June 2021 - Intermediate Navigation Skills - Map Skills
by Nigel Williams
Key to this stage is developing contour interpretation, getting to grips with the third dimension. As the terrain and map scale offers less in the way of tangible features they become more relevant. Even when walking on a path, look for changes in the contour spacing and the angle that the path crosses the contours. It is not just that the contours being closer means that the path will get steeper, but noting exactly where the changes happen enables us to pinpoint our location.
Using the altimeter on the free OS Locate App, one can quickly confirm the location. Off the path one can practice contouring, perhaps identifying a stream junction a few hundred metres off to the side of a path. Note its altitude from the map. Leave the path at that altitude and try to contour to the junction by keeping the altimeter reading within around 5m of the target height. See how close you are to the junction when you get there.
The altimeter is generally accurate to around 5m - 10m so don't expect it to be perfect, but the exercise gives you a feeling of contouring and venturing off the path. Now go back to the path contouring without the altimeter. Lastly think about slope aspect (described in the beginners blog) and actively observe the changes along the route.
Just doing these practice exercises will considerably extend your navigation skills and confidence.
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