How to use a compass
A compass is a simple device, it is nothing more than a magnetized needle that responds to the earth's magnetic field. One end of the needle is marked "N" for north or colored (often red) to show that it points north. The needle points to magnetic north, not to true north. 360 degrees A basic magnetic compass consists of a transparent rectangular base plate, including a direction of travel line and a needle. The needle is protected by a circular rotating housing filled with a fluid that reduces the vibrations of the needle. Below the needle, you have an orienting arrow and a set of parallel meridian lines. A dial around the circumference of the housing is divided just as cartographers divide the earth, into 360 degrees. You also have the letters N, S, E and W for North, South, East and West: - North is 0 (360) degrees - East is 90 degrees - South is 180 degrees - West is 270 degrees Declination Topo maps have information about the "magnetic declination" or the angle difference between true north and magnetic north. This angular difference must be considered whenever you use your compass, since the compass needle points to magnetic north, and you want to know which way is "true north". A good way to compensate for the declination is to use a compass model with an adjustable declination arrow and follow the instructions supplied from the manufacturer to set the adjustable arrow for any declination. Check your map to get the declination value to use. Compass readings are also affected by the presence of iron and steel objects. Be sure to look out for, and stay away from, knives, belt buckles and so forth when using a compass in the field. Always bring a pocket compass as a backup unit. It's good if your primary unit would be lost or broken. Reach your destination To decide the direction from one point to another you have to learn to take a bearing. To avoid getting off course, make sure to look at the compass quite frequently. Stay alert and observe all unusual landmarks. Check your map. If you can't point out your actual position on the map, locate yourself by cross-bearing. to: "How to read a map and a compass" Back to: Wilderness backpacking homepage
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