game Land Navigation

[Blackheart_Six 273]

NAVIGATION: Find a 4, 6, and 8 digit grid coordinate.

 

TASK: LOCATING A POINT USING THE U.S. ARMY MILITARY GRID REFERENCE SYSTEM

CONDITION: GIVEN ONE MAP, COMPASS, PROTRACTOR, AND PENCIL

STANDARD: Determine a 4, 6, and 8 digit grid coordinate without error.

 

There is only one rule to remember when reading or reporting grid coordinates⎯always read to the RIGHT and then UP. The first half of the reported set of coordinate digits represents the left-to-right (easting) grid label, and the second half represents the label as read from the bottom to top (northing). The grid coordinates may represent the location to the nearest 10-, 100-, or 1,000-meter increment.

4 digits = 1000 meters

6 digits = 100 meters

8 digits = 10 meters

 

Example Image of 4 digit Grid coordinates.

 

To find a 4 digit grid coordinate of the area called "Green Valley" -

1. Read right first - 08
2. Read up second - 03
3. Where the 2 lines intersect, the grid coordinate is 0803. The grid square to be referenced is RIGHT and UP from there.

 

To find the 6 digit grid coordinate for the tee intersection of the primary and secondary road, west of the "G" in green -

1. Read the right and up again (08_03_).
2. Place your protractors 1:25,000 meter scale on the 0803 grid line. Line up the 0/0 of the scale to 0803 grid line. See image. 

 

      3. Slide the protractor right until the vertical scale is over the object.

 

       4. Read RIGHT and UP to get the 6 digit coordinate of the tee intersection. Round to the closest whole number. In our example, it is 5 and 5. The 6 digit grid coordinate is 085035.

       5. This will get you within 100 meters of the target or objective.

 

To find a 8 digit grid cordinate

1. Follow steps 1 through 3 above.
2. Read right and up, and get the exact number of the scale. The 8 digital grid coordinate is 08530352.
3. This will get you within 10 meters of the target or objective.

 

[Blackheart_Six 273]

NAVIGATION: Intersection and Resection

 

TASK: Locate an Unknown Point on a Map and on the Ground by Intersection

CONDITIONS: Given a standard 1:50,000 scale military map of the area, the location of two known points, a compass, a straight edge, a coordinate scale and protractor (GTA 5-2-12), a pencil, and an object or terrain feature.
STANDARDS: Determine the 100,000-meter-square identification letters and six-digit grid coordinates of the object or terrain feature to within 100 meters

 

Intersection is the location of an unknown point by successively occupying at least two (preferably three) known positions on the ground and then map sighting on the unknown location. It is used to locate distant or inaccessible points or objects such as enemy targets and danger areas.

 

1. Move to a known point "A" (Hilltop).
2. Shoot azimuth to location you are trying to find.
3. Place your protractor on known point "A".
4. In the center of protractor, click on map to start the line. Draw out to the edge of the protractor to the degrees measured.
5. Move to a second known point "B".
6. Repeat steps 2 through 5.
7. Where the two lines intersect is the unknown position, and able to get a grid coordinate of location or target.

NOTE: Occupy a 3rd point for greater accuracy.

 

TASK: Locate an Unknown Point on a Map and on the Ground by Resection.
CONDITIONS: Given an unknown location, a standard 1:50,000 scale military map of the area, a compass, a straightedge, a coordinate scale and a protractor (GTA 5-2-12), a pencil, and two terrain features visible from your location and identifiable on the map.
STANDARDS: Determine the 100,000-meter square identification letters and six-digit coordinate of your location to within 100 meters of the actual grid coordinates.

 

Resection is the method of locating one’s position on a map by determining the grid azimuth to at least two well-defined locations that can be pinpointed on the map. For greater accuracy, the desired method of resection would be to use three or more well-defined locations.

 

Resection:

1. Shoot azimuth to a known point "A" on the map.
2. Calculate the back azimuth. IE 200 degrees - 180 = 20 degrees. Rule: Greater than 180, subtract 180. Less then 180, add 180.
3. Place your protractor, centered over known point "A".
4. Use drawing tool, and start at the center of the protractor. Draw out to the edge at the calculated degrees.
5. Repeat steps 1 through 4.
6. Where the lines intersect is your location on the map. If you do 3 points, the area of the formed triangle, is your location.

NOTE: Locate a 3rd known point for greater accuracy.

 

Actual Position

 

Map Resection Position