path that's actually walkable, breaking it into legs you can navigate one at a time, and recognizing when each leg ends. See Route Planning and Following. Adjusting when you're wrong. Noticing early that the terrain doesn't match the story you're telling yourself, and revising the story instead of pushing on. Build a "navigation story," check it constantly, and adjust early. My "six steps to becoming a better navigator" framing emphasizes that the skill is built through practice on everyday navigation tasks before it ever gets tested in the backcountry. Tools, not magic Three tools dominate the toolkit: A topographic map. The single most useful artifact a navigator carries. Two-dimensional, durable, weatherproof if you laminate it, and surprisingly information-dense once you can read the contours. See Map Reading and UTM Practice Map. A GPS receiver. Tells you exactly where you are in coordinate terms — but only useful if you can plot those coordinates on a map. See GPS for Land Navigation and GPS Receiver. A baseplate compass. A tiny, reliable instrument that tells you direction. See Baseplate Compass and Compass Bearings. None of these tools navigate for you. They give you facts; you do the reasoning. What goes wrong Most navigation failures in the field aren't tool failures — they're attention failures. The navigator stops checking their position against the map, the map and the terrain quietly diverge, and an hour later they're somewhere they didn't expect. Catching yourself early is a skill worth practicing deliberately — most of these failures are preventable once you recognize the pattern.

### Latitude and Longitude
https://maptools.com/learn/latitude-longitude

What latitude and longitude are Latitude and longitude use angular measurements to describe a position on the surface of the Earth. The system has been in use, with little change, since Ptolemy used it in his first world atlas in A.D. 150. Lines of latitude measure north-south position between the poles. The equator is 0°, the North Pole is 90° north, the South Pole is 90° south. Lines of latitude are all parallel to each other, which is why they're often called parallels. Lines of longitude, or meridians, run between the North and South Poles. They measure east-west position. The prime meridian is assigned the value of 0° and runs through Greenwich, England. Meridians to the west of the prime meridian are measured in degrees west; those to the east, in degrees east. A point like 40.0150° N, 105.2705° W puts you in Boulder, Colorado. How big is a degree? Latitude is straightforward because a degree of latitude represents a constant distance on the ground: 1° of latitude ≈ 60 nautical miles, 69 statute miles, or 111 km. 1 minute of latitude ≈ 1 nautical mile, 1.15 statute miles, or 1.85 km. Longitude is trickier. A degree of longitude represents a varying distance on the ground, depending on the latitude — meridians converge as they head toward the poles, so a degree of longitude shrinks as you head north or south from the equator. Two memory aids that help: "Tropical latitudes improve my attitude" — to remember that latitude indicates north-south position. "Lines of LONGitude are all just as LONG as one another" — visualized on a globe, all meridians run pole-to-pole and are the same length, even though the distance between meridians varies with latitude. Who uses it Mariners and aviators have been the primary users of lat/lon. The system is used worldwide and many different types of maps carry lat/lon markings. Most GPS receivers ship configured for lat/lon as their default factory setting. That means most new GPS users start out using lat/lon coordinates whether they intended to or not. There are other geographic coordinate systems — see UTM Coordinates, MGRS Coordinates, USNG Coordinates — that may be better suited to your task and easier to use, but lat/lon is the universal lingua franca that every other system can convert to. Three formats The same point on the ground can be written three ways. Students need to recognize all three and convert between them. Degrees, Minutes, Seconds (DMS) Written as DDD° MM' SS.S". Example: 32° 18' 23.1" N 122° 36' 52.5" W. This is the most common format used to mark maps. It's also the most cumbersome to work with: there are sixty seconds in a minute (60" = 1') and sixty minutes in a degree (60' = 1°), so arithmetic is base-60. Quarter-minute conversions worth memorizing: 15 seconds is one quarter of a minute, or 0.25'. 30 seconds is one half of a minute, or 0.5'. 45 seconds is three quarters of a minute, or 0.75'. Degrees and Decimal Minutes (DDM) Written as DDD° MM.MMM'. Example: 32° 18.385' N 122° 36.875' W. This is the format most commonly used when working with electronic navigation equipment. Decimal Degrees (DD) Written as DDD.DDDDD°. Example: 32.30642° N 122.61458° W, or with signed values: +32.30642, -122.61458. This is the format you'll find most computer-based mapping systems displaying. Sign conventions in decimal degrees Positive latitude is north of the equator, negative is south. Most programs use negative longitude for west of the prime meridian — but a few do it the other way around. Always check. A working preference: many users (including John) reach for degrees and decimal minutes even when working from USGS maps that are marked in degrees, minutes, and seconds. DDM is the sweet spot — accurate, no base-60 arithmetic, and matches what GPS receivers display. Plotting on a topo map The ticks at the corners of a USGS topo map mark the lat/lon grid. Plotting a coordinate is the operation of finding where a given lat/lon falls on the map sheet. The ruler for this job is a lat/lon ruler matched to your map's scale — a 1:24,000 ruler for a 7.5-minute USGS quad, a 1:50,000 ruler for a 1:50,000 map. A generic ruler has no minute markings, and a lat/lon ruler made for a different scale won't fit your map's grid (see My Lat/Lon Ruler Doesn't Fit the Grid on My Map). Latitude (the easy direction) Lines of latitude are parallel and evenly spaced, so a degree of latitude is a constant distance on the map. Place a lat/lon ruler scaled for your map spanning the latitude lines, where the point falls between them. Orient the ruler north-south. In the northern hemisphere, position the ruler's zero-minute end on the southern latitude line. Read the value at the point and add it to the southern line's latitude. Example: a point marked X reads at the 4' mark on a 37° line → 37° 34' N. Longitude (the harder direction) Because meridians converge, you can't just lay the ruler horizontally between two longitude lines — the ruler's spacing won't match the map's spacing. Place the ruler diagonally spanning the longitude lines, with each end touching a marked longitude line. Slide the ruler up or down vertically while keeping both ends on the longitude lines. Slide until the ruler's edge touches the point you're measuring. Extend the longitude lines above or below the map if you need to. Example: point X reads at the 3.5' mark → 122° 3.5' W. The point of interest is located where the plotted lines of latitude and longitude cross. A custom ruler eliminates the diagonal Plotting longitude diagonally works but is awkward. MapTools' custom MapRulers carry a longitude scale adjusted for a particular latitude — within a 1° to 2° band of latitude, the ruler can be placed perpendicular to the longitude lines and read directly. Easier to use, harder to teach with, since the diagonal method makes the convergence problem visible. Choosing a coordinate system For guidance on when to use lat/lon vs. UTM vs. MGRS vs. USNG, see Selecting a Coordinate System. Further reading on maptools.com Lat/Lon Tutorial — tutorial overview Lat/Lon Definitions — the underlying concepts Lat/Lon Formats — DMS vs DDM vs DD Plotting Lat/Lon — plotting a lat/lon coordinate on a map Common student misconceptions

### Map Datums
https://maptools.com/learn/map-datums

Datum vs. coordinate system These two ideas get conflated constantly, and they're not the same thing: A datum is the underlying Earth-model — the ellipsoid plus the reference points used to measure positions on Earth's surface. It answers "which Earth-model am I measuring against?" (NAD 27, NAD 83, WGS 84, etc.) A coordinate system is the notation used to write a position down — lat/lon, UTM, MGRS, USNG. It answers "how am I writing the position?" The same physical point can be expressed in any coordinate system, and against any datum. Both choices matter: changing the coordinate system reformats the numbers; changing the datum moves the reference frame underneath the point, so the numbers come out slightly different even in the same notation. For a more visual introduction, see the MapTools map datum tutorial. What a datum is Survey a small patch of land and you can treat the ground as flat — the math works. Survey a county, a state, a continent, and Earth's curvature starts to matter: distances and angles measured on a curved surface don't add up the way they would on a flat one. To work at that scale, the surveyor needs a mathematical model of the curved surface. The model is an ellipsoid — a slightly flattened sphere, wider at the equator than pole-to-pole because the spinning Earth bulges. (Some GPS receivers and references call this a spheroid; same thing.) The ellipsoid, plus a network of carefully-measured surveyed reference points with their established coordinates, make up a datum. Before satellites, no surveying party could measure across an ocean. So the practical answer was a separate datum for each region — its ellipsoid chosen as a best fit for that part of the world. Examples: NAD 27 — best fit for North America, anchored at Meades Ranch, Kansas. European Datum 1950 (ED50) — best fit for Europe, established for post-war mapping. Old Hawaiian Datum — best fit for the Hawaiian Islands, anchored on Oahu. Indian Datum — best fit for the Indian subcontinent, anchored at Kalianpur in central India. Once we could measure the Earth from space, none of those constraints applied. A single ellipsoid could be defined as a best fit for the entire planet, with the reference frame anchored to the Earth's center of mass instead of to a single ground station. That's WGS 84 — and it's what every GPS satellite emits coordinates against. Animated illustration of a map datum: a curved Earth surface with a reference ellipsoid model fitted to it and surveyed reference points anchoring the measurement framework A coordinate doesn't float in space — it's measured against the datum's reference points, on the datum's ellipsoid. Change the datum and the measurement framework changes underneath the point, so the same physical spot is assigned slightly different coordinate values — read out as lat/lon or as UTM easting/northing depending on the format. The coordinate changes even though the ground doesn't. The datum is an important component of a coordinate. A coordinate with an unknown datum is an approximate location at best. That said, in practice most coordinates get passed around without an explicit datum label. The datum is usually carried as context (the map's stated datum, the team's standing convention, the GPS's current setting) rather than written next to every number. That's a workable shortcut as long as the context is unambiguous; it stops being workable the moment a coordinate crosses from one context to another without the datum coming along with it. Our understanding of Earth's shape keeps improving, and the tools we use to measure it keep getting sharper. WGS 84 won't be the last datum. The three datums a U.S. user encounters NAD 27 CONUS — North American Datum of 1927. Common on older USGS topographic maps. Terrestrial-based: established from a triangulation station in Meades Ranch, Kansas, before satellite surveying existed. NAD 83 — North American Datum of 1983. Used on most newer USGS maps. Adopted as a world standard before WGS 84 superseded it. WGS 84 — World Geodetic System of 1984. The default datum used by GPS. Space-based: standardized on the center of the Earth, which makes it a good fit for the entire surface of the planet rather than for any particular continent. How big are the offsets? The numbers worth keeping in mind: NAD 83 vs. WGS 84: typically only a meter or two difference. Negligible for navigation. NAD 27 vs. WGS 84: can be as much as 200 meters in the continental U.S., varying by region — enough to put you on the wrong side of a ridge. An incorrect datum can put you hundreds of meters from your actual position. This is the catch that produces "the GPS says I'm here but the map says I'm there" confusion. The map and the GPS are both right within their own datum; they just disagree about what the numbers refer to. How to identify your map's datum On a USGS topographic map, the datum information is in the fine print at the bottom-left of the collar. Check it before you leave the trailhead; check it as part of getting any new map onto the table. Older USGS maps are almost always NAD 27. Newer USGS maps may be NAD 83. Transitional maps sometimes include explicit conversion instructions or a dashed cross in the SW and NE corners of the map giving a visual indication of the offset between the two datums. When the datum isn't stated, the safest default depends on the map's vintage and origin: A modern digital map (anything you printed yourself from a recent source, most third-party hiking maps, marine charts) is overwhelmingly likely to be WGS 84. The civilian world has converged on it. An older USGS paper topo with no stated datum is almost certainly NAD 27. The default predates the modern convention. A map with no printed datum reference and no identifiable vintage or source should be treated as approximate-only until you've verified the datum against a known feature. Don't guess from format alone — coordinates printed on a map look identical in NAD 27 and WGS 84; the difference is only in which Earth-model the numbers refer to. Setting your GPS to match Most GPS receivers designed for land navigation let you change the map datum from the Setup menu. The rule is simple: Always set your GPS unit's datum to match the datum of the map you are using. A practical note about what the GPS shows on the same setup screen: alongside Map Datum you'll usually see a Map Spheroid field. You don't need to set the spheroid separately — it's the ellipsoid component of the datum, and it changes automatically when you change the datum. Selecting NAD 27 sets the spheroid to Clarke 1866; selecting WGS 84 sets it to WGS 84. Treat the spheroid field as informational and ignore it unless you have a specific reason to override. Typical GPS receiver Setup menu showing the Position Format and Map Datum fields side by side, illustrating that these are two independent settings the user must configure See GPS Setup for Map Coordinates for the full configuration walkthrough — position format, datum, north reference, units, and data fields. For mixed-mission work where ground, aviation, and maritime users are coordinating, the tolerance varies. Pilots might tolerate "several hundred meters" of error; a ship in rough seas might not. If precision matters, the datums must match — or coordinates must be converted explicitly before they leave one team for another. Converting between datums or formats using a waypoint A useful field trick when someone hands you a coordinate in a datum or format different from the one you're set up for: use a waypoint as the converter. The procedure on most receivers: Note your current Position Format and Map Datum settings — you'll restore them at the end. Change Position Format and Map Datum on the GPS to match the coordinate as written. (Example: someone gives you N 37° 25.423′ W 122° 12.541′ WGS 84 and you're normally set up for UTM/NAD 27. Switch the GPS temporarily to lat/lon decimal-minutes and WGS 84.) Create a new waypoint and edit its coordinate fields to the values you were given. Save it. Switch Position Format and Map Datum back to your usual settings. Open the waypoint. It now displays the same physical point in your preferred format and datum. This works because the GPS stores the waypoint internally as a fixed position on the Earth and re-renders it through whatever format/datum is currently selected. The same trick converts MGRS to UTM, NAD 27 lat/lon to WGS 84 UTM, and any other pairing the GPS supports — without needing a computer or an online tool. For converting more than a handful of coordinates at a time, switch to a computer-based or web-based conversion tool — the waypoint method is meant for one-off field conversions. Two starting points: The MapTools Coordinate Converter — common conversions in a browser. NOAA's NGS Coordinate Conversion and Transformation Tool (NCAT) — authoritative for U.S. datum transformations. The URL has shifted over time; search "NGS NCAT" if the link is dead. Datums and MGRS / USNG A subtle point that catches users of older maps — the two systems handle datums differently. MGRS was adopted in 1949 and predates WGS 84 by 35 years; it has been used historically with whatever regional datum the local maps were drawn on. The modern convention treats WGS 84/NAD 83 as the implicit default, with NAD 27 handled by an explicit letter-shift convention. MGRS can be used with any datum. There's no formal way to write the datum into the coordinate, but it still matters and should still be specified in any context where the receiver might not be configured for the matching datum. When the datum is NAD 27, MGRS applies a letter shift to disambiguate: the second letter of the 100,000-meter square identifier is advanced by 10 positions in the alphabet (skipping I and O, which MGRS never uses). The rule is the same in every zone. Examples: a second letter of A shifts to L; F shifts to R; J shifts to U. USNG only supports NAD 83/WGS 84 or NAD 27. The default is NAD 83/WGS 84; if NAD 27 is used, the datum must be written explicitly alongside the coordinate, e.g. 10S EH 597 822 (NAD 27). USNG does not shift letters for NAD 27. A worked example for the same physical point under NAD 27: MGRS: 10S GU 0706832 4344683 (the second letter is shifted from J to U) USNG: 10S GJ 0706832 4344683 (NAD 27) (no shift; datum written explicitly) If you encounter MGRS coordinates from old maps with a letter pair that doesn't match what your GPS computes for the same physical point, suspect the NAD 27 shift first. A practical note on format: the abbreviated MGRS short forms (597 822, 5974 8221) made sense when coordinates were sent by Morse code or over a scratchy field radio — keeping the string short was a real operational constraint. Today, modern data links carry the full coordinate easily, and the full easting/northing carries enough redundant information to detect a slipped digit. Default to reporting the full easting and northing as read from the GPS, and match whatever convention the people you're working with have agreed on. Other datums A typical handheld GPS receiver lists more than 100 datums as options — the long tail of regional datums going back centuries. If you're traveling internationally, the safe assumption is that local datums can produce kilometer-scale offsets from WGS 84 — far worse than the NAD 27/WGS 84 case in the U.S. Set the GPS to match the map's datum. The simpler alternative: set the GPS to WGS 84 and carry only WGS 84-referenced maps. How to teach it Common misconceptions

### Map Projections
https://maptools.com/learn/map-projections

What a map projection is A map projection is the method used to take the curved surface of the Earth and lay it out flat on a sheet of paper or a screen. The catch is geometry: you cannot peel a globe and press it flat without stretching, tearing, or squashing some part of it. Every flat map is therefore distorted somewhere — there is no perfect one. The projection is just the systematic set of rules for how a particular map trades one kind of distortion for another. For day-to-day navigation you almost never have to choose a projection or do anything with it directly. What matters is knowing it's there, because it's the reason the lat/lon grid and the UTM grid don't line up as simple squares, and the reason grid systems and UTM zones exist in the first place. Why flat maps are always distorted The Latitude and Longitude grid of parallels and meridians draws cleanly on a globe. But the globe's surface can't be flattened without distortion, so a perfect flat map is impossible. This is the "orange peel" problem: try to lay a peeled globe flat and you either tear it or squash it. The "orange peel" problem — the earth is round, maps are flat, and there's no way to go from one to the other without something tearing or squashing The "orange peel" problem: the earth is round, maps are flat, and there's no way to go from one to the other without something giving. The usual trick is to wrap the globe in a simple shape you can unroll flat — a cylinder, a cone, or a plane laid against it — project the grid onto that shape, then cut it open and lay it out. A 2D illustration of projection: a light source inside a globe casting the grid outward onto a flat surface The projection mechanism in miniature: a light source inside the globe casts the grid outward onto a flat surface. The three basic projection surfaces — planar, conic, and cylindrical — each wrapped against a globe The three basic projection surfaces: planar, conic, and cylindrical, each wrapped against the globe. Different wrapping shapes and different projection rules preserve different things: some keep shapes correct in any small area, some keep areas in true proportion, some keep directions true. No single projection does all of them at once, which is why so many exist — each is good for some jobs and poor for others. The classic illustration is the Mercator projection, where the meridians become evenly spaced vertical lines. It's excellent for charting a steady compass course as a straight line, which is why it became standard for marine and air navigation. But it badly exaggerates size toward the poles — on a Mercator map Greenland looks larger than South America, even though South America is many times bigger. The Mercator projection of the world, with the characteristic grid of straight vertical meridians and curved horizontal parallels The Mercator projection — straight vertical meridians make it excellent for plotting a steady compass course, at the cost of exaggerating size near the poles. The same ground looks different depending which projection drew it. Below, three projections of the same area of the United States — Mercator, Lambert Conformal Conic, and un-projected latitude/longitude — are overlaid on each other; where the lines diverge is the distortion. Three map projections — Mercator, Lambert Conformal Conic, and un-projected lat/lon — overlaid on the same map of the continental United States, showing how they diverge Three projections of the same area — Mercator, Lambert Conformal Conic, and un-projected lat/lon — overlaid. Where the lines diverge is the distortion. The projection a land navigator actually meets The one that underlies most modern land-navigation maps is the Transverse Mercator. It's the Mercator idea turned on its side: instead of wrapping the cylinder around the equator, it's turned to touch the globe along a chosen meridian (a north-south line). That keeps scale and angles very accurate in a narrow north-south strip on either side of that meridian — exactly the right tradeoff for a continent's worth of mapping done in tall, skinny slices. A comparison of normal, transverse, and oblique aspects for cylindrical, conic, and planar projections Normal, transverse, and oblique aspects, for each of the three projection surfaces. Transverse Mercator is the cylindrical case turned on its side — the middle column, top row. This is the foundation of the UTM grid: the Earth is divided into UTM Zones six degrees of longitude wide, and each zone gets its own Transverse Mercator projection centered on its own meridian. Slicing it into zones keeps the distortion within any one zone small enough that you can treat the UTM grid as a flat, square, meters-based grid and measure distances and bearings on it directly. That's the whole payoff: a grid you can do simple flat-paper math on, made possible by a projection chosen to keep error tiny within each zone. A projection is a different thing from a datum and from Map Scale: the projection is how the round Earth gets flattened, the datum is which Earth-model the coordinates are measured against, and the scale is how much the map is shrunk. A complete map specifies all three — you'll find the projection named in the fine print of the map's margin alongside the datum. Other projection families you may see named Transverse Mercator isn't the only projection you'll run across by name. Two others show up often enough to recognize on sight, even without going deep on the math: Lambert Conformal Conic projection of North America, showing the fan-shaped grid characteristic of a conic projection Lambert Conformal Conic projection of North America — a conic projection, common on aeronautical sectional charts. Stereographic projection centered on the North Pole Stereographic projection centered on the North Pole — a planar projection, useful for polar regions where cylindrical projections like Mercator break down.

### Map Reading
https://maptools.com/learn/map-reading

What is map reading Map reading is the practice of extracting useful information from a printed map — where things are, how far apart they are, what kind of terrain lies between them, and which routes between them are actually walkable. For wilderness use the relevant map is almost always a topographic map — a sheet that uses contour lines to depict elevation, alongside the planar features (rivers, trails, roads, structures) that other maps would show. You can read a map at three depths: Recognizing features. "That's a river, that's a trail, that's a peak." Reading the geometry. "The trail is 1.4 km long, climbs 200 m, and bends north halfway." Requires Map Scale, and the contour-line conventions. Picturing the ground. "If I stand at that saddle, the ridge to my right will be steep and rocky and the valley to my left will open up to the west." This is the hardest skill and the one the Wilderness Navigation Fundamentals class builds the most deliberately. Using your map with your gps Knowing how to relate coordinates from your GPS to positions on your map, will give you fast and accurate answers to the "Where am I?" question. Reading a coordinate from the map, will allow you to create a waypoint in your GPS, which can then provide you with realtime bearing and distance to the point. Requires map-datum, GPS Setup for Map Coordinates, UTM Coordinates or Latitude and Longitude. Most navigation failures in the field happen because the navigator stalled at depth 1 or 2 and never built the depth-3 picture. What's on the map A standard USGS 7.5-minute (1:24,000) topographic map carries, around its edges and across its face: Scale and distance markers. See Map Scale for the math; the printed bar scale at the bottom is the practical reference. A grid. UTM, lat/lon, or both. The map's coordinate system controls how you read positions off it. See UTM Coordinates and Latitude and Longitude. Contour lines showing elevation. The interval is printed near the legend. A declination diagram showing the angle between true north, magnetic north, and (sometimes) grid north for the map's location and date. See North References (True, Magnetic, Grid) and Declination. A datum statement. What earth model the map coordinates are based on. Matters when comparing the map to a GPS reading. See Map Datums. Map projection and zone information. For UTM-grid maps, the zone designation. See UTM Zones. Date of survey. Maps go stales. Man made features can change over the years, roads and trails move or fade away, and new one are created. Terrain features also change over time, rivers and streams find new courses. The Earth's surface slowly erodes under the influence of wind and water. Landslides, earthquakes, and volcanos may make more rapid changes. The legend tells you what every symbol means. The first thing to do with any unfamiliar map is read its legend. Reading contour lines A contour line connects points of equal elevation — every point along one line sits at the same height above sea level. The contour interval is the constant vertical distance between one line and the next; it's printed in the map's margin near the scale. On a 40-foot-interval map, every line you cross going uphill is another 40 feet of climb, whether the lines are crowded or spread apart. Contour lines are the topographic map's defining feature and the source of most of its useful information: Closely spaced lines mean steep ground. Widely spaced lines mean gentle ground. Concentric closed loops mean a hilltop (or, less commonly, a depression — look for hachure marks). A V or U pointing uphill marks a drainage — a valley or draw. (Where contours cross a stream, the V points upstream.) A V or U pointing downhill marks a spur or ridge — a finger of high ground. This is the introductory treatment. For the full picture — index vs. intermediate contours, reading slope, the terrain features (ridge, valley, spur, saddle), and spot elevations — see Elevation and Topography. A navigator who can read contours can see terrain in the printed sheet. A navigator who can't is essentially using a road map. Map types beyond the USGS topo A navigator encounters a range of map types: USGS topographic at various scales (1:24,000, 1:62,500, 1:100,000), Forest Service maps, trail maps, road maps, nautical charts, aeronautical sectionals, orthophotos, Google's web maps, and military Joint Operations Graphics. Each has its uses; each fails for some uses. The skill is recognizing which map fits the task. What can't a map tell you Maps lie by omission. Common things that aren't on the map: Whether the trail is actually walkable today (deadfall, washouts, snow). Whether the land is open to public access — just because a route is on your map doesn't mean you're allowed to travel it. Whether the contour at 100m intervals has missed a 20m cliff band inside that interval. (For most USGS topos: yes, occasionally.) Where the parking actually is, if the trailhead has moved since the map was surveyed. The map is a tool, not a guarantee.

### Map Scale
https://maptools.com/learn/map-scale

What map scale is Map scale is the relationship between a distance on the map and the corresponding distance on the ground. It tells you that some distance on the paper stands for some larger distance on the ground. The same relationship can be expressed three different ways, and a single map often shows it in all three at once. Three representations of the same scale The three representations are three views of the same relationship — each with its own strengths and weaknesses. Ratio: 1:24,000. Unit-free. One unit on the map equals 24,000 of the same unit on the ground. Works in millimeters, inches, fathoms, or anything else — provided you use the same unit on both sides of the colon. Distance equivalence: 1 inch = 1 mile or 1 cm = 1 km. A concrete statement in named units. Just as exact as the corresponding ratio: 1 inch = 1 mile is 1:63,360, because a mile is made up of 63,360 inches. Scale bar: the printed ruler in the map margin — a labeled visual reference calibrated to the printed map. A 1:63,360 ratio, the equivalence "1 inch = 1 mile," and a printed bar one inch long labeled "1 mile" are all the same scale. There is no hierarchy among them; they're three notations for one relationship. Strengths and trade-offs Each representation does some things well and other things badly. Working navigators use all three, often on the same map. Ratio. The most portable form. Works in any unit, on any tool. The trade-off is abstraction: 1:50,000 doesn't immediately tell you "how far is that?" without you doing arithmetic. It also depends on the printed image being at its original size — print the map through a dialog set to "fit to page" or "scale to fit," or photocopy it at 80%, and the printed 1:50,000 text still says 1:50,000 while the actual ratio is no longer 1:50,000. Distance equivalence. The most immediately interpretable form. "One inch is one mile" lands without arithmetic. The trade-off is unit-specificity: change your ruler's units or the map's printed units and the equivalence has to be recomputed. Same vulnerability as the ratio when the paper is printed at the wrong size — the printed equivalence keeps saying the old thing. Scale bar. The only representation that survives a resize of the printed page. Shrink the map — by photocopy, by a print dialog set to "fit to page," by any scaling adjustment short of 100% — and the bar shrinks along with the rest of the image. Measure against the bar and you still get the right answer. The trade-off is precision: eyeballing a bar scale is less accurate than measuring with a ruler against a trusted ratio, and the bar is only as long as the map margin gave it room to be. Common scales and their clean equivalences The same 1:N ratio can produce a clean equivalence in one unit system and an awkward one in another. Mapmakers tend to pick ratios that produce a round number in their working units. Neither system is inherently better — both produce exact ratios; both produce clean equivalences for some ratios and ugly ones for others. Ratios with clean metric equivalences: 1:100,000 — 1 cm = 1 km (or 1 mm = 100 m). 1:50,000 — 2 cm = 1 km (or 1 mm = 50 m). 1:25,000 — 4 cm = 1 km (or 1 mm = 25 m). Ratios with clean imperial equivalences: 1:63,360 — 1 inch = 1 mile, exactly. 1:24,000 — 1 inch = 2,000 feet, exactly. The standard USGS topo scale. 1:31,680 — 1 inch = ½ mile, exactly. These are all just ratios. 1:24,000 is no more "imperial" than 1:25,000 is "metric" — the ratios are unit-free. The one practical consequence: tool scale must match map scale. Using a 1:24,000 ruler on a 1:25,000 map produces silently-wrong distances at about a 4% error — small enough to escape notice on short legs, large enough to compound into significant offsets on a multi-mile route. For any equivalence not on these lists — miles per inch on a 1:24,000 map, meters per millimeter on a 1:63,360 — the Scale Calculator at https://maptools.com/scale-calculator does the conversion for any ratio and unit combination. Choose a map scale appropriate for your needs Different scales suit different jobs, and the right scale for a trip is set by how fast and how far you're going to move across the ground. A 1:24,000 map (the standard USGS topo scale) shows individual trail switchbacks, small creeks, and building outlines — every detail a hiker on foot wants to see. But you can drive across that same map in just a few minutes. For a 4x4 trip across a region, a 1:100,000 or 1:250,000 map serves you better: less terrain detail per square inch, but the area you're going to traverse in a day fits on the page. This is the larger vs. smaller scale distinction, and the terminology runs backwards from intuition. 1:24,000 is the larger scale — 1/24,000 is a larger fraction than 1/100,000 — so a larger-scale map shows more detail on less ground. A 1:100,000 map is the smaller scale: less detail, more ground covered. "Large-scale map" means bigger ratio, not bigger sheet of paper. Pick the scale to match the trip. A 1:24,000 topo is the right map for picking your way through trail intersections on foot; a 1:250,000 is the right map for planning fuel stops along 200 miles of forest road. Both are good maps for the question they answer. Digital maps and continuous scale On a digital map (web maps, mobile mapping apps), scale isn't fixed — zoom continuously and the map-to-ground ratio changes with every scroll. Map scale as a fixed property applies to paper maps at a single printed scale. Grid squares as a sanity check Where a grid is printed on the map, each cell is a square of known ground size — and you can use that to check, or recover, the map's scale. The grids you're likely to see: UTM grid lines. Typically at 1,000 m intervals on topographic maps; sometimes finer (100 m, 10 m) on detail-heavy or specialty maps. Public Land Survey sections. Nominally one square mile across most of the western and central United States. Measure one cell in millimeters, treat that as a distance equivalence, and convert to a ratio. A Public Land Survey section that measures 67 mm on the map gives you 67 mm = 1 mile. The Scale Calculator turns that into about 1:24,000 — close enough to confirm the printed scale on a USGS topo, or to recover the scale on a map that doesn't print one. This works for the same reason the scale bar does: the grid is printed at the same time as the rest of the map. Resize the page and the grid resizes with it; the derived ratio still describes the map you're holding. Map distance vs. terrain distance A map measures distance on a flat 2D projection of the ground. Map scale converts between map distance and that flat projection. It does not account for elevation change. A 5 km map-distance route across the side of a mountain is more than 5 km of actual walking — sometimes substantially more. The map flattens the terrain; the path you take over it does not. This matters for trip planning (time, water, food, daylight) and barely matters for plotting coordinates. The Map Math Sheet has a one-frame figure showing the effect — a flat map distance arrow with footprints climbing up and over the ground beneath it. For the explicit math The MapTools Scale Calculator handles the arithmetic when you have two of the three quantities — map distance, ground distance, scale ratio — and want the third. For more on scale-ratio calculations and distance-equivalence conversions, see the printable Map Math Sheet. Further reading on maptools.com Metric Measurements tutorial — converting between metric units when working with map distances How to teach it Common student misconceptions

### Map Types
https://maptools.com/learn/map-types

The maps a navigator actually encounters There is no single "right" kind of map — there's the right kind for the job in front of you. A map is a deliberate selection of what to show and what to leave out, and different maps make different choices. The hiker picking through trail switchbacks wants a different map than the driver crossing a region of forest road, and both want something different from the pilot or the boater. Knowing the common types — what each one shows, what it leaves out, and what it's good for — is the first step in choosing well and in reading whatever ends up on your table. The kinds you'll meet most often: Topographic maps — show terrain relief with contour lines, plus natural and man-made features. The navigator's default. Planimetric maps — show position and features but no relief. Road maps and street maps are the everyday example. USGS quadrangles — the standard government topographic series for the United States. Recreation and trail maps — published by parks, forests, and outdoor companies for a specific area and activity. Digital and online maps — web and app maps, and the printable maps you generate from them. Topographic maps A topographic map shows the shape of the land, not just what's on it. Contour lines give you elevation and slope; layered on top are water, vegetation, roads, trails, and structures. Because it carries relief, a topo map lets you plan a route by effort and terrain, not just by distance — you can see the ridge you'd have to cross and the valley you could follow instead. For wilderness navigation on foot, this is the map you want. Reading one well is its own skill; see Elevation and Topography for contour interpretation and Map Reading for symbols, colors, and the marginal information. Planimetric maps A planimetric map shows features in their correct horizontal position but leaves out elevation entirely. The classic case is a road map: it tells you the highway goes from A to B but says nothing about the mountain pass in between. Planimetric maps are excellent for what they do — getting from place to place along established routes — and a poor choice for off-trail travel, where the relief they omit is exactly what you need. USGS topographic quadrangles The U.S. Geological Survey publishes the standard topographic coverage of the country as quadrangles ("quads") — each sheet bounded by lines of latitude and longitude. The familiar 7.5-minute quad is printed at 1:24,000, the workhorse scale for foot travel: detailed enough to show individual switchbacks, creeks, and buildings. USGS prints both lat/lon and UTM references on its large-scale maps, which makes them friendly to any coordinate system you prefer. One catch worth knowing: older quads use older datums (often NAD 27), so check the Map Datums in the collar before you match your GPS to the map. Recreation and trail maps Parks, national forests, and outdoor publishers produce maps tailored to a specific area and activity — trail maps, ski-area maps, marine charts, off-road maps. The good ones are wonderful: current trail data, points of interest, and information a general topo won't carry. They vary widely in quality, though. Two things to check before trusting one: Coordinate references. Some carry a full UTM or lat/lon grid; many carry only approximate ("decorative") lat/lon marks that look authoritative but aren't. Verify before you rely on them. Datum. Most modern third-party maps are WGS 84, but confirm rather than assume — see Map Datums. Digital and online maps Web maps and mobile apps are now where most people start. They're searchable, current, and let you generate and print a custom map at the scale and coverage you want. Two things change when a map goes digital: Scale isn't fixed. Zoom continuously and the map-to-ground ratio changes with every scroll. A printed scale ratio only applies to a paper map at a single printed size — and if you print through a "fit to page" dialog, the printed ratio is wrong while the bar scale stays right (see Map Scale). The datum is usually WGS 84, which lines up cleanly with what your GPS reports out of the box. The strength of digital maps is flexibility; the weakness is dependence — batteries, signal, and a screen you can't read in the rain. A printed map and the skill to read it remain the backstop. For Map Reading fundamentals that apply across every type here, start there. How to teach it

### MGRS Coordinates
https://maptools.com/learn/mgrs-coordinates

What MGRS is MGRS (Military Grid Reference System) is the alphanumeric packaging that the U.S. military and NATO use for the same underlying grid as UTM. A complete MGRS coordinate looks like: 10S GJ 06832 44683 GPS receiver displaying an MGRS position Five parts: 10S — Grid Zone Designation. The UTM zone number (1–60) and the latitude band letter. Necessary to make the coordinate unique over the entire globe. GJ — 100,000-meter Square ID. A two-letter code identifying a unique 100km square within the grid zone. 06832 — the Easting: east-west position within the 100km square, in meters. 44683 — the Northing: north-south position within the 100km square, in meters. Annotated topo map showing where each part of the MGRS coordinate is read from The same map grid lines are used for both MGRS and USNG; the difference is in how the position is written. Precision is the number of digits MGRS coordinates carry their precision in the digit count. Truncating digits is lowering precision; you don't add digits to gain precision. Form Precision Example 10S GJ 06832 44683 1 m full 10S GJ 0683 4468 10 m drop trailing digit 10S GJ 068 446 100 m drop two 10S GJ 06 44 1 km drop three 10S GJ 0 4 10 km drop four 10S GJ 100 km square only When using less precise representation, it is important to truncate rather than round the Easting and Northing values. The Easting and Northing always refer to the southwest corner of the grid square. Adding digits you don't actually have ("digits we don't have") is dishonest in SAR or military-coordination contexts, where the receiver assumes the precision is real and may make decisions accordingly. Reading the easting and northing on a map For the easting: The first two digits come from the large type on the label of the grid line to the west of the position. The last three digits are the distance in meters measured east from that western grid line. The northing follows the same logic against the southern grid line. Close-up of UTM grid line labels along the bottom edge of a topo map The label 706 is shorthand for 706000m E ("seven hundred and six thousand meters East") — the small superscript digits on the label tell you the full value, while the large type is what you read off when writing the easting. A 1:24,000 USGS topo map prints UTM grid lines spaced every kilometer (every 1000 meters). The 1:24,000 Pocket-Sized Slot Tool (UTMSlot24) ruler measures the meters within a 1km square; combined with the gridline labels, it produces an MGRS coordinate to 10-meter precision. Slot-style MGRS plotting ruler positioned on a topo map to read 10-meter precision Writing and saying it The MGRS standard says, for machine-to-machine communication, an MGRS string should have no intermediate spaces or punctuation marks and all letters capitalized. For human communication, do the opposite: I would encourage you to use spaces when writing MGRS coordinate strings, and to pause briefly between logical parts when communicating MGRS coordinate strings verbally. "One zero sierra · golf juliet · zero six eight three two · four four six eight three" is harder to mishear than the same string read as a continuous run of characters. Datum The MGRS standard has no formal way to specify the datum in the coordinate string itself. By convention, MGRS defaults to WGS 84. The trap: MGRS coordinates from older maps may be referenced to NAD 27, in which case the second letter of the 100km square ID shifts by ten letters (excluding I and O) compared to the WGS 84 form. The same physical point can be written as: WGS 84 MGRS: 10S GJ 06832 44683 NAD 27 MGRS: 10S GU 0706832 4344683 If you encounter MGRS that looks unfamiliar against a known location, suspect a datum-shift letter. See Map Datums and USNG Coordinates for the parallel handling in USNG (which doesn't shift letters but requires datum to be specified explicitly). Downloadable NAD 27 / WGS 84 letter-pair charts. MapTools maintains two reference charts of the 100km square identifiers — one for WGS 84 (the primary chart, used on the maptools.com 100km Square Identifiers tutorial) and a second for older datums (NAD 27) that incorporates the second-letter shift. Print-sized 2× versions are linked from that page: WGS 84 chart: 100kmGridIDChart2x.png NAD 27 chart: 100kmGridIDChartAlt2x.png 100,000-meter Square ID lookup chart for older datums (NAD 27), with the second letter pre-shifted Converting MGRS to UTM (and back) MGRS and UTM are the same physical grid — different notations for the same point. Conversion is mostly mechanical: you trade the two-letter 100,000-meter Square ID for the leading digits of the UTM easting and northing (and vice versa). MGRS → UTM. The two-letter square ID tells you which 100km × 100km block of the zone you're in. Each letter pair encodes a specific offset from the zone's reference point: The first letter identifies a column running east-west (in 100km steps from the zone's central meridian). The second letter identifies a row running north-south (in 100km steps from the equator, cycling every 2,000km because letters repeat). Once you know the column and row offsets, you prepend them to the 5-digit easting and northing to reconstruct the full UTM coordinate: MGRS: 10S GJ 06832 44683 The pair GJ in zone 10S resolves to easting offset 7 (hundreds of km) and northing offset 43 (hundreds of km). UTM: 10S 706832 4344683 — the 7 and 43 are the digits the pair encoded. The encoding isn't arithmetic — it's a lookup table that depends on both the letter pair and the grid zone. For the full table and worked examples, see the MapTools 100km Square Identifiers tutorial, or just use the Coordinate Converter tool, which performs the lookup automatically. 100,000-meter Square ID lookup chart showing letter pairs against UTM easting and northing offsets Worked example: locating the GJ letter pair on the chart for zone 10S using easting 700,000m and northing 300,000m UTM → MGRS. Drop the leading digits of the easting (typically 1) and northing (typically 2) and replace them with the matching letter pair from the same lookup table. The remaining 5 digits of easting and 5 digits of northing become the meters-within-the-square portion of the MGRS coordinate. For more than a handful of conversions, don't do this by hand — the lookup table is non-obvious and slipping a letter pair produces a kilometer-scale error with no visual clue. Use the Coordinate Converter. When to use MGRS vs. UTM vs. USNG All three are the same grid; the question is which packaging to use: UTM — raw numerical form. Easting and northing in full meters from a zone reference. Best for survey work, GIS handoff, and any context where the explicit numerical values matter. MGRS — alphanumeric form with the 100km square prefix. Best for military, allied military, and SAR operations where the standard is in use. The 100km letter pair acts as a transmission-error sanity check. USNG — civilian U.S. equivalent of MGRS, used by FEMA and U.S. emergency-response agencies. Effectively identical to MGRS at WGS 84/NAD 83 precision. Per the MapTools coordinate-system guidance: pick the system your peers are using, then worry about ergonomics. Mismatched systems between teammates are how coordinates get mistransmitted. Common errors It is easy to make a mistake using truncated position formats. Slipping a digit left or right results in a very different position. Worse, there is no visual clue that an error has been made until the coordinate is plotted. The chief causes of student error: Mistaking the latitude band letter (one letter, e.g. S) for part of the 100km square ID (two letters that follow). Worth saying out loud once. Slipping a digit between easting and northing — the coordinate looks plausible but lands kilometers off. Truncating inconsistently. Pick a precision and write all your coordinates at it for a session. Choosing a coordinate system For guidance on when to use MGRS vs. lat/lon vs. UTM vs. USNG, see Selecting a Coordinate System. Further reading on maptools.com Interactive UTM Tutorial — the animated tutorial set to MGRS. Because MGRS relabels the same grid, every step is the same as UTM's; what it adds is showing where the grid zone and square letters are copied from on the map, and what the datum tag rule looks like in practice. MGRS Quick Guide — tutorial walkthrough of reading and writing MGRS MGRS vs USNG Differences — how MGRS and USNG diverge on datum handling 100km Square Identifiers — what the two-letter square ID means Common student misconceptions

### North References (True, Magnetic, Grid) and Declination
https://maptools.com/learn/north-references

The three norths A bearing is "the angle clockwise from north" — but which north? Three answers, all in active use, all slightly different. True North — the axis of the Earth's rotation. Lines of longitude (meridians) converge at the true North and South Poles. The North Star sits nearly above the true North Pole; that's what made celestial navigation possible. Magnetic North — the direction the Earth's magnetic field points. A free-floating magnetic needle in a compass aligns with the field and points to the magnetic poles. The magnetic poles are not the true poles, and they drift over time. Grid North — the north reference of a UTM-style flat grid printed on a map. Grid North is useful because it lets you use the UTM Coordinates grid lines on the map as your north reference. It differs slightly from True North; how much depends on your position within the UTM zone. These three are different physical directions. Every bearing you take is implicitly referenced to one of them. When you plot a bearing using the printed UTM grid on your map, you've just used Grid North as your reference — and Grid North isn't True North. The angles between them True North is the geometric reference. Magnetic North and Grid North are described by their angle and direction relative to True North. Declination — the angle and direction of Magnetic North relative to True North. In the continental U.S., declination ranges from roughly 10° east to 20° west. This is the big one — the angle every compass user has to account for. Grid convergence (sometimes "grid variance") — the angle and direction of Grid North relative to True North. Stays inside a 2° band over most of a UTM zone, grows toward zone edges and at high latitudes. The difference between Magnetic North and Grid or True North changes depending on your location. It also changes with the passage of time. Get current values for your location from the declination diagram on your map (with the caveat that it may be out of date), the NOAA declination calculator, or the MapTools Declination Reference Sheet tool. Your tools each have a north reference The three norths aren't abstract: they live in your tools. Each of your navigation tools — compass, map, GPS — carries one or more specific north references. Knowing which is which is the difference between a tool you can trust and a tool you're guessing with. The compass measures bearings against Magnetic North by default. Many compasses have an adjustable declination bezel that offsets the needle reading so the compass reports bearings against True or Grid North instead. The adjustment is correct only for the location and date it was set for; move significantly or wait long enough, and the setting needs to be checked. The map has its north reference baked into its lines. A USGS topo with a UTM grid uses Grid North along the grid lines and True North at the map edges. The declination diagram in the margin shows the offsets between all three. The GPS receiver can be configured to display bearings against any of the three norths. The setting is usually under Setup → Heading or North Reference. A common failure mode: you don't actually know which north reference your compass is set to — "a friend set it up for me a while back — I'm not sure" is the real answer that comes up. That compass is effectively useless until the setting is verified. Same logic for a borrowed GPS or an unfamiliar map. Moving a bearing between tools When you move a bearing from one tool to another, the math depends on which norths the two tools are using. A bearing on a magnetic compass and the same direction on a grid map are different numbers. You can sidestep the per-bearing conversion by configuring your tools to share a north reference: a declination-adjusted compass paired with a grid map needs no conversion at the moment of use. You've paid the conversion cost once, at compass setup, instead of every time you move a bearing. When your tools don't share a reference — un-adjusted compass and a grid map, or a GPS set to magnetic and a map drawn to grid — every bearing transfer is a conversion. Apply the procedure explicitly (see Converting between north references) and don't rely on memory. Setting up your tools Each tool needs a setup. The map: identify what north references are printed and decide which to use. The compass: pick a strategic stance. The GPS: set the right menu option. Setting up your map The map isn't configured the way a compass or GPS is — its north references are baked in. Setup means identifying what's there and choosing which to use. Identify the available north references. Lat/lon lines (or map edges aligned with lat/lon) give you True North. The UTM grid gives you Grid North. A few maps include Magnetic North reference lines; some users draw their own. Look at how many reference lines are available. A protractor needs a nearby reference line to align with. Just the map edges aren't enough — they're often far from the bearing you're measuring. The UTM grid offers numerous reference lines and is the practical choice for most maps that have it. Add lines for a missing reference, if needed. A common move: pencil in Magnetic North lines on a UTM-gridded map so you can plot magnetic bearings directly. Decide which reference you'll use. Pick one and use it consistently. Setting up your compass How you handle the three norths depends on how you set up your compass. Pick one strategy and be consistent — half-measures (sometimes adjusting, sometimes not, never sure which) are a good way to get lost. "Set your compass and forget it" Adjust the compass's declination bezel once for the local declination. From then on, all bearings the compass reads are grid (or true) — no conversion needed for map work. Don't forget to check the setting occasionally. Don't forget to change it when you go somewhere else. An incorrectly adjusted compass is useless for anything beyond a general sense of direction and may be worse than no compass at all. "Set your compass to 0° and always think about it" Leave the compass un-adjusted. All bearings are magnetic. Convert to Grid or True when doing map work, or draw Magnetic North reference lines on the map. This works with any compass, including fixed-bezel ones. It costs you a conversion every time, which is fine at a desk and tiring in the field. Setting up your GPS Your GPS can be set to use any of the three north references. The choice is usually under Setup → Heading or North Reference. Some receivers offer "Automatic," which means the GPS calculates the local declination and displays bearings relative to Magnetic North. Match the GPS's north reference to whatever north reference you're using on the map and compass. Mismatches produce silent disagreements that are hard to trace once you're in the field. Converting between north references When two of your tools use different norths, the same direction has different bearing values. Converting between them is a geometric problem you can work out directly on the declination diagram printed on most topo maps. The declination diagram on a topo map Most paper maps print a small declination diagram showing the three north references relative to one another. It typically includes: An arrow pointing to the top of the map, parallel to the map edges. This is the "top of the map" north reference — for USGS topos this is True North. A second arrow showing the declination angle to Magnetic North, with the angle labeled in degrees and the date the angle was determined. A third arrow showing Grid North (the convergence angle from True North), if the map carries a UTM grid. Useful exercise: trace a bearing line from a fixed point and add it to the diagram, so you can see what the same line looks like measured against each of the three norths. The line doesn't change; only the angle from the reference changes, depending on which arrow you measure from. The conversion procedure If you have a MapTools Declination Reference Sheet for your location, the diagram with bearing line, arcs, and conversion angle is already drawn for you — skip to step 4. Otherwise, work it through on the declination diagram on your map: Add a bearing line to the diagram, representing the direction you want to convert. Aim for something between about 45° and 90° from True North; the exact angle isn't critical. Identify the two north references you're converting between, and draw arcs clockwise from each reference line to the bearing line. Each arc is the bearing to your target from that north reference. Identify the conversion angle. It's the angle between the two north reference lines on the diagram, read directly from the printed values: declination for True ↔ Magnetic, grid convergence for True ↔ Grid, or their combination for Magnetic ↔ Grid. (Use the NOAA declination calculator if the printed values are dated.) Identify which north reference gives the larger bearing to the target. Apply the conversion: Larger-bearing reference → smaller-bearing reference: subtract the conversion angle. Smaller-bearing reference → larger-bearing reference: add the conversion angle. A worked example Declination diagram with a bearing line: Grid North (GN) drawn vertical and Magnetic North (MN) 5° east of GN; a green bearing line to a target (house icon) measured at 60° from Magnetic North (the compass reading) and 65° from Grid North (the bearing to plot on the map), with leader lines labeling each arc and showing 60°M + 5° = 65°G. You're using Grid North on the map and Magnetic North on the compass. From the declination diagram, the angle between Grid North and Magnetic North is 10° — that's your conversion angle. The arcs show that the Magnetic bearing to the target is larger than the Grid bearing. Therefore: Magnetic bearing = Grid bearing + 10° Grid bearing = Magnetic bearing − 10° Why precision doesn't matter as much as you think You are probably fooling yourself if you think you need more than one degree precision. A 1° error in declination produces about a 90-foot offset per mile traveled. That's enough to matter on a multi-mile route — but between compass needle drift, hand-held bezel-reading error, anomalous declination at the local site, and step-counting drift, sub-degree precision washes out long before it matters in the field. Survey work is different. Foot navigation is not. Don't kid yourself about precision. The goal is to be correct to the nearest degree, not perfect. Anomalous declination Declination varies smoothly over most of the continent — but not everywhere. Local magnetic anomalies (iron ore, basalt outcrops, even some buildings) can deflect a compass needle from the regional value, sometimes by a lot. Examples from the field: 3-4 degrees is common North of Kingston, Ontario; 90° of anomalous declination. Kingston Harbor, Ontario; 16.3° W to 15.5° E of anomalous declination over two kilometers (1.2 miles); magnetite and ilmenite deposits. Savoff, Ontario (50.0 N, 85.0 W). Over 60° of anomalous declination. Ramapo Mountains, northeastern New Jersey; iron ore; compass rendered useless in some areas. Near Grants, New Mexico north of the Gila Wilderness area; Malpais lava flows; compass rendered useless. If your compass and your map persistently disagree by an unexpected amount in a particular spot, the ground may be the culprit, not your math. If you are in unfamiliar terrain, do a sanity-check bearing between two known features before you rely on your compass for real navigation. Application by audience Different communities default to different norths, which is why "say which north" matters so much in cross-community work. Aviation and marine charts often have pre-printed Magnetic North lines. Most other maps do not. Military, SAR, and UTM/MGRS-gridded maps make Grid North prominent — the dense UTM grid lines are the working north reference. Civilian backcountry on a USGS topo prints Grid North on the UTM grid and True North on the lat/lon lines and edges. Magnetic North isn't printed, though some users draw their own Magnetic North reference lines. Users typically pick grid or magnetic, depending on their compass setup. Group conventions Many organizations adopt an internal standard north reference — everyone agrees, for instance, to use grid bearings. The convention saves on conversions when everyone shares the reference, but two caveats apply: The convention doesn't excuse you from labeling every bearing. A bearing without its explicit north-reference label is useless to anyone outside the agreement — the SAR team called in to help, the next group you hand off to, yourself a year later when you've forgotten what the convention was. A standing convention can dull your familiarity with the alternatives. When you never have to think about which north you're using, you're less likely to notice when a new compass or GPS arrives configured for a different reference. Always say which north The single most useful discipline you can develop: no bearing or heading is complete without the word True, Magnetic, or Grid following it. Don't make people guess — say it and write it. "Bearing 45°" is meaningless. "45° magnetic" or "45° grid" is unambiguous and self-documenting weeks later. This habit catches more downstream errors than any amount of formula drilling. Further reading on maptools.com North References tutorial — the three norths and how to use them Magnetic Declination Calculator — look up the current declination at any U.S. location and print a reference sheet for the field North References video, part 1 · part 2 · part 3 — short walkthroughs North References video, part 1 thumbnail: a globe in space with the rotation axis drawn through both poles and a yellow North Star above the North Pole, plus a sample route traced across the surface — frames the geometric setup for True North. North References video, part 2 thumbnail: a baseplate compass reading 56° M alongside a topo map and an enlarged angle diagram showing a 15° declination wedge between Magnetic North and Grid North with the bearing line at 56° M and the unknown grid bearing marked "?°" — the conversion problem. North References video, part 3 thumbnail: title card "Convert a bearing of 285° Grid to a magnetic bearing..." with three north lines (True, Grid, Magnetic) and small printed angles of 1.5° grid convergence and 16° declination — the worked Grid-to-Magnetic conversion example. North References on YouTube — companion video North Reference Sheet (PDF, instructors) — printable handout Do not teach this way Common student misconceptions

### Orienting Your Map
https://maptools.com/learn/orienting-your-map

What is orienting your map Orienting your map means turning it so its north points the same direction north points on the ground — so that north on the paper lines up with north in the world, east with east, and so on. Once the map is oriented, everything on it sits in the direction it really lies: the ridge drawn to the upper-left of your position is the ridge you'll actually see off to your upper-left. This is the first thing you do before you read a map in the field. An unoriented map is a puzzle — you have to mentally rotate it every time you ask "which way is that?" An oriented map answers directly. Orient the map before you try to locate yourself on it, before you pick a route, and before you take any bearing off it. There are two ways to orient: by matching what you see (terrain association) and by compass. Orienting by terrain association If you can see the country around you and recognize features on the map, you don't need anything but your eyes. Lay the map flat and rotate it until the pattern of roads, rivers, ridgelines, and other features on the paper lines up with the same features on the ground. As you turn the map, the shapes will suddenly "click" into place — the bend in the stream on the map points the same way as the bend you can see, the line of hills runs the same direction. When the patterns match in every direction you look, the map is oriented. This works best from a spot with a good view — a hilltop or open vantage where several recognizable features are visible. It's fast, needs no tools, and is the everyday method for following a map as you travel. It only fails when you can't see far enough or can't tie what you see to what's drawn — in fog, dense timber, or featureless terrain. That's when you reach for the compass. See Map Reading for recognizing features in the first place. Orienting by compass When you can't match terrain, use a compass to find north directly, then rotate the map to agree with it. The catch is that a compass points to magnetic north while the map is drawn to true or grid north, so the two don't line up by default — you have to account for the difference (declination). This is exactly the three-norths problem covered in North References (True, Magnetic, Grid) and Declination: set your compass for the local declination, or offset the map by that angle, so the compass needle and the map's north reference point the same way. Then turn the map until they agree, and it's oriented. See Compass Uses for the mechanics of the compass itself. Orienting yourself Orienting the map is half the job; the other half is knowing where on it you're standing. With the map oriented, look around and find features you can identify on both the ground and the paper. Often that's enough — if you're at the trail junction or the lake outlet that's drawn right there, you've placed yourself. When your spot isn't that obvious, there's a small catalog of techniques for fixing your position on the map, from sighting on a couple of distant landmarks to reading a GPS. Those belong on their own page; see Locating Yourself on the Map. The point for now: orienting the map comes first, because every method of finding yourself depends on the map already agreeing with the ground. Slides from John's Wilderness Navigation class Slides from John Carnes's 4.5-day Wilderness Navigation class (Friday evening + Saturday + Sunday × two weekends) that illuminate this concept. Useful as diagram references for your own presentations and for exercise handouts. The slides need a speaker — they're diagram-heavy, light on prose. The decks are split by class weekend: D1 is the first weekend's deck, D2 the second's. Orienting your Map 2 slides — D1 #441-442 Keynote: map-orientation.key PowerPoint: map-orientation.pptx Full-resolution diagrams (drop into your own deck) Slides (2): map-orientation slide #441 map-orientation slide #442 Orienting your Map — D2 opener 3 slides — D2 #46-48 These three slides are logically part of the map-orientation topic (per topic_map.yaml) but are still physically bundled inside John's "Orienting Yourself and Your Map" Keynote deck (D2 #46-62) — the next scripts/06_split_key_files.py run will move them into the map-orientation/ deck folder alongside D1 #441-442. The rest of that bundled deck now belongs to Locating Yourself on the Map and Alternate North-Finding Methods. Keynote: orienting-yourself-and-your-map.key PowerPoint: orienting-yourself-and-your-map.pptx Full-resolution diagrams (drop into your own deck) Slides (3): orienting-yourself-and-your-map slide #46 orienting-yourself-and-your-map slide #47 orienting-yourself-and-your-map slide #48 Attribution: Slide from John Carnes's "Wilderness Navigation" class, MapTools.

### Other Coordinate Systems
https://maptools.com/learn/other-coordinate-systems

This page is a catch-all for the location systems you'll meet beyond the big four — lat/lon, UTM, MGRS, and USNG. Two come up most often: other countries' national metric grids, and the Public Land Survey System, the land-description grid used across much of the United States. UTM isn't the only square metric grid UTM, MGRS, and USNG are the metric grids most people in the U.S. encounter, but they aren't the only ones. Many countries publish their own national grid: the British National Grid, the Irish Grid, and various UTM-like national systems across Europe and beyond. They all share the same basic idea — a square grid measured in meters, laid over a map projection, with easting and northing read off the grid lines. The practical takeaway: the skills you learned for UTM transfer. Identify the grid square, measure how far east and how far north your point sits inside it, combine that with the printed grid labels. The mechanics are the same; only the projection underneath and the labeling conventions differ. Why your MapTools ruler still works Here's the part that matters when you're standing over a foreign map: a MapTools grid tool, slot tool, or ruler reads in meters, so it works on any square metric grid — not just UTM. The tool doesn't know or care whether the grid lines belong to UTM, the British National Grid, or an Irish map. It only cares about one thing: The tool's scale must match the map's scale. If you have a 1:25,000 tool and a 1:25,000 map with a 1,000-meter grid, the tool reads that grid correctly regardless of which national system drew it. The 1,000-meter square on the British National Grid is the same physical size as a 1,000-meter UTM square, so the same marked edges measure it. This is why a single metric ruler at the right scale is so useful when you travel — see Map Scale for matching tool scale to map scale. What to watch for Three cautions when working with a non-UTM national grid: The numbers don't mean what UTM numbers mean. Eastings and northings are measured from that grid's own origin, not UTM's. Don't hand a British National Grid coordinate to someone expecting UTM — they'll plot it in the wrong place. Set your GPS to match the grid. To read or enter coordinates in one of these other square metric grids, change your GPS's coordinate (position) format to that grid system — British National Grid, Irish Grid, and the like are standard options on most receivers. With the format set to match, the numbers your GPS shows line up with the numbers printed on the map. For coordination across teams or borders, fall back to UTM or lat/lon. National grids are great for in-country navigation but aren't universal. When a coordinate has to cross from one team or country to another, convert it to UTM or latitude/longitude — the systems everyone agrees on. The catch: the map may force your hand. If your map is only printed with one grid, you have to work in the coordinate it shows — so match your tool and GPS to the map first, and convert for sharing second. Land descriptions: the PLSS Not every grid printed on a map is a position system. The Public Land Survey System — township, range, and section — divides much of the U.S. into one-mile squares to describe land, not to position it. Its red, center-numbered sections are easy to mistake for a coordinate grid, but they're the framework legal land descriptions are written against — they answer "how is this parcel described?" rather than "where am I?" See Public Land Survey System (PLSS) for how to read a legal land description and why it isn't a substitute for a metric coordinate.

### Plotting a Bearing on a Map
https://maptools.com/learn/plotting-a-bearing-with-a-compass

Plotting a bearing means drawing the bearing you measured in the field as a line on your map. A common use is locating yourself: you know you are somewhere along a feature (say, a lakeshore), you sight a bearing to a landmark you can identify on the map, and where the plotted line crosses the feature is your position. Because the bearing was taken from your unknown location toward a known landmark, you plot it starting at the known landmark and extend the line back toward yourself — a back bearing. Every bearing carries a north reference (Magnetic, Grid, or True). It is an integral part of the bearing — always say or write it (e.g. "60°M" for 60° Magnetic). Most maps are gridded to Grid North, so unless your compass or method handles it for you, you must convert a Magnetic bearing to the map's north reference before plotting. If north references are unfamiliar, study North References (True, Magnetic, Grid) and Declination first. A useful habit before plotting any bearing: identify roughly which of the eight compass points (N, NE, E, SE, S, SW, W, NW) the target lies in, and use that as a "reality check" as you work so an upside-down protractor or a sign error becomes obvious. Rough direction to the cabin landmark — a quick mental 'NE-ish' reality check before you plot With a Protractor A good navigation protractor is marked in single degrees, numbered clockwise, with parallel lines running along the 0°–180° axis so you can align it to the map's north reference lines. (Avoid quadrant-style drafting protractors numbered 0–90 four times.) See Compass Uses for choosing and reading the instrument. A good navigation protractor: single-degree marks numbered clockwise, with parallel lines along the 0°–180° axis In the worked example, the sighted bearing is 60° Magnetic and the map shows Magnetic North 5° east of Grid North, so we add 5° to plot a 65° Grid bearing. Declination diagram: Grid North vertical, Magnetic North 5° east of Grid North, bearing line at 60° from Magnetic North = 65° from Grid North, with the landmark at the bearing line's tip The scenario: a small lake; you are somewhere on the shoreline and have sighted a 60°M bearing to the cabin across the lake Convert the bearing to the map's north reference (here, 60°M + 5° = 65° Grid). Place the center point of the protractor on the known point (the landmark). Step 2: centering the protractor on the known point — the cabin Rotate the protractor until its 0°–180° lines are parallel to the north reference lines on the map. Step 3: rotating the protractor so its 0°–180° lines align with the map's north reference lines Make a small pencil mark at the edge of the protractor at the desired bearing value. Step 4: marking the map at the protractor's edge at 65° Grid Remove the protractor and use a straight edge to draw a line from the known point through your mark, extending it as a back bearing toward your unknown location. Step 5: extending the line as a back bearing from the cabin back across the lake Where that line crosses the feature you are on (the shoreline) is your location. Done: the back bearing crosses the shoreline at your location Thread technique: many MapTools protractor tools have a hole at the center. Loop a piece of thread (or thin elastic) through the hole, pull it tight across the bearing value on the edge, and use the taut thread as your bearing line — handy for extending a line farther than a short straight edge reaches. With a Baseplate Compass You can plot with an orienteering/baseplate compass without orienting the map and without using the magnetic needle at all — the rotating capsule acts as your protractor. This example again adds 5° to a 60° Magnetic sighting to get 65° Grid. Convert the bearing to the map's north reference and dial that value (65°) into the compass housing. Step 1: dialing 65° into the compass housing Set the compass on the map and rotate the whole compass until the capsule's meridian (orienting) lines are parallel to the map's north reference lines. The magnetic needle is ignored and may point anywhere; do not orient the map. Step 2: aligning the capsule's meridian lines with the map's north reference lines; the magnetic needle is ignored Keeping the capsule aligned to north, slide the compass so that one straight edge of the baseplate touches the known point. Step 3: sliding the compass so a baseplate edge touches the known point Draw the bearing line along that baseplate edge, extending it as a back bearing. Step 4: drawing the bearing line along the baseplate edge as a back bearing Where the line crosses your feature is your location. Done: the bearing line crosses the shoreline at your location Adjusting for Declination If your baseplate compass has a declination adjustment, you can set the Magnetic-to-Grid offset once and then plot directly in Grid degrees with no per-bearing math. Re-check the setting whenever you move to an area with different declination. Two adjustment styles: Gear-driven: a small screw on the bottom of the baseplate drives a gear that rotates the orienting arrow inside the capsule independently of the meridian lines. Adjusting 5° East moves the orienting arrow to point 5° east of north while the meridian lines stay put. Top view: orienting arrow rotated 5°E of the meridian lines Bottom view: the small adjustment screw and gear that drives the orienting arrow Friction-fit: the meridian lines are printed on the angular ring and the whole capsule turns, so the orienting arrow can't move on its own. This style is a bit harder to align to the map's north lines. Top view: the entire capsule rotated 5°E so the meridian lines now sit 5° off the angular ring Friction-fit adjustment: the capsule turns within the angular ring With the compass set for the local declination, the sighted bearing is read directly in the map's reference — here 65° Grid, no further conversion: Confirm the compass is adjusted for the local declination (e.g. 5° East). Dial the bearing (65°) into the housing. Because the compass is declination-set, no conversion is needed. Set the compass on the map and rotate it until the capsule's meridian lines are parallel to the map's north reference lines. The magnetic needle is not used and the map need not be oriented. Aligning the capsule's meridian lines with the map's north reference lines on a declination-set compass Slide a straight baseplate edge to the known point. Draw the bearing line along the edge and extend it as a back bearing to find your location. With a Lensatic Compass Lensatic compasses use a floating magnetic dial rather than a settable capsule, so plotting with one requires orienting the map to Magnetic North and using the compass's own dial. Their cards are typically marked in 5° and 10-mil increments; 5° is too coarse for good work, so sight and plot in mils (the example uses 1070 mils Magnetic). Because you plot relative to Magnetic North, no north-reference conversion is needed — but you do need an accurate magnetic north line on the map. A straight-edged lensatic compass — the magnetic dial sits on a pivot inside; one edge of the housing is a straight ruler Establish a Magnetic North reference line (do this once per map): do not trust the map's declination diagram — its angle is often drawn inaccurately and may be out of date. Instead, with a protractor aligned to True or Grid North (matching whatever reference your declination value is given in), mark the current declination angle and draw a labeled Magnetic North line with a straight edge. This line is good for many years. Why not to trust the map's printed declination diagram — the angle is often inaccurate or out of date Drawing your own Magnetic North reference line: use a protractor aligned to True or Grid North, mark the declination angle, then draw the line with a straight edge Metal warning: you are using the live magnetic dial, so keep metal away. Watch the work surface — wooden tables often hide screws and nails — and never plot on a vehicle's hood or tailgate. The anvil effect: hidden metal under the work surface deflects the magnetic dial Straight-edged lensatic Draw your Magnetic North reference line on the map (see above). Lay the straight edge of the compass along the Magnetic North line. Step 2: laying the compass's straight edge along the Magnetic North reference line Rotate the map and compass together as a unit until the magnetic dial reads north (the map is now oriented to Magnetic North). Step 3: rotating map and compass together as a unit until the dial reads north Without changing the map's orientation, slide the compass so its edge touches the known point and the dial reads your bearing (1070 mils). Step 4: sliding the compass so its edge touches the known point and the dial reads 1070 mils Draw the bearing line along the edge and extend it as a back bearing. Where it crosses your feature is your location. Done: the back bearing along the compass edge crosses the shoreline at your location Round lensatic A round lensatic compass has no straight edge. Use an imaginary line down its center — through the sighting wire and the dial's pivot. If the housing has alignment notches at each end of that line, use them; if not, add permanent notches (file, scratch, or marker) aligned with the sighting wire and pivot. A round lensatic compass — no straight edge; alignment runs through the sighting wire and the dial's pivot Drawing the Magnetic North reference line (same approach as for the straight-edged compass): protractor aligned to True or Grid North, mark the declination angle, draw the labeled line Draw your Magnetic North reference line on the map (see above). Align the compass's center line (notches) along the Magnetic North line. Step 2: aligning the round compass's center notches along the Magnetic North reference line Rotate the map and compass together as a unit until the magnetic dial reads north. Step 3: rotating map and compass together as a unit until the dial reads north Without changing the map's orientation, move the compass so the known point sits under the sighting wire and the dial reads your bearing (1070 mils). Step 4: moving the compass so the known point sits under the sighting wire and the dial reads 1070 mils Make a pencil mark at the far notch, then draw the bearing line through the known point and that mark with a straight edge, extending it as a back bearing. Done: the bearing line drawn through the known point and the far notch crosses the shoreline at your location After plotting any bearing, plot at least one more bearing to a different known landmark — where the lines intersect confirms your position and exposes errors. The careful map-orientation and metal precautions are why many people prefer plotting with a protractor tool such as a coordinate scale and protractor instead. More on maptools.com Original step-by-step tutorials, with photos and diagrams, for each method: Protractor: https://maptools.com/tutorials/plotting/protractor Baseplate compass: https://maptools.com/tutorials/plotting/compass Baseplate compass, declination-adjusted: https://maptools.com/tutorials/plotting/compass-declination Straight-edged lensatic: https://maptools.com/tutorials/plotting/straight-lensatic Round lensatic: https://maptools.com/tutorials/round-lensatic

### Public Land Survey System (PLSS)
https://maptools.com/learn/public-land-survey-system

What the PLSS is The Public Land Survey System is the grid that carves up most of the American West — and, in fact, most of the United States outside the original thirteen colonies. It's the system behind phrases like "the northeast quarter of Section 14, Township 2 North, Range 3 East." If you've seen a topo map with red one-mile squares numbered in their centers, that's the PLSS. It is a land-subdivision grid, designed in the 1780s to divide and sell public land in an orderly way — not a precise positioning system like a map coordinate. Knowing how to read it lets you connect a legal land description to a place on a topographic map. Township, range, and section The PLSS is built outward from surveyed reference lines: an east-west base line and a north-south principal meridian. From their intersection, the land is divided into a grid of squares roughly six miles on a side, called townships. Township locates a six-mile square north or south of the base line. "Township 2 North" (T2N) means the second row of squares north of the base line. Range locates that same square east or west of the principal meridian. "Range 3 East" (R3E) means the third column east of the meridian. Together, township and range pin down one six-mile square. That square is then divided into 36 sections, each one mile by one mile (640 acres). Sections are numbered 1 through 36 in a back-and-forth, boustrophedon pattern: starting at the northeast corner with Section 1, running west to Section 6, dropping down a row and running east to Section 12, and so on, ending with Section 36 in the southeast corner. Sections are subdivided further by quarters: the northeast quarter (NE¼), and quarters of quarters (the NE¼ of the SW¼), each step cutting the area to one-fourth. How to read a legal land description Legal descriptions read from the smallest unit to the largest. Take: NE¼ SW¼ Sec. 14, T2N R3E Read it inside-out: T2N R3E — find the township two rows north of the base line, three columns east of the principal meridian. That's your six-mile square. Sec. 14 — within that square, find section 14 (counting in the boustrophedon order). SW¼ — take the southwest quarter of that one-mile section. NE¼ — take the northeast quarter of that quarter — a 40-acre parcel. Each named principal meridian governs its own region, so a complete description also names the meridian (e.g., "Mount Diablo Meridian") to avoid ambiguity between regions that reuse the same township and range numbers. How it relates to metric map coordinates The PLSS and a metric grid like UTM both put squares on a map, which is exactly why beginners confuse them — but they answer different questions: The PLSS is the framework legal land descriptions are built on. Its squares are one mile on a side, traditionally printed in red, numbered in their centers. It gives you a standardized way to describe a parcel — the grid that property boundaries are written against, not a record of who owns what. A metric coordinate grid describes position. Its squares are typically one kilometer on a side, and it tells you where a place is to within a few meters. The PLSS is far less precise — a section is a full square mile — and its lines don't line up cleanly with lines of Latitude and Longitude. The system was laid out by small survey crews working their way across the frontier with transits and measuring chains, fitting a flat grid onto a curved Earth across terrain that fought them the whole way. Plenty of errors crept in, and the harder the country, the wilder the lines. But because the land was divided, sold, and monumented on the ground from those surveys, the errors are baked in permanently: the section corners those crews set are the boundaries, mistakes and all. That's why what was planned as neat one-mile squares is full of irregularities. Use the PLSS to interpret a legal description, locate a mining claim, or talk land with a rancher. Use a metric grid or lat/lon when you need to navigate to a point. They coexist on the same map; just don't read one as the other. Section corners on the ground Those section corners aren't just lines on a map — on public land, many are marked by a physical monument: a brass cap on a post or pipe, a stone, or a marked tree, set where the original survey put the corner. If you find one, you've pinned your location exactly. The map shows you which corner it is — read the section, township, and range off the surrounding grid — and now you know precisely where you're standing, no instrument required. Worth knowing when you're moving through PLSS country: a found monument is a free, unambiguous fix. Where it applies The PLSS covers about thirty states — most of the West and Midwest. It does not cover Texas, the original colonies, or other areas surveyed under earlier metes-and-bounds systems. If your map shows numbered one-mile sections, you're in PLSS country.

### Reading and Plotting UTM Coordinates with MapTools Tools
https://maptools.com/learn/plotting-utm-with-maptools-tools

These tools let you read and plot UTM Coordinates on a paper map with more precision than the printed grid lines alone allow. Each printed grid line is labeled with its Easting or Northing in meters; a plotting tool adds the distance from the nearest grid line to your feature. Add the two together and you have a full UTM coordinate. The five form-factors below — grid style tool, slot style tool, corner ruler roamer, mini corner style tool, and map ruler — all do the same job in slightly different ways. The grid style tool reads to 100m precision; the other four reach 10m precision on a 1:24,000 map. Before using any of them, confirm your map's scale matches the tool's scale and that you know which UTM zone you are working in. Most USGS topo maps print a UTM grid at 1,000m spacing, though 10,000m and 100m grids also exist. Always read the Easting first, then the Northing. A complete UTM coordinate A complete UTM coordinate has three parts: a zone designator, an Easting in meters, and a Northing in meters — for example, Zone 10S, 706832mE, 4344683mN. The zone comes from the map's marginalia. The Easting and Northing — with all their digits — come from the printed grid labels plus the additional precision your plotting tool resolves. On a GPS receiver set to display position in UTM, the same three components appear: GPS receiver displaying a UTM coordinate Reading and plotting All five tools work in either direction. The procedures below walk through the read direction — start with a feature on the map, end with its coordinates. Plotting (start with coordinates, end with a mark on the map) is the same procedure run in reverse: To read: measure the Easting and Northing offsets from the western and southern grid lines, then add each offset to the corresponding grid-line label to get the full coordinate. To plot: subtract the grid-line labels from the target Easting and Northing to get the offsets you need, position the tool so those offsets land on the grid lines, then mark where the tool indicates the target — at its corner, in its slot, or at the right tic on its scale, depending on which tool you're using. The Corner Ruler Roamer section spells the plot direction out explicitly; the other tools work the same way in reverse. The worked example The five sections that follow all use the same illustrated point — the same Zone 10S, 706832mE, 4344683mN as the GPS display above — so you can compare how each tool truncates the reading to its native precision. In every case the feature sits in the 1km grid square bounded on the west by 706000mE and on the south by 4344000mN; the precise offset of the feature within that square is 832m east and 683m north. UTM Grid Style Tool A grid style tool is a transparent square ruled into a fine grid — 100m divisions for a 1:24,000-scale tool — that you align with the printed UTM grid lines and read the offset directly off its own scales. For many land-navigation situations, 100m precision is plenty. Identify the grid line just west of your feature and the grid line just south of it, and read their Easting and Northing values from the map's grid labels. In the illustration the western grid line is 706000mE and the southern grid line is 4344000mN. Place the tool over the grid so its edges line up with those two printed grid lines. Read the Easting offset along the tool's bottom edge — the number of 100m divisions east of the western grid line to your feature. In the illustration the feature sits between the 8 and 9 marks; truncated to 100m, the offset is 800m E. Read the Northing offset along the tool's left edge the same way. The feature sits between the 6 and 7 marks, so the offset truncates to 600m N. Add each offset to its grid-line value: Zone 10S, 706800mE, 4344600mN — 706000 + 800 east of zone 10's central meridian, 4344000 + 600 north of the equator. UTM Grid Style Tool aligned on the 1km grid square UTM Slot Style Tool A slot style tool has a horizontal base ruler that sits along the southern grid line and a vertical slot — with a fine-divisioned north-south ruler — that slides east and west to bracket the target. On a 1:24,000-scale tool, both rulers give you 10m precision. Position the base of the tool on the southern grid line of the square containing your feature. In the illustration that's 4344000mN. Slide the tool east–west until the target is centered in the vertical slot. Read the Easting value of the western grid line from the map's grid labels — 706000mE in the illustration. Read the Easting offset where the base ruler crosses the western grid line. The feature's offset truncates to 830m E, giving a full Easting of 706830mE. Read the Northing offset where the vertical ruler in the slot crosses the target. The offset truncates to 680m N, giving a full Northing of 4344680mN. The feature is at Zone 10S, 706830mE, 4344680mN. UTM Slot Style Tool bracketing the example position UTM Corner Ruler Roamer A corner ruler roamer is a baseplate-style tool (with a compass-rose protractor on most models) carrying a UTM corner ruler. The corner sits on your feature, with two perpendicular rulers extending west and south — far enough to cross the western and southern grid lines of the square. At a 1:24,000 scale it reads to 10m precision. To read a feature's coordinates, place the corner of the ruler exactly on the feature, with the two ruler edges extending west and south. Read the Easting value of the western grid line from the map (706000mE in the illustration). Read the Easting offset where the west-extending ruler crosses that grid line — 830m E in the illustration. Read the Northing value of the southern grid line (4344000mN). Read the Northing offset where the south-extending ruler crosses that grid line — 680m N. Add each offset to its grid-line value: Zone 10S, 706830mE, 4344680mN. To plot a known coordinate, position the corner so the offsets you want line up with the grid lines, then mark the map at the corner. If the grid square sits on the edge of your map and there is no room to the west or south, start from a different corner. The method still works — just remember that UTM values increase from west to east and from south to north. UTM Corner Ruler Roamer on the example position Field expedient: if you are on an odd-scaled map or left your tools behind, you can build a quick corner ruler from a scrap of paper. Use the map's metric scale bar to mark off one kilometer and the 100m subdivisions along one edge, repeat along the other edge of the corner, and number both scales starting from zero at the corner. Building a field-expedient corner ruler from a scrap of paper UTM Mini Corner Style Tool A mini corner style tool is a compact triangular ruler — same operating principle as the corner ruler roamer, smaller and lighter. The right-angle corner sits on the feature with the two scale edges extending west and south. On a 1:24,000-scale tool, 10m precision. Place the right-angle corner exactly on the feature, with one ruler edge extending west to (or past) the western grid line and the other extending south to the southern grid line. Read the Easting offset where the west-extending edge crosses the western grid line — 830m E in the illustration. The full Easting is 706000 + 830 = 706830mE. Read the Northing offset where the south-extending edge crosses the southern grid line — 680m N. The full Northing is 4344000 + 680 = 4344680mN. The feature is at Zone 10S, 706830mE, 4344680mN. UTM Mini Corner Style Tool on the example position UTM Map Ruler A map ruler is a straightedge marked with a metric distance scale — 10m tic intervals on a 1:24,000-scale ruler. There is nothing UTM-specific about it at all: you are simply measuring two distances in meters, which is exactly what a UTM Easting and Northing are. Use the ruler twice per coordinate — once for the Easting, once for the Northing — at 10m precision on a 1:24,000 map. For the Easting, lay the ruler horizontally inside the grid square at the feature's north-south position, with the 0m mark on the western grid line and the scale extending east. Read where the feature falls on the scale — 830m E in the illustration. Add to the western grid line: 706000 + 830 = 706830mE. For the Northing, lay the ruler vertically inside the grid square at the feature's east-west position, with the 0m mark on the southern grid line and the scale extending north. Read where the feature falls — 680m N in the illustration. Add to the southern grid line: 4344000 + 680 = 4344680mN. The feature is at Zone 10S, 706830mE, 4344680mN. UTM Map Ruler measuring the Easting and Northing offsets Further reading on maptools.com All five tool styles are made for several different map scales. The original step-by-step tutorials and additional background are on maptools.com: Quick guide to UTM coordinates: https://maptools.com/tutorials/utm/quick_guide Grid overlay tutorial: https://maptools.com/tutorials/utm/grid_tools Corner ruler tutorial: https://maptools.com/tutorials/utm/corner_tools Slot tool tutorial: https://maptools.com/tutorials/utm/slot_tools

### Route Planning and Following
https://maptools.com/learn/route-planning-and-following

What route planning and following are Route planning is choosing the path you intend to walk before you start walking it. Route following is executing that plan once you're on the ground. The two are tightly coupled: how you plan a route depends on how you intend to follow it, and how you follow a route is shaped by the choices you made when you planned it. For that reason planning and following are treated as a single topic. The work of route planning is not drawing a line on the map between where you are and where you want to be. It's building a navigation story: a sequence of legs joined by recognizable points on the ground, with deliberate choices about which terrain to use as your guide, what you'll see along the way that confirms you're still on plan, and what you'll do when the plan doesn't survive contact with the weather. The work of route following is then largely about reading the story you wrote, watching for the features you said you'd see, and noticing — early — when what you're seeing doesn't match what you planned. Almost everything that follows is vocabulary and technique for doing those two things well. Two reasons to follow a route Before planning a route, be clear about which of these two problems you're solving — they call for very different plans. You need to reach the destination. You may not care much about being on the planned line; another acceptable line is fine if the terrain offers one. Most recreational hiking is in this category. You need to travel close to the planned line. Hazards on either side (cliffs, private land, avalanche terrain, a closed wilderness boundary), or a project goal that defines the route itself (a survey transect, a search pattern, a specific traverse you came to do). The second case is the more demanding one. It requires a tighter plan, more attention to off-line drift, and — almost always — a preprogrammed GPS route to tell you when you've drifted, since a compass bearing tells you which direction to walk but not whether you're still on the line. Factors that drive the plan The route you plan is the product of trade-offs among several factors. Different trips weight them differently; the planner's job is to be honest about which ones matter on this trip. Hazards to avoid. Cliffs, water crossings, avalanche terrain, hunting zones in season, private property. Destination and schedule. Where you need to be, by when. Difficult terrain and vegetation. Boulder fields, dense brush, blowdown, deep snow, marshland. These don't show up as obstacles on a paper map the way a cliff does, but they can turn a 2 km leg into a 4-hour ordeal. Fastest, shortest, easiest — they are rarely the same line. Shortest is the straight line. Fastest usually follows the trail network or the easiest terrain. Easiest minimizes elevation gain, route-finding difficulty, and physical work. Pick which one you actually want. Area coverage or avoidance. Sometimes the point of the route is the line, not the endpoints — surveys, search patterns, a deliberate scenic detour, a deliberate avoidance of someone else's camp. On-trail versus off-trail A trail almost always beats a straight line. A trail at 1.5x to 2x the straight-line distance is an easy trade in most conditions — easier walking, faster pace, no route-finding load, and the trail itself does the job of a handrail for you. Difficult cross-country conditions push that ratio higher: in dense brush or steep loose talus, a 3x detour on trail can still be the faster option. The corollary is that an off-trail route is a deliberate choice. It needs a reason: there's no trail, the trail doesn't go where you're going, or the off-trail line is meaningfully shorter or more scenic. "It looked shorter on the map" is rarely a reason that holds up on the ground. Time factors Many a trip has turned into a disaster because a pressing need to be back in time didn't survive a route that took longer than planned. If you have to be back on time, leave extra time for the unexpected. A flat tire at the trailhead, a stream higher than expected, a wrong turn that costs forty minutes — these are the normal events of a backcountry day, not exceptional ones. Plan for them. Build bailout possibilities into the plan, and decide in advance when to use them. These are choice points: places on the route where, before you started, you wrote down what would cause you to take the bailout instead of continuing. Deciding that on the ground, tired and behind schedule, is much harder than deciding it the night before. The drive home is often the most dangerous part of the trip. You're tired, possibly under-slept, on a long winding road out of the mountains, usually in late afternoon or after dark. The route plan that ends at the trailhead is incomplete; the plan that ends in your driveway is the real one. Build the drive into the schedule, and into the bailout logic. Building a navigation story The route on a map is a line. The route in your head should be a story: a sequence of named, recognizable pieces you'll narrate to yourself as you walk it. The components: Legs. Discrete sections of travel between two recognizable points. A leg is short enough that you can keep yourself oriented on it without needing a fix in the middle. In good conditions on familiar terrain, a leg can be kilometers long. In poor visibility, a leg should usually be 500 m or less — short enough that small navigation errors don't compound into large ones before the next checkpoint. Checkpoints. Places along the leg where you expect to be able to confirm "I am here, on plan." A trail junction, a stream crossing, the corner of a forest, the top of a rise. Checkpoints are confidence-builders. A plan with checkpoints every few hundred meters tells you quickly when something has gone wrong; a plan with no checkpoints between the trailhead and the summit tells you only after you've already drifted a long way. Course-change points. Places where the plan calls for you to change direction or transition between travel modes (off the trail onto a bearing, off a bearing onto a handrail). These are the points where errors creep in — easy to miss in poor visibility, easy to misidentify in unfamiliar terrain — so they deserve extra attention in the plan. Good practice: position each course-change point at a feature that's not just on the map but is unmistakable on the ground. A nondescript bend in a contour line is a bad course-change point; a clear trail junction or a stream confluence is a good one. Choice points. Places where the plan has options, and where you decide between them based on conditions. "If we reach the saddle by 1:00 PM, continue to the summit; otherwise turn back here." Writing the choice down in advance — with the specific condition that triggers it — is what makes it real. A vague intention to "see how we feel at the saddle" is not a choice point. A useful self-check during planning: if you can't narrate the route out loud as a sequence of "first I'll do this until I reach that, then I'll turn and do this other thing until..." you haven't planned it yet — you've drawn a line. Linear features: the planner's primary tool Most of route planning, once you've decided roughly where to go, comes down to identifying linear features and using them. There are three categories, ordered roughly from easiest to follow to hardest. Man-made linear features Roads, trails, fences, power lines, walls. These are the easiest to follow — they're designed to be linear and visible, and most are explicitly marked on the map. When the map shows a trail going where you want to go, the planning problem is largely solved. Natural linear features Rivers, creeks, shorelines, vegetation transitions (forest edge to grass, treeline). These are nearly as good as man-made features, sometimes better — a river is rarely obscured by snow the way a faint trail is. Vegetation transitions in particular are underused; a clear forest edge running across your direction of travel is one of the most reliable features you can navigate to. Terrain breaks as linear features The line where slope angle or direction changes obviously — the top of a steep section, the bottom of a slope where it meets the flats, the ridgeline, the bottom of a drainage. These don't appear on the map as drawn lines; you have to read them out of the contour pattern. But they're often the only good linear features in terrain that has no streams and no trails, and they don't disappear under snow. A planner who can only see man-made linear features is limited to roads and trails. A planner who can read terrain breaks out of contour lines has access to a much larger and more durable network. Handrails A handrail is a linear feature along your direction of travel that you can see and follow. It does most of the work of keeping you on route; your job is mostly to walk alongside it. When you hike on a trail, you're using the trail as a handrail. The skill that opens up the rest of the backcountry is learning to use terrain features as handrails in the same way: walking along the edge of a meadow, along the base of a cliff band, along a contour at the top of a steep section, along a stream. The criteria for a good handrail: It runs roughly in your direction of travel for the length of the leg you want to use it for. It's continuously visible — you can see it from where you're standing, and you can keep seeing it as you walk. It's unambiguous on the map, so you know where along it you are. Even an invisible compass bearing is technically a handrail, but it's a harder one to follow because it requires constant compass attention. A visible handrail lets you put the map and compass away and just walk. When you don't have a handrail When no good handrail runs your way, the alternatives, roughly in order of ease: Hike toward something you can see. A peak, a tower, a notch on the skyline — anything you can identify on both the ground and the map. This is the simplest possible navigation: keep walking toward the thing. Hike along a compass bearing or in a general direction. Less accurate than a visible target, but works when nothing is visible. Hike along a contour. Hold your elevation, walk around the hill. Without some kind of aid, most people walking on a contour will drift slowly downhill — gravity is patient. An altimeter helps. The honest warning that goes with all of these: without something to reference against, people walk in arcs that eventually close into circles. This is well documented and surprisingly hard to overcome with willpower alone. The compass, the visible target, the altimeter, or the handrail are how you avoid it. Without them, on featureless terrain in poor visibility, you will end up where you started. Catching features A catching feature is a linear feature perpendicular to your direction of travel — something you're going to walk across whether you mean to or not. It's the navigational equivalent of a backstop. Catching features are what you use to signal a course-change point or to confirm you've gone far enough. "Walk west until you hit the road" works because the road is a catching feature: it doesn't matter exactly which point on the road you reach, what matters is that you'll know unambiguously when you've reached it. Good catching features are large, obvious, and continuous across your line of approach. A road, a major stream, a ridgeline running perpendicular to your travel, a forest edge running across your path. Aiming off (deliberate course offset) The standard mistake: you walk a bearing toward a stream junction, you reach the stream, the junction isn't visible, and now you don't know whether to turn upstream or downstream. The fix is deliberate course offset — also called aiming off. Instead of aiming straight for the junction, aim deliberately to one side of it by an amount larger than your expected error. When you reach the stream, you know which way to turn. The general technique works any time your destination lies on or near a linear catching feature. Aim to a known side of it; let the catching feature backstop you; turn the right way when you arrive. Plan on errors of roughly: ±5° for casual travel — about ±100 m of cross-track error per kilometer of bearing. ±2° for careful travel — about ±40 m per kilometer. Those numbers tell you how far off-line to deliberately aim. If you're walking 2 km to a junction at casual accuracy, you might be ±200 m off the line when you arrive — so aim at least 300 m to one side. If the offset you'd need is larger than the catching feature is long, the catching feature isn't good enough; pick a different one or shorten the leg. Attack points An attack point is something easy to find that's near something hard to find. The technique: navigate easily to the attack point, then do the detailed, careful navigation from there. For a route to a small unmarked feature — a campsite in dense forest, a specific boulder, a cave entrance — the direct line is often a bad plan. Any error compounds across the whole distance, and the target gives you no help finding it once you're close. But if there's an obvious, easy-to-find feature within a few hundred meters — a trail junction, a distinct lake outlet, a named summit — you can navigate to that with confidence, and only then switch to careful bearing-and-pace work for the final approach. The rule of thumb: a good attack point is within about 500 m of your real target, easy to reach, and instantly recognizable on the ground. When you don't have a good catching feature When the terrain offers no useful linear feature to backstop the end of your leg, the alternatives: Use time to estimate distance. If you know how long it takes you to walk a kilometer under current conditions, you can use elapsed time to know when you've arrived. (See the timing section.) Count paces. Slower than timing, but more accurate over short legs. Use an altimeter and choose a catching elevation. The elevation contour itself becomes the perpendicular feature you're catching against — works particularly well on sloped terrain. Take a bearing on a distant object and walk toward it. Use the visual alignment of two known objects. When two features on the map line up visually, you're on the line between them. These are all weaker than a real linear catching feature. If you find yourself using two or three of them on the same leg, the leg is probably too long. Estimating time and distance You need a working sense of how long a leg takes so you can plan, so you can pace yourself, and so you can use time as a substitute for a catching feature when nothing else is available. The best estimate is one you've calibrated to yourself under current conditions: Time how long it takes you to walk a measured kilometer on the kind of terrain you're on, with the pack you're carrying. Use that figure until conditions change enough to warrant a new measurement. Until you have your own figures, a reasonable starting point: 15–20 minutes per kilometer on reasonable terrain, plus 2 minutes per 40 ft of elevation gain. That's a serviceable estimate for adult hiking pace with a day pack; adjust upward for heavier loads, deep snow, dense brush, or larger groups. A standard pitfall: estimates made at the kitchen table are almost always optimistic. The leg that took 22 minutes in October on a dry trail will take 45 minutes in February on the same trail under a foot of snow. Bailout features A bailout feature is something large and unambiguous that you can navigate to if the plan falls apart — typically without needing a map or compass to find it. The classic form is a general direction of travel that eventually leads to safety: "Go west and downhill, you'll eventually reach State Highway 1." That's a bailout. It doesn't require precise navigation. It only requires that you can tell which way is downhill, which way is west, and that you keep going long enough. Good bailout features in most settings: Major roads. Shorelines (ocean, large lake). City limits, a populated valley, a power line corridor. Sometimes a major river, with caveats — see the warning about gullies that follows. When you plan a trip, identify the bailout direction before you go. "If everything goes wrong, head [direction] and you'll hit [feature]." If you can't answer that question for the terrain you're planning to enter, you don't have a complete plan. A specific warning: streams and gullies are tempting bailout routes but often bad ones. They look like obvious downhill handrails on the map, and water does take the line of least resistance — but it does so vertically. A drainage that looks gentle on the contour map may contain waterfalls, cliffs, or impassable choke points that don't show up at the map's contour interval. If the drainage runs through a stretch of closely spaced contour lines, expect trouble. Following a route in poor conditions Darkness, fog, snow, whiteout — the conditions that make route-finding hardest are the same ones that make it most necessary. The problems compound: You can't see the hazards you planned to avoid. You can't see the checkpoints and handrails that would otherwise tell you you're on plan. You're not sure when you'll recognize the catching features or course-change points that the plan depends on — and you're afraid of missing them. What to do: Pick very distinct handrails. Large terrain breaks. Well-defined trails. Major streams. Things that won't disappear because of the conditions — and in particular, things that aren't buried under snow. Pick hugely obvious catching features. Roads, major valleys, ridgelines. Not subtle ones. Shorten legs. Errors compound over distance, and your error rate is higher in poor visibility. Legs of 500 m or less are reasonable in heavy fog or whiteout. Plan for larger errors. If you'd normally aim off by 100 m, aim off by 300 m. If you'd normally use ±5° as your casual accuracy, plan as if it's ±10°. Use a GPS. This is what GPS is best at. Make waypoints for every course-change point and choice point. On long legs, put intermediate "on-route" waypoints to reinforce your confidence that you're still on plan. The GPS doesn't replace your map-and-compass plan — it confirms it. A planning principle worth stating directly: the same route is two different routes in good and poor visibility. A line that works well in clear weather, using line-of-sight to a distant peak as a handrail, may have no usable handrails at all in fog. If there's any chance the conditions will turn, plan the route that works under the worse conditions. References Kevin Walker, Mountain and Moorland Navigation (Pesda Press, 2016), ISBN 978-1-906095-56-7 — the attack-point, handrail, and aiming-off vocabulary here draws on Part 3, Additional Techniques.

### USGS Topographic Maps
https://maptools.com/learn/usgs-topographic-maps

The standard U.S. topographic map The U.S. Geological Survey publishes the standard topographic coverage of the country, and for decades that has been the map most American land navigators learn on. Each sheet covers a quadrangle — a rectangle bounded by lines of latitude and longitude — which is why the sheets are called "quads." The workhorse is the 7.5-minute quad printed at 1:24,000: one sheet spans 7.5 minutes of latitude and 7.5 minutes of longitude, and at that scale it's detailed enough to show individual creeks, switchbacks, buildings, and contour lines. This is the deep dive on the USGS series specifically; for the broader survey of map kinds, see Map Types. What makes a USGS quad worth knowing is that it carries everything you need to use it with a compass and a GPS, printed right on the sheet. You just have to know where to look in the margin. The map collar The blank border around a USGS quad — the collar or margin — is not decoration. It holds the reference information that turns the printed picture into a tool you can navigate with: Quad name and adjoining sheets. The name is printed in the corners, and the names of the eight neighboring quads are noted around the edges so you can find the next sheet over. Scale and bar scales. The ratio (1:24,000 on a standard 7.5' quad) plus printed bar scales in feet, miles, and meters. The bar scale is the one to trust if the sheet has been photocopied or resized — see Map Scale. Contour interval. The constant vertical distance between contour lines, stated near the scale. See Map Reading for reading contours. Declination diagram. The angle between true north, magnetic north, and grid north for the sheet's location and date. See Map Reading. Datum. The earth model the coordinates are based on — modern quads use NAD 83, but many older sheets use NAD 27. This is the one to check before you match the map to your GPS; see Map Datums. Index map and revision history. A small locator map and the survey/revision dates. Maps go stale, so the date matters. Collar details from a sample 7.5' quad (Sharktooth Peak, CA): Quad name and series info printed in the map's corner Quad name and series info, printed in the map's corner. Bar scale in feet, miles, and meters, with the contour interval printed just below it Bar scale in feet, miles, and meters, with the contour interval printed just below it. Declination diagram showing true north, magnetic north, and grid north for this sheet and date Declination diagram — true north, magnetic north, and grid north for this sheet and date. Datum statement and UTM zone, showing both the current NAD 83 value and the superseded NAD 27 value for the same corner Datum statement and UTM zone, showing both the current NAD 83 value and the superseded NAD 27 value for the same corner. Index map locating the quad within the state Index map locating the quad within the state. Revision history and survey control notes Revision history and survey control notes. Coordinate grids on the quad USGS large-scale maps are friendly to whatever coordinate system you prefer, but they don't all print the grid the same way. UTM. Some quads print the full 1km UTM grid as thin black lines. Many others print only short blue tic marks along the edges marking where the grid lines would fall — you connect them yourself with a straightedge. Tic labels are sometimes the full coordinate in meters and sometimes abbreviated (the right-most three digits dropped on a 1,000m grid), with the full value spelled out in two or more corners. Lat/lon. The neat lines of Latitude and Longitude are usually not drawn across the face either. Instead, ticks sit on the edges and small crosses sit in the interior at 2.5-minute spacing; you draw the lines by connecting an edge tick to the matching interior cross. UTM grid tic mark with an abbreviated coordinate label UTM grid tic mark with an abbreviated coordinate label. Interior lat/lon cross mark at 2.5-minute spacing Interior lat/lon cross mark at 2.5-minute spacing. Don't confuse either of these with the Public Land Survey System section lines you'll see in the western states — those nominally one-square-mile sections are oriented to true north and numbered 1 to 36, and inexperienced users sometimes mistake them for the UTM grid. See Public Land Survey System (PLSS). Series and scales The 7.5-minute 1:24,000 quad is the one most people mean by "a USGS topo," but it isn't the only series. Older and broader coverage exists at 1:62,500 (the 15-minute series, which typically carries 1km UTM tics) and 1:100,000, each trading detail for the amount of ground on one sheet. When you pick a sheet, you're trading detail against coverage — the larger-scale 1:24,000 shows the most ground detail over the smallest area. USGS 7.5 minute, 1:24,000 topographic map USGS 7.5 minute, 1:24,000 topographic map. USGS 15 minute, 1:62,500 topographic map USGS 15 minute, 1:62,500 topographic map. USGS 30 minute x 1 degree, 1:100,000 topographic map USGS 30 minute x 1 degree, 1:100,000 topographic map. Where to get them The paper 7.5-minute quad described above is now largely a historical artifact. USGS discontinued the traditional topographic mapping program, and print distributors have mostly exited — for most areas, tracking down an actual old-style paper quad is hard. The realistic modern picture is different enough that it's worth walking through separately. The current USGS product: US Topo The USGS map store (store.usgs.gov) still sells current-coverage topographic sheets — as of June 2026, around $15 per printed sheet, or free as a PDF download. But the US Topo product is a different kind of map than the classic quad: instead of contours and cartographic symbols on a bare white base, the data is overlaid on an orthorectified aerial photograph. If you're used to the traditional look, it reads as strange — the same information is there, but the visual language is completely different. SE corner of a sample US Topo PDF, contours and grid over an orthorectified aerial photo SE corner of a sample US Topo PDF — contour lines and grid overlaid on an orthorectified aerial photo, instead of the traditional bare cartographic base. The PDF's page size is 24" × 29" — larger than any standard home or small-office printer handles in one piece, so printing it yourself at native size means a large-format printer or a print shop. Practical paper-map sources today For most people who actually want a printed paper topo in hand, USGS's own distribution isn't the practical path anymore. CalTopo (caltopo.com) has effectively become the default: you pick your own area and your own scale — nothing forces 1:24,000 — and print or order a sheet with the classic-style cartographic rendering. MyTopo (mytopo.com) is a similar commercial print-on-demand option in the same space. Either is a more realistic recommendation than "go buy a USGS quad." The USGS National Map Viewer (apps.nationalmap.gov) is the official live source if you want to pull current USGS data yourself or generate a custom US Topo PDF for an arbitrary area. Worth knowing it exists, but it's not the easiest way to get a map with traditional-style coordinate grids and collar labeling — the viewer is built for GIS-style data access first, readable field-map output second. Whichever route you take, check the collar (or its equivalent) of the final sheet for its scale, datum, and grids before you rely on it in the field.

### USNG Coordinates
https://maptools.com/learn/usng-coordinates

What USNG is For a hands-on, illustrated walkthrough of reading and writing USNG, the MapTools tutorial USNG Quick Guide covers the same ground as this page in a more visual format. USNG — the U.S. National Grid — is the civilian U.S. packaging of the same underlying UTM grid that the military uses as MGRS. A complete USNG coordinate looks like: 10S GJ 06832 44683 Handheld GPS receiver displaying the USNG position 10S GJ 06832 44683 Five parts, identical in structure to MGRS: 10S — Grid Zone Designation. The UTM zone number plus the latitude band letter. Necessary to make the coordinate unique over the entire globe. GJ — 100,000-meter Square ID. Two letters identifying a unique 100km square within the grid zone. 06832 — Easting. East-west position within the 100km square, in meters. The first two digits come from the western grid line label; the last three are the meters east of that line. 44683 — Northing. North-south position within the 100km square, in meters. Same logic against the southern grid line. Topographic map with the example USNG position marked, showing how each part of 10S GJ 06832 44683 maps to the Grid Zone Designation, 100,000m Square ID, and the easting and northing read off the grid The same map grid lines are used for both USNG and MGRS positions; only the writing convention and the datum handling differ. The grid lines on a 1:24,000-scale USGS quad are 1,000 meters apart, and each is labeled with its UTM easting or northing along the map edge: Close-up of a USGS quad's bottom-edge grid labels, showing the small-type "706" leading digit alongside the large-type "000mE" thousands-of-meters labels used to read the easting Precision through truncation USNG carries precision in the digit count, the same way MGRS does: Form Precision 10S GJ 06832 44683 1 m 10S GJ 0683 4468 10 m 10S GJ 068 446 100 m 10S GJ 06 44 1 km 10S GJ 0 4 10 km When using less precise representation, it is important to truncate rather than round the Easting and Northing values. The Easting and Northing always refer to the southwest corner of the grid square. USNG specifically recommends at least two digits per axis — so the smallest USNG-permitted area is a 10,000m square (10S GJ 0 4). MGRS allows reference to a full 100km square by letters alone (10S GJ); USNG doesn't. Differences from MGRS For students plotting on a topo map, the two systems behave identically. The differences only appear at the edges: Datum handling under NAD 27 Both systems default to WGS 84 (USNG also explicitly accepts NAD 83 as equivalent). They diverge when applied to the NAD 27 datum, which many older USGS topographic maps still use: MGRS shifts the second letter of the 100km square ID by ten letters, with no formal way to specify which datum the coordinate refers to. USNG does not shift letters but requires the datum to be specified alongside the coordinate. Same physical point under NAD 27: MGRS (NAD 27): 10S GU 0706832 4344683 USNG (NAD 27): 10S GJ 0706832 4344683 (NAD 27) This is a real distinction for users of older USGS maps. See Map Datums for the broader datum story. Geographic scope USNG is only defined for use "over all areas of the United States including outlying territories and possessions." That bounded scope is why the standard avoids some of the complications that MGRS has to address — for instance, USNG doesn't need to define the UPS coordinate system for polar regions. A USNG coordinate is always a U.S. coordinate. Truncation philosophy MGRS allows reference to an entire 100,000m square (10S EH). USNG suggests a minimum of two digits per axis. Not a hard prohibition — "the USNG does not specifically prohibit 100,000m truncation, but instead omits it from the standard document." Writing and saying it USNG is "formally written as an entity without spaces, parentheses, dashes, or decimal points." For human use, do the opposite: I would encourage you to use spaces when writing USNG coordinate strings, and to pause briefly between logical parts when communicating USNG coordinate strings verbally. If everyone you're working with is in the same 100km square, USNG (like MGRS) lets you drop the Grid Zone Designator and the 100km square ID and just exchange the easting and northing. Useful within a small operating area; dangerous at the boundaries. Who uses it The U.S. National Grid was promoted by the Federal Geographic Data Committee as a clean civilian standard for emergency response, FEMA coordination, search-and-rescue, and inter-agency disaster response. Anyone who reads MGRS can read USNG and vice versa, so the practical question is which one your peers use: FEMA-issued maps and disaster-response coordinates are the most common place a civilian sees USNG. Some U.S. national parks have begun overprinting USNG grids on their maps. Civilian SAR teams trained under FGDC standards use USNG. Outside those contexts — recreational hiking, private hunting, foreign navigation — you'll more often see UTM, lat/lon, or MGRS. Common errors It is easy to make a mistake using truncated position formats. Slipping a digit left or right results in a very different position. Worse, there is no visual clue that an error has been made until the coordinate is plotted. Same failure mode as MGRS: digit slips are silent. Read the coordinate back. Plot it on the map and confirm the location is plausible before acting on it. Choosing a coordinate system For guidance on when to use USNG vs. lat/lon vs. UTM vs. MGRS, see Selecting a Coordinate System. Further reading on maptools.com Interactive UTM Tutorial — the animated tutorial set to USNG, working a coordinate a step at a time on a real topo map. Shows the spaced USNG component formatting and the datum tag as they are actually written out. MGRS vs USNG Differences — how MGRS and USNG diverge on datum handling FGDC USNG Standard (PDF) — the federal standards document defining USNG Common student misconceptions

### UTM Coordinates
https://maptools.com/learn/utm-coordinates

A Quick Introduction to UTM Coordinates UTM coordinates are an option in nearly every outdoor recreation GPS receiver, and a common secondary grid on U.S. topographic maps. Most users leave their GPS on the default lat/lon setting and never explore UTM — but figuring it out is usually a meaningful upgrade for backcountry navigation. Two numbers — an easting and a northing, both in meters. At the local level, a UTM coordinate is a position measurement consisting of an east-west position and a north-south position, both measured in meters. It might look something like this: 10S 706832m E 4344683m N. It's good practice to include the unit of measure ('m' for meters) and the direction of the measurement ('N' for North, 'E' for East). It's also common to see only the numbers themselves: 10S 706832 4344683. By convention, the east-west measurement is always first. The east-west measurement is called the 'easting' and the north-south the 'northing.' The 10S at the beginning is the UTM zone. Important at a global level, but for now, just ignore the zone. These skills work in two directions: reading a coordinate from a feature on the map (you have a point, you want its coordinate) and plotting a coordinate onto the map (you have a coordinate, you want to find the point). Same tools, same techniques — the inputs and outputs swap. Both directions can be watched step by step in the interactive UTM tutorial, which animates the tool being placed and read on a real topographic map. What it Looks Like on a Map Common large-scale maps used for hiking — large-scale meaning more detail per square inch, like 1:24,000 — will have a 1000m UTM grid printed on them. They will be squares 1000 meters on a side. (Don't confuse them with Public Land Survey System Sections, which are 1 mile square, often printed in red and usually numbered in their center.) Where the UTM Grid lines meet the edge of the map, they will be numbered with their easting or northing value. The label could be either the full easting or northing in meters, or an abbreviated value omitting the rightmost 3 digits. In this example, the 707 is an abbreviation for 707000m E. Map edge with two adjacent UTM grid line labels shown in abbreviated form: '706' (short for 706000m E) and '707' (short for 707000m E) The labels on the edge of the map make up the first part of both the easting and northing values. The right-hand 3 digits of the easting and northing are the distance measured within the grid square. 1km UTM grid square with grid labels 706/707 (easting) and 4344/4345 (northing). A feature inside the square is annotated as 832m east and 683m north, combining with the labels to form the full coordinate 10S 706832m E 4344683m N What it Looks Like on a GPS Receiver A GPS receiver tells you the UTM coordinate of where you're standing. The most common reason to work in the plotting direction — turning a coordinate into a point on the paper map — is to take a GPS reading and figure out where on the map you actually are. Almost every GPS receiver designed for outdoor recreation use, and many phone GPS apps, can be set up to display UTM coordinates. See GPS Setup for Map Coordinates. It is common for a GPS receiver to display the zone and easting on one line and the northing on the line below. If you want your GPS's UTM coordinates to match up with the ones on your map, you will need to get the map datum set up correctly in your GPS. See Map Datums. Precision is a square on the ground A UTM coordinate (and MGRS and USNG, which are built on UTM) always describes a square on the ground, with the size of the square set by the precision of the coordinate. Useful intuition pumps: 1 meter square: about two doormats side by side. 10 meter square: about four parking places. 100 meter square: about two football fields side by side. 1,000 meter square: about a city block. If you plot a coordinate and the resulting square doesn't match the kind of feature it's describing — someone says "I'm at the trailhead" but the precision is 1 km — there's a precision mismatch worth catching out loud. Estimating UTM with 100m precision You don't always need a tool. The 1km UTM grid printed on a topo map is a built-in measuring tape — you just have to read it. If you can see a feature on the map and the surrounding 1km grid, you can estimate its position by eye. Do it in two passes — easting first, then northing. Easting (east-west position). Imagine dividing the west-to-east span of the 1km grid square into ten equal parts, each 100m wide. The part along the western edge is 000m; each part to the east is 100m more, so the middle of the square sits in the 400, 500, or 600m range and the part along the eastern edge is 900m. Northing (north-south position). Same trick going south to north: the southern edge is 000m, each part north adds 100m, the middle is 400–600m, the northern edge is 900m. Combine the two estimates with the printed grid labels for the full coordinate. If the easting label reads 706 and your easting estimate is 500m, the easting is 706500m E. The northing works the same way. The two estimates together place the feature in a 100m × 100m square — about the size of two football fields side by side. The reported value has 100m precision, but eyeballing is less accurate than that — picking the wrong 100m strip on either axis puts you 100m or more from the true position. To get accuracy that matches the precision, you need a tool. When writing or transmitting a 100m-precision coordinate, fill in the unmeasured digits with zeros — never round up. A point that is 146m east of the western grid line gets written as 706100m E, not 706200m E. The convention preserves a clear understanding of how precise the measurement actually is. Using a grid-style tool to measure UTM with 100m precision A grid-style tool is a transparent overlay carrying a printed grid that matches the map's 1km grid at the same scale. Lay the tool over the map so its grid lines align with the printed grid lines, with the relevant feature visible inside one square. Read the easting and northing off the marked subdivisions inside that square. 1:24,000 grid tool overlaid on a 1km UTM grid square on a topo map. The tool's printed 100m subdivisions help read the feature's position within the square; the truncated 100m-precision coordinate at the bottom is 10S 706800m E 4344600m N (true position 832m east, 683m north) Grid-style tools give you 100m precision and 100m accuracy — the printed lines tell you exactly which 100m square the feature is in, with no eyeball guesswork between strips. They're fast, conceptually clear, and mechanize the eyeball technique with lines drawn for you instead of imagined. MapTools sells a 1:24,000 pocket-sized grid tool in this family. Using a slot-style tool for more precision A slot-style tool trades the full grid overlay for a single open square (the "slot") with finely marked edges. The slot is shaped to fit a 1km grid square on the map. Slide the tool until the slot frames the relevant feature; the marked edges read out the easting and northing inside the slot. 1:24,000 slot tool laid over a 1km UTM grid square. Magnified callouts show the slot edge's fine marks aligned with the feature at 832m east, 683m north; the resulting 10m-precision coordinate is 10S 706830m E 4344680m N — the same feature as the grid-tool image, now resolved 10× finer The slot's edges are marked at 10m intervals, so you can write a coordinate with 10m precision and achieve close to 10m accuracy — meaningfully sharper than a grid tool, which tops out at 100m on both. The bottom edge of the slot sits on the southern grid line and slides east-west to frame the feature, keeping the tool parallel to the grid by physical contact rather than by eye. The vertical edge spans exactly 1km at the tool's scale, so its top should reach the northern grid line; if it falls short or overshoots, the tool's scale doesn't match the map's (see Map Scale). The slot tool is also the best of these tools for the plotting direction — turning a coordinate into a point on the map. From a coordinate like 10S 706830m E 4344680m N, the prefixes (706 easting, 4344 northing) name the 1km grid square. Lay the slot over that square with the bottom edge on the southern grid line. Mark the point at the easting and northing offsets — 830m east and 680m north — read directly off the slot's marked edges. Same marked edges, opposite operation. MapTools sells a 1:24,000 pocket-sized slot tool in this family. John's "personal favorite tool style" — "all the accuracy you need" and "easy to keep parallel to the grid lines." For a step-by-step walkthrough with photos, see the MapTools slot tools tutorial. When writing a 10m-precision coordinate, the same truncate-don't-round rule applies: a point at 146m east of the western grid line gets written as 706140m E, not 706150m E. The digits you write should reflect what you actually measured. At 1:24,000, 10m is the measurement floor — a 1m distance on the ground is too small to see on the map; for finer measurement, use a larger-scale map. Using a map ruler to measure UTM coordinates A map ruler is a longer, edge-marked ruler that doubles as both a UTM measuring tool (along the metric edges) and a Latitude and Longitude ruler (typically along the other edges). Lay the ruler perpendicular to the western grid line at the relevant feature, with the zero mark on the western grid line. Read the meters east of that line directly off the ruler. Repeat with the ruler perpendicular to the southern grid line for the northing. 1:24,000 map ruler measuring UTM coordinates in two passes: laid horizontally on the western grid line for the easting (left panel) and vertically on the southern grid line for the northing (right panel), with magnified callouts of each alignment. The resulting 10m-precision coordinate 10S 706830m E 4344680m N is the same feature as the grid-tool and slot-tool images — same precision as the slot tool, but requiring two separate placements Map rulers carry the same 10m markings as the slot tool, so they reach the same precision ceiling and same potential accuracy at 1:24,000. Two trade-offs versus the slot: Pro: the ruler doubles as a lat/lon plotting tool and a straight edge for bearings work, so it's a multi-purpose tool to carry. Con: keeping the ruler parallel to the grid line is the user's job. Slot tools enforce orientation; rulers don't. MapTools sells a 1:24,000 map ruler in this family. UTM From the Global Perspective The local easting and northing measured off a topo map are unique only inside one UTM zone. The Grid Zone Designation at the front of every coordinate (10S, 13T, 33N) is the zone label — it's what makes the full coordinate globally unique. UTM divides Earth's surface into 60 zones, each 6° of longitude wide, with latitude bands lettered C through X. For most backcountry use the Grid Zone Designation is just a label you copy off your map and include when sharing the coordinate. For the deeper picture — false easting, the flat-grid-on-curved-sliver geometry, convergence between Grid North and True North, and the polar regions — see UTM Zones. Other UTM-Based Coordinate Systems UTM is the underlying numerical grid. Two systems package it in alphanumeric form for different communities — MGRS for military and NATO use, USNG for civilian U.S. emergency response. Both inherit the UTM geometry wholesale; the difference is notation, not measurement. If you understand UTM, MGRS and USNG follow easily. If you don't, they look like magical pairs of numbers — and the abbreviated forms (6-digit, 8-digit) quietly invite digit-slip errors you have no way to catch. MGRS MGRS (Military Grid Reference System) is the U.S. military and NATO packaging, formalized in 1949 for artillery and inter-service coordination. The same physical point that UTM writes as 10S 706832m E 4344683m N is written in MGRS as: 10S GJ 06832 44683 The two-letter GJ is the 100,000-meter Square ID — a unique label for the 100km square inside zone 10S that contains the point. With the square identified, the easting and northing only need to express the position within that square, so they shrink from 6+7 digits to 5+5. MGRS abbreviates further by dropping trailing digits: 0683 4468 is 10m precision, 068 446 is 100m, down to 0 4 at 10km. The abbreviation made sense in the late-1940s era of Morse-code and scratchy-voice radio — keeping a coordinate short was a real operational constraint. Today it isn't, but the abbreviated forms remain in heavy use. They carry a real failure mode: slipping a digit one position left or right produces a well-formed coordinate at a totally different location, with no error indicator. UTM's fixed 6+7 digit count doesn't have this hazard. Use the full form. MGRS is the lingua franca for military, allied military, and many SAR teams. It also persists in civilian recreational use, especially among veterans. By default MGRS is referenced to WGS 84; older NAD 27 MGRS coordinates carry a 10-letter shift in the 100km square ID. See MGRS Coordinates for the full treatment, including datum handling. USNG USNG (the U.S. National Grid) is the civilian U.S. equivalent of MGRS. Same five-component structure, same map grid, same precision-by-digit-count convention — and the same digit-slip hazard in the abbreviated forms: 10S GJ 06832 44683 The two systems are nearly identical at WGS 84/NAD 83 precision. Where they diverge is in handling NAD 27 (USNG requires the datum to be specified explicitly; MGRS shifts a letter) and in geographic scope (USNG is defined only for the U.S. and its territories). USNG is what FEMA uses, what civilian SAR teams trained under FGDC standards use, and what some U.S. national parks have begun overprinting on their maps. See USNG Coordinates for the full treatment. Other Metric Grid-Based Coordinate Systems UTM is one of several metric-grid coordinate systems that work the same way in principle — pick a projection, lay a meter-based square grid over it, label the lines. Many countries publish their own — the British National Grid, the Irish Transverse Mercator, the Lambert Conformal Conic-based systems used in parts of continental Europe, and others. Two things to know: They are not UTM, even though they look similar at first glance — printed grid lines spaced in kilometers, easting and northing values measured in meters from a regional reference. The underlying projection is different, so a UTM-trained reader can't assume the numbers mean the same thing. At the plotting and reading level, they function similarly to UTM. The skills you learned here transfer: identify the grid square, measure the easting and northing within it, combine with the grid label. Outside the U.S., these systems are often more useful than UTM for in-country navigation, but UTM is still readable on most modern topo maps as a secondary grid. For interoperability work (international coordination, multi-agency response), UTM and lat/lon are the universal lingua franca everyone agrees on. Other national grids are best handled by converting to UTM or lat/lon at the boundary of the conversation. Choosing a coordinate system For guidance on when to use UTM vs. lat/lon vs. MGRS vs. USNG, see Selecting a Coordinate System. Further reading on maptools.com Interactive UTM Tutorial — the animated tutorial works both directions of this skill a step at a time on a real topo map: plotting a given coordinate, and reading a marked feature's coordinate. Use it when the question is where does the tool go rather than what do the numbers mean. UTM Quick Guide — tutorial walkthrough of reading and writing UTM Plotting with a UTM Grid Tool (video) — watch the tool go down on the map: laying a grid-style tool on the grid square and reading the easting and northing off it UTM on USGS Maps — how UTM appears on USGS 7.5' topographic maps Grid Zone Details — the UTM zone grid and what each piece means

### UTM Zones
https://maptools.com/learn/utm-zones

UTM divides the Earth's surface into a tiled grid of zones. Each zone is a flat, locally-rectangular projection of one slice of the curved Earth. The local easting and northing measured off a topo map are unique only inside one zone — the Grid Zone Designation at the front of a UTM coordinate (10S, 13T, 33N) is what makes the full coordinate globally unique. UTM Zones and Bands There are 60 UTM zones, each spanning 6° of longitude. World map showing all 60 UTM zones, numbered 1 to 60 starting at the international date line and proceeding east UTM zones are numbered 1 through 60, starting at the international date line, longitude 180°, and proceeding east. Zone 1 occupies 180°W to 174°W, centered on its central meridian at 177°W. Zone 60 wraps back around to the date line. Coverage extends from 80°S to 84°N — most of the inhabited Earth — with a handful of exceptions in northern Europe where zone boundaries are bent to keep small countries in a single zone. Within a zone, latitude is divided into 8°-tall horizontal bands labeled with letters from C (south) to X (north). The system skips letters I and O to avoid confusion with the numbers 1 and 0. Band X is the exception — it's 12° tall to extend coverage all the way to 84°N. A Grid Zone Designation is the zone number plus the band letter: 10S, 13T, 33N. The full Grid Zone Designation makes a UTM coordinate unique anywhere on Earth. Anatomy of a UTM Zone A single zone is a tall, narrow rectangle of about 20,000 km tall by 700 km wide at its widest. Inside the zone the UTM grid is a flat, square Cartesian system measured in meters. Diagram of a single UTM zone showing the central meridian, equator, and the false-easting / false-northing origins (the vertical axis is compressed about 15X — the real zone is much taller than it is wide) Animated illustration of a UTM zone, showing its position on the globe and how the flat grid is laid down across it Two reference values define the grid: Central meridian and false easting. The zone's central meridian is assigned an easting value of 500000 mE — exactly halfway across the conventional easting range. This arbitrary assignment is why eastings are sometimes called "false eastings": an easting of zero never occurs anywhere in the zone, because the convention pushes the origin off to the side. A 6°-wide zone never gets wider than about 674 km, so valid eastings fall in roughly the range: At the equator: 160000 mE to 834000 mE. At 84°N: 465000 mE to 515000 mE — the zone narrows substantially toward the poles. Equator and false northing. For locations in the northern hemisphere, the equator is assigned a northing of 0 mN and northings increase to the north. For southern hemisphere locations, the equator is assigned 10000000 mN (ten million meters north) and northings decrease to the south to avoid negative numbers. That second convention has a consequence: a northing alone is ambiguous between hemispheres. The latitude band letter resolves the ambiguity (bands C–M are south of the equator, N–X are north). What Happens at a Zone Boundary Zone boundaries are the seams where the flat-projection approximation has to break. Two practical consequences for the navigator: Coordinates across a boundary aren't directly comparable. A position 1 km east of the zone boundary has a different easting than a position 1 km west — the easting "resets" at the boundary because each zone has its own central meridian and false-easting origin. Subtracting the two eastings gives you a meaningless number. The map will tell you, but you have to look. USGS topo maps near zone boundaries show grid markings for both adjacent zones along the appropriate edge. Students who don't notice the second set of grid labels can produce coordinates that are off by enormous amounts. On a USGS topo map, the UTM grid appears in one of two forms — either printed black grid lines spaced every 1000 m and labeled along the edge: USGS topo map excerpt showing printed black UTM grid lines spaced every 1000 m, with edge labels like 248 and 249000mE …or, on older 1:24,000 quads, just blue tick marks along the neat line that the user is expected to connect with a straightedge: USGS topo map excerpt showing only blue UTM tick marks along the map edge, with no printed grid lines across the map face UTM grid lines are not exactly North-South or East-West anywhere but in the center of a zone. This is the convergence angle — the small twist of the UTM grid relative to True North and longitude lines, which grows toward the edges of a zone. See North References (True, Magnetic, Grid) and Declination for the full three-norths picture. For most recreational navigation in the middle of a zone, the convergence is small enough to ignore. Near a zone boundary, or at high latitudes where zones narrow significantly, it becomes meaningful. What about the polar regions? UTM doesn't cover the poles. Beyond 84°N and 80°S, the zones get too narrow to be useful and the projection breaks down. Polar coverage uses a separate system: the Universal Polar Stereographic (UPS) grid, which projects each polar cap onto a flat plane centered on the pole. For most users this is a footnote — UPS comes up only for polar expeditions, scientific work in Antarctica, and the occasional aviation chart. The U.S. National Grid avoids UPS entirely by limiting itself to U.S. territory. Further reading on maptools.com Grid Zone Details — the UTM zone grid and what each piece means

### Working with Bearings and Your GPS
https://maptools.com/learn/gps-using-bearings

How bearings and a GPS work together In modern land navigation, the GPS and the compass divide the labor. The GPS is excellent at telling you where you are and which direction a destination lies — it can compute a bearing to any waypoint instantly. The compass is excellent at holding that direction as you walk, especially under trees, in a canyon, or anywhere the GPS's own sense of direction gets shaky. The skill is reading a bearing off the GPS and then handing it to the compass to walk. This is the GPS-forward approach to land navigation, and it's faster and more reliable than either tool alone — but only if you understand the few distinctions below. Bearing-to-waypoint (GoTo) vs. compass bearing When you tell the GPS to navigate to a destination — a "GoTo" — it gives you a bearing to the waypoint: the direction, as an angle, from where you stand to that point. That number is a calculated bearing — the GPS computes it from your current location and the waypoint's location, and reports it relative to whichever north reference the GPS is set to. A compass bearing is the same kind of angle, but as your magnetic compass measures it. The two will only agree if the GPS is reporting the angle in a north reference your compass can match (more on that below). Conceptually they describe the same line; the question is always measured from which north? Course vs. bearing — they are not the same Two words the GPS uses that beginners blur together: Bearing is the direction from your current position to the waypoint. The GPS recalculates it — and the distance — every time your position updates, so it always points at the target from wherever you actually are. Course is the direction of the straight line between your starting point (A) and the destination (B). It's the fixed line you'd follow to go straight there. The recalculating bearing is one of the biggest reasons to navigate to a waypoint with a GPS instead of with a fixed compass bearing and distance. A compass bearing and distance describe only the straight line from A to B; step off that line to get around a cliff, a thicket, or a swamp and the number no longer points at your target. The GPS's bearing isn't tied to a line — it points from where you are to where you're going. You can detour around obstacles all day and still have a usable bearing and distance to the target. Most of the time that's exactly what you want: reach B by whatever path the terrain allows. Occasionally, though, you need to stay on the actual line between A and B rather than just arrive at B by a less direct path. That's when course matters. Two ways to hold it: Note the initial bearing and keep matching it. When you start, read the bearing to the waypoint and remember it. As you travel, keep the GPS's recalculated bearing equal to that initial number — as long as the two agree, you're still on the original A-to-B line. Drift to one side and the recalculated bearing will no longer match; that's your cue you've left the line. Navigate a route and watch the course deviation indicator. Set the leg as a route and the GPS shows a course deviation indicator (CDI) — how far off the line you are and which way to step back onto it. This is the more advanced technique. Turning a bearing and distance into a waypoint (projecting) Sometimes all you have is a bearing and a distance — "the cabin is 1.2 miles at 340°" from a description, a report, or a landmark you've sighted but can't reach. You don't need its coordinates to navigate there with the GPS. Most units have a project waypoint feature that builds the destination for you: Mark a waypoint at your current location. Run the project-waypoint feature on that mark, entering the bearing and distance. The GPS computes the coordinates of that point and saves it as a new waypoint. Now GoTo the projected waypoint and you get everything above — a recalculating bearing and distance from wherever you actually are, so you can detour around obstacles and still home in on the target. Projecting is how you turn a one-shot "bearing and distance" into a destination the GPS can actively navigate to. Enter the bearing in the same north reference your GPS is set to (see below), or the projected point lands off in the wrong direction. Heading is where you're pointed, not where you should go The GPS also shows a heading — the direction you are actually moving (computed from successive position fixes) or, on units with a magnetic sensor, the direction the unit is pointed. Heading answers "which way am I going?", bearing answers "which way should I go?" You steer by turning until your heading matches the bearing. Note that a movement-derived heading needs you to be moving to be meaningful — stand still and it goes nonsense. Set the right north reference, or every angle is wrong A bearing is only meaningful relative to a north. Your GPS can report directions referenced to True North, Magnetic North, or Grid North, and you choose which in the setup. This is the single most important setting for making the GPS and compass cooperate: if the GPS reports bearings in True North but your compass reads Magnetic North, every bearing you transfer will be off by the local declination — possibly many degrees. The fix is to decide on one north reference and set the GPS to it. See North References (True, Magnetic, Grid) and Declination for the three norths and GPS Setup for Map Coordinates for where the setting lives. Walking a bearing the GPS gives you The field procedure ties it together — and the key move is that you don't have to keep the GPS in your hand the whole way: On the GPS, start a GoTo to your waypoint and read the bearing. Set that bearing on your compass, then put the GPS away. Follow the compass: sight along it to pick a landmark on that line, walk to it, and repeat. The compass holds the line just fine on its own — no batteries, no waiting for fixes, reliable under tree cover and in canyons where the GPS struggles. Every so often, pull the GPS back out, read the current bearing (it will have shifted as you've closed in or drifted around obstacles), reset your compass to that new number, and put the GPS away again. That rhythm — get a bearing, walk it on the compass, re-check periodically — is the everyday GPS-forward technique. The GPS does the math and gives you a fresh, recalculated bearing whenever you ask; the compass does the steering between checks. You get the GPS's accuracy without draining its battery or staring at a screen while you walk. For the broader picture of GPS in the backcountry, see GPS for Land Navigation; for the compass side of bearings, see Compass Bearings.