Using a Compass



Magnetic Declination Scale 2019

Declination Scale from Utah Co. in 2019

compass always works, even if your GPS is out of power. It works by following the magnetic fields created by the earth and pointing to the magnetic poles. To maintain the correct magnetic polarity of your compass, keep it away from magnetic fields produced by mobile phones, radios, magnets, and other metal objects. Know that magnetic north is different than true north. This difference is known as magnetic declination. Declination is a positive angle when east of true north and a negative angle when west of true north. Declination changes over time and depends on your location on the earth. If you are going on a trip dependent on a magnetic compass, check the declination adjustment for the area you will be navigating before you go. Also use an updated map that may have the current declination for the area. Some compasses have declination lines that show you how much to adjust your readings if you know the declination. Other compasses have an adjustment screw that can correct the compass for declination. The important thing is to know how your compass works and that it points to magnetic north, not true north. Read your manufacture's instructions and ask your outdoor retailer to know how to use your specific compass.

Other than just knowing north, south, east, and west, compasses work best with a map of the area you are navigating. Place the compass on your map and rotate the map until map north and compass magnetic north line up together. Then compensate for magnetic declination. With the map correctly oriented, look at your surroundings and match landmarks in your area with landmarks on your map to determine your location. When you know where you are, figure out where you want to go on the map, and determine a safe route between the two. Turn your body until you are facing the correct direction at the start of the route you have chosen. Now follow the route and maintain the correct orientation of your map (always have map north pointing toward true north) as you travel. Each time you reach a landmark, check the map and compass to be sure you are on the correct path.

There are many different kinds of compasses. What ever compass you have and use, it is important to know how it works and to practice with it often. These three are the most common.

Survival Button Compass

Survival Button Compass

Simple survival compasses just show you the direction of magnetic north and may have a few other degree markings. These work best if you already know which general direction you are going and just need to orient yourself or your map to find your direction of travel. These are often found in small survival kits. If the compass is part of a survival knife or survival tool, make sure that other pieces of metal are not interfering with the reading of the magnetic compass.

Orienteering Compass and Map

Orienteering or Base Plate Compass

Orienteering or base plate compasses are designed to be used with a map and are mounted on a clear plastic plate that allows you to see the map beneath the compass. To use an orienteering compass, mark where you are and where you want to go on the map. Place the compass on the map, orienting the side of the compass to connect the beginning and ending points. Now, without moving the compass body, turn the arrow on the compass dial to lineup with the meridian, or north/south lines, on the map. Be sure to have the compass dial north arrow point toward map north. Finally, lift the compass from the map and turn the compass and your body until the north end of the compass needle fits inside the compass dial north arrow. Look across the arrow on the compass body for the direction you will be traveling and sight a landmark in that line. Begin walking. Read your manufacture's instructions and ask your outdoor retailer to know how to use your specific compass.

Lensatic Compass

Lensatic Compass

Lensatic compasses kind of look like a clam shell and have a sighting wire and sighting lens (hence the name "lensatic") to orient to distant objects. Like the other compasses, use the magnetic north shown on the compass to correctly orient the map to your surroundings. Once your compass is parallel to the route on your correctly oriented map, turn the bezel ring so that the marker is over the compass arrow pointing north. Look at the bearing or direction of travel indicated on the compass. Now, move the lens arm of the compass to a 45° angle and the top of the compass with the wire sight to a 90° angle. Lift the compass to eye level and look through the lens at the bearing, rotating the compass and your body to reacquire the correct bearing from the map. Finally, holding that bearing, simultaneously look through the sight wire to establish a landmark in the distance to walk toward. Each time to reach your landmark, reorient the map and take another bearing until you reach your destination. Read your manufacture's instructions and ask your outdoor retailer to know how to use your specific compass.

Navigation Without a Magnetic Compass

There may be times that you may find yourself needing to orient yourself and navigate when you don't have a standard compass. Knowing how to navigate can help you survive in a difficult situation.

Sun Compass diagram showing shadows cast by a stick in relation to the sun.

Sun Compass

Sun Compass: As long as you have sunlight, you can find north and south, and then determine east and west. Find a straight stick about 10 to twelve inches long. Push the stick into the ground so it is standing straight up and casts a shadow on the ground. Mark the tip of the shadow (W). Wait 15 to 30 minutes and the shadow will have moved in relation to the sun. Mark the tip of the shadow again in it's new position (E). Draw a line connecting point W(est) and point E(ast). Draw a perpendicular line (90°) between W and E. This line, opposite from the stick, points north. The other direction of the perpendicular line is south. This gives you basic directions of travel. If you are relying on this method for navigation, repeat the process every couple of hours while you have daylight.

Watch Compass

Watch as a Compass

Watch Compass: If you have an analog watch (a watch face rather than digital numbers) you can also use it as a makeshift compass. These directions are for the northern hemisphere. Orient your watch so the hour hand points toward the sun. Imagine a line that is midway between the hour hand as it points toward the sun and the 12:00 position of the watch face. This line points to the south and the opposite direction is north. Facing south, left is east and right is west. If you only have a digital watch, draw a watch face with the current time on a piece of paper and orient it toward the sun the same way.

Polaris North Star

Polaris North Star

Polaris North Star: For survival navigation at night, Polaris, or the North Star, always points north in the sky. Once you know which direction is north, you can figure south, east, and west. To find Polaris, first find the Big Dipper. The two outside stars in the "scoop" of the Big Dipper point to the tip of the "handle" of the Little Dipper. This is Polaris.