I hinted at resection in lesson one on the website. If you were
lost or unsure of your location but could identify two or prefer
-
ably three features in the terrain then you could use resection
to find your location. The more equally spaced the features are
around you the more accurate the result will be.
Take a magnetic bearing from one of the features and make
an allowance for magnetic variation. The compass is placed
on the map and you align the orienting lines on the compass
with the grid lines on the map. Slide the compass over to the
feature you recognise. When the feature rests against one edge
of the compass you can draw a line on the map (preferably in
pencil). Your position will lie somewhere along an extension of
this line. To find out exactly where on the line you will need to
repeat this process using other known features. Where the lines
intersect they will form a ‘triangle of error’ and your location
will be somewhere inside this triangle.