Military maps are used during land navigation exercises and daily military operations. The purpose of a military map is to allow a service member to find his way from one point to another using grid coordinates, terrain features and topographic symbols. Military maps are measured in meters. Although the military has largely converted to the use of digital maps with full search functions, military maps serve troops without access to this technology. Military maps are generally classified as "For Official Use Only," commonly referred to as FOUO, or "Secret." They are not released to the general public.
Determine whether you have the correct map. The top of each military map contains a map name that defines the territory it covers. For example, if you need to navigate Wheeler Army Airfield, make sure the top of the map is labeled as such. Orient the map so that North is at the top to make map reading easier.
Read the legend of the map. Military map legends are always in the lower-left margin. The legend contains information on each topographic symbol used on the map. Railroads, two-lane highways, vegetation and bodies of water are some of the things identified on military map legends.
Locate the point on the map for which you need a grid coordinate. Use terrain association if you are physically located somewhere on the map and do not know your precise location. Consult the legend on the map to determine your location. For example, if there is a cliff to your right, a set of railroad tracks to your left and a river flowing in front of you, orient the map to match the direction you are facing and find those items on the map.
Use a military protractor to determine the grid coordinates. Make sure the protractor is face up, then place the triangle cutout of the protractor over the grid square in which you are located. A military protractor is a sheet of clear plastic; it is face-up when the numbers and letters stamped on it are readable and not backward. Place the bottom right corner of the triangle cutout in the bottom right corner of the grid square and make sure the edges are flush. Locate your point, and count the number of tick marks on the bottom and the right side of the triangle cutout that correspond with your point.
Create your grid coordinate by applying the appropriate numbers. Generally, the military uses 8-digit grid coordinates. However, you can determine 4-, 6- and 8-digit grid coordinates. When reading a military map, use the number along the left border of each grid square as your starting point; then read the number along the bottom border. The general rule of military map reading is "right and up," which means you read a military map to the right of each left border and upward from each bottom border.
Create your 4-digit grid coordinate by reading the number that applies to the left line of your grid square and the number that applies to the line on the bottom of your grid square. If the left line number is 17 and the bottom line number is 48, your 4-digit grid coordinate is 1748. You do not need a protractor to determine a 4-digit grid coordinate.
Create your 6-digit grid coordinate by reading the numbers that apply to the left and bottom lines of your grid square and the single-digit number on the bottom and right side of the large triangle cutout on your military protractor. For example, if your left line number is 17, the bottom line number is 48, and the triangle cutout tick marks read 3 on the bottom and 6 on the right, your grid coordinate is 173 486.
Create your 8-digit grid coordinate by reading the numbers that apply to the left and bottom lines of your grid square and the double-digit number on the bottom and right side of the small triangle cutout on your military protractor. For example, if your left line number is 17, the bottom line number is 48, and the triangle cutout tick marks read 12 on the bottom and 14 on the right, your 8-digit grid coordinate is 1712 4814.
Items you will need
Army Field Manual 3-25.26
A 4-digit grid coordinate will get you within 1,000 meters of your selected point. A 6-digit grid coordinate will place you within 100 meters of your selected point. An 8-digit grid coordinate will locate your point within 10 meters.
Check the map legend on each different military map you use. Topographic symbols may vary slightly between maps, and not all maps contain all symbols. Make sure your map and your protractor are oriented correctly before attempting to obtain a grid coordinate.
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