Finding your position

Resection: using known summits or features to fix your position on the map.

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Spot two or three landmarks you can identify both in the field and on your map — summits work well. Take a compass bearing to each one, enter them below, and the tool plots the back bearing from each landmark on the map. Where the lines cross is your position. Three landmarks are more reliable than two: if your bearings are slightly off, you'll get a small triangle (a “cocked hat”) instead of a single point, and your real position is somewhere inside it.

↑ Grid north Summit A Summit B Summit C

Bearings taken to each summit

The technique

  1. Identify each landmark both on the ground and on your map.
  2. Take a compass bearing from you to each landmark.
  3. Plot the reciprocal (back) bearing as a line starting from each landmark on the map.
  4. Your position is where the lines meet — ideally choose landmarks spread around you, not clustered in one direction.