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Eastern Washington Orienteering Club

Using A Compass With A Map


Turn the compass bezel in line with north on the map…

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The raised, numbered ring on the compass is called the bezel, and it rotates independently of the baseplate. Leave the baseplate lined up with your route and turn the bezel until "N" on the ring points toward north on the map. The center of the ring is conveniently transparent so you can see the map through it. Adjust the bezel until the painted lines and arrow in it are parallel with the north-south lines on map. This step effectively records an angle on your compass — the angle between north (0°) and your intended direction of travel (about 236° in this example).

Bonus Details

Here's another step where you have to be careful about the "180 error." It's not enough to have the compass lines parallel to the north-south map lines. Make certain that the arrow in the bezel is facing the same way as the map arrows as shown in the photo above. If you get it backward you'll end up heading the exact wrong way in the next step.
Since north is directly toward the top of an orienteering map, the lines on the compass bezel should end up parallel to the edges of your map. (Again — just make sure the arrow is pointed toward the top of the page.)
Usually, one or more of the compass lines will end up pretty close to a north line on the map and it's pretty easy to line them up by eye. If you want to adjust the distance between lines you can slide the baseplate of the compass a little bit forward or backward along the direction of travel. As long as you don't rotate the baseplate, you'll still be measuring the angle accurately.
The direction you want to travel in this example turns out to be about 236°. In the sport of orienteering you usually won't care about the number. In fact, on more specialized thumb compasses, the numbers aren't even shown. (See Thumb Compass Step 1.) If for some reason you do end up making a note about your heading, remember that most handheld compasses read in 2° increments.