Find Your Location Using Resection
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.
- When using the map and compass method--
- Orient the map using the compass.
- Identify two or three known distant locations on the ground and mark them on the map.
- Measure the magnetic azimuth to one of the known positions from your location using a compass.
- Convert the magnetic azimuth to a grid azimuth.
- Convert the grid azimuth to a back azimuth. Using a protractor, draw a line for the back azimuth on the map from the known position back toward your unknown position.
- Repeat 3, 4, and 5 for a second position and a third position, if desired.
- The intersection of the lines is your location. Determine the grid coordinates to the desired accuracy.
- When using the straightedge method--
- Orient the map on a flat surface by the terrain association method.
- Locate at least two known distant locations or prominent features on the ground and mark them on the map.
- Lay a straightedge on the map using a known position as a pivot point. Rotate the straightedge until the known position on the map is aligned with the known position on the ground.
- Draw a line along the straightedge away from the known position on the ground toward your position.
- Repeat 3 and 4 using a second known position.
- The intersection of the lines on the map is your location. Determine the grid coordinates to the desired accuracy.