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Calculating your position using crossbearings.
To find your position using crossbearings you will need a sighting compass and two visible landmarks whose position you already know on the map. For example, you may be on a large mountain slope with two visible summits but not sure of your exact location on the slope.
1. Sighting the first Landmark
Sight your compass towards the first landmark. Turn the compass housing to align the north pointing needle with the red arrow on the base of the compass housing.
2. Mark the map for the first landmark
Place the compass on the map with the edge of the baseplate coinciding with the location of the first landmark. Turn the whole compass around this point until the straight lines marked in the bottom of the compass capsule are parallel with the north/south meridians on the map.
Draw a line on the map along the edge of the base plate from the first landmark. Your position will be somewhere along this line.
3. Using the second landmark
Repeat the procedure using the second landmark. Your current position is where the two lines cross.
Hint : You can use additional known landmarks to increase the accuracy of the crossbearing technique. The accuracy of the technique is also affected by the angle between your position and the two landmarks. If possible choose landmarks which are close to 90 degrees apart.
Written by TrackLogs Digital Mapping. Copyright TrackLogs Digital Mapping 2002-2017. All rights reserved. Please send any comments, questions or feedback to email@example.com
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