Ok, here is another important skill you can use your G.I. Lensatic Compass for:

RESECTION

Finding the location of the user’s unkown position by sighting on two or three known features is called resection.

(1) Orient the map using the compass.

(2) Locate two or three known positions on the ground an mark them on the map.

(3) Measure the magnetic azimuth with the compass to a known position; convert to grid azimuth.

(4) Change the grid azimuth to a back azimuth and draw a line on the map from the known position back toward your unknown position.

(5) Repeat (3) and (4) above for a second known position.

(6) For a check on accuracy, repeat (3) and (4) for a third known position.

(7) The intersection of the lines is your location.  Using three lines, a triangle of error may be formed.  If the triangle is large, recheck your work.

 Sight a line to two or more known landmarks, convert your magnetic azimuths to grid azimuths and grid azimuths back to magnetic azimuths, calculate the back-azimuths of each point A, B and C, and draw intersecting lines back to discover your position on the map.

This lesson was adapted from Army Field Manual FM 21-26: Map Reading. You can get this manual and a shitload more from this site all bundled together into one secure download for only $6.99. Click the banner below for more information:

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Filed under: Tutorials by Patriot75