Most lists of essential everyday carry outdoor gear include a map and a compass, but just having them is no magic talisman to keep you from getting lost or to get you where you want to go. You need to know how to use them.
This is the seventh and final installment in a series of short articles on basic map & compass skills. The first six articles/skills are –
- get a (good, durable) compass
- find a map with the right information for the kind of outing you’re going on
- be able to orient the map
- be able to find a given heading
- be able to walk in a straight line following a heading
- be able to find the heading to a landmark
The last skill is to be able to triangulate your position on a map using a compass. This means to be able to look at a map in relation to visible real-world landmarks and use the compass to find exactly where you are on the map.
If you have gone through the previous articles in this series, triangulation should be pretty easy.
- First, get someplace where you can see all around you (eg. a hilltop) and orient your map
- locate a landmark in the real world that you can also find on the map.
- use your compass to find the heading to that landmark. That is, point your DOT arrow at the landmark and then orient the compass to north.
- on your map, draw a straight line through the landmark at the heading you just read. You can use the compass baseplate as a straightedge. You know that you must be standing somewhere on that line.
- Repeat steps 2, 3, and 4 with another landmark. Once you have your second line drawn your two lines should intersect and you can be pretty sure that you are standing close to that intersection.
- Because there’s always the potential for error either in your heading reading skills or your line drawing skills, you can repeat these steps for a third landmark. Once you get your third line drawn, it should form a small triangle with the other two lines. You can be confident that you are standing in or close to that triangle. That’s why it’s called “triangulating your position.”
You can also tell how much error was in your readings – the smaller the triangle, the less error and the more confidence you can have about your position. If you managed to take three headings exactly right and mark them on the map exactly right, the three lines would cross at one point instead of a triangle!
Here is a pretty good video tutorial for some more reminder/explanation about these basic navigation skills.