How to Use a Compass



A compass is crucial in finding direction in the middle of a forest, sea or even in a city. A simple tool based on the earth's magnetic field that has been around for centuries, the compass will, if used correctly, find the right direction.


Steps   [edit]

To "take a bearing"; i.e. use a compass to find your direction of travel

  1. Place the compass flat on your palm, and your palm in front of your chest.
  2. Point the direction of travel arrow in the direction you wish to take a bearing.
  3. Rotate the compass housing until the orienting arrow (on the compass housing) lines up with the north end of the magnetic compass needle.
  4. Read off the bearing marked on the edge of the compass housing that aligns with the direction of travel arrow.
  5. You can now plot the direction you have just taken a bearing of on the map. Take off local magnetic variation (i.e. take off the difference between magnetic and true north) by rotating the compass housing. Place the compass on the map, holding both horizontally, and rotate the whole compass to line up the orienting arrow and lines with the map's North lines. Move the compass so that its edge passes through your current position and maintains its alignment with the map's North line.
  6. Draw a line through your current position and along the compass' edge. Your path from your current position will be along the line along the edge of the compass if you maintain this bearing.

To "follow a bearing"; i.e. use a compass to walk in the right direction

  1. Hold map horizontally and place compass on the map.
  2. Adjust compass so its edge passes through your current position and the position you intend to walk to.
  3. Rotate the compass housing until the orienting arrow and lines are parallel with the North lines of the map.
  4. Put the map away. Read off the bearing reading from the compass housing and add local value of magnetic variation.
  5. Hold compass horizontally with the direction of travel arrow pointing away from you. Turn to face in a direction where the North needle lines up with the orienting arrow on the compass housing.
  6. Look down the direction of travel arrow and focus on an object in the middle distance that it points to e.g. tree, telegraph pole etc. Walking towards this object will take you towards your intended position.
  7. If visibility is limited and you cannot see any distant objects use another member of your walking party. Ask them to walk away from you in the direction indicated by the direction of travel arrow as you stay in the same spot. Call out to correct their direction as they walk. When they approach the edge of visibility ask them to wait until you catch up.
  8. When you reach the object you selected or the person you are directing make another bearing by repeating these steps.

To triangulate - finding your current position using bearings on visible landmarks

  1. Choose 3 prominent landmarks that you can see and also find on your map. These should be as widely spread around your field of view as possible.
  2. Aim the compass' direction of travel arrow at the landmark and take a bearing.
  3. Adjust for magnetic variation.
  4. Place the compass on the map and orientate it so the edge of the compass passes through the landmark on the map and the North lines on the compass housing line up with the map's north lines.
  5. Draw a line along the edge of the compass through the landmark and your approximate position.
  6. Repeat for each landmark to produce a small triangle where the lines intersect. Your position is inside this triangle, the size of which depends on the accuracy of your bearings. More accurate bearings reduce the size of the triangle and, with lots of practice, you may get the lines to intersect at one point.

Tips   [edit]

  • The compass' tips are usually marked with either red or black tips. One of these will be north, and the other south, and it is a good idea to test the compass out on which tip is north. A way of testing this is finding out the general north or south direction of where you are, then using the compass to align to one of these directions to see which point is which.
  • Hold the compass up to your eye and look down the direction of travel arrow to ensure it's pointed precisely in the direction you which to take a bearing of.
  • You can also hold the compass square to your body by holding the sides of the baseplate between both extended index fingers and your elbows against your sides. Stand facing your objective, look straight ahead, and square yourself with the object on which you are taking your bearing. The imaginary line extending out from your body will travel through your compass, along the direction of travel arrow. You can even rest your thumbs, against which the back of the compass is resting, against your stomach to steady your hold--just be sure you aren't wearing a big steel belt buckle or some other magnetic material close to the compass when doing this, or it will deflect the needle.
  • Magnetic variation is required because the North lines on your map run to the North Pole and magnetic North moves around and doesn't coincide with the North Pole - it's currently around North Canada. Magnetic deviation is printed on the edge of your map. The angle changes depending on where you are in the world. Many compasses have a means by which you can adjust for magnetic declination, either on the fly using a declination scale inscribed on the baseplate of the compass, or semipermanently by turning the capsule the required direction and degrees inside the compass housing (bezel). Read your compass's instruction manual for instructions particular to your compass.
  • It's often easier to use features in your immediate vicinity to locate your precise position. Triangulation is more useful if you're really lost or you are in a barren, featureless area.