A magnetic compass is designed to show you which way is north. Knowing that, you can figure out the other cardinal directions: east, west, and south. If you always know where north is, you can also walk in one direction and backtrack later to the point where you started. Why is that useful?
Let’s say you step off a well-marked trail and walk into the forest to pee. Afterwards, you can use a compass to backtrack to the trail if you’ve forgotten which direction it is. This is easy if you know how to find north.
While this may sound like a trivial example, hikers have died because they couldn’t find their way back to the trail after stepping off it to pee. I know of one hiker who died this way. It’s especially tragic because they were carrying a compass but didn’t know how to use it.
I’d encourage you to take the next 5 minutes to learn this skill if you don’t already know how to do it.
This example doesn’t require a map, topographic map reading skills, or understanding declination. It just explains how to use a compass:
- to find north
- to find the other cardinal directions: south, east, and west
- how to walk in a straight line, relative to north
- how to backtrack along the straight line
These are the basic building blocks of using a compass. They’re easy to learn and the foundation of all land navigation.
The Magnetic Needle
A hiking compass, like the one below, has a magnetic needle which spins around inside a dial. Most of the time, the north end of the needle is colored red or sometimes yellow.
To Find North
To find north, pick up the compass and hold it level with the dial is on top. The red end of the magnetic needle will point north. Ignore all the other markings on the compass except the direction that the red half of the needle points to.
Now: turn around slowly and continue to hold the compass level. As you turn around, the needle will spin inside the dial. But the red end will always point in the same direction, north, no matter which way you are facing.
Put Red in the Shed
There’s an outline of an arrow inside the dial, called “the shed”. Turn the dial with the numbers on the outside , so that the red end of the magnetic needle fits inside the outline. This is called putting “red in the shed.”
This doesn’t change the direction that the red end of the magnetic needle points to when you hold the compass level, it just makes it easier to locate North, South, East, and West on the dial, and the numbers, which are degrees that correspond with them. For example,
- North is 0 degrees
- South is at 180 degrees
- East is at 90 degrees
- West is at 270 degrees
The hash marks in between the cardinal directions are also measured in degrees.
Direction of Travel Arrow
Let says you’ve been hiking along a trail and you need to pee. Turn the compass perpendicular to the trail in the direction you want to walk to take a pee. Holding the compass level in your hand with the dial on top, sight down the direction of travel arrow along the direction you plan to go. Twist the dial of the compass, so red is in the shed, while keeping the direction of travel arrow pointed toward you plan to walk. Read off the number at the bottom of the direction of travel arrow, which is 282 degrees the example above.
Start to walk in the direction of the direction of travel arrow, holdings your compass level and in front of you, keeping red in the shed as you walk. This is called following a bearing. Walk out a ways and do your business.
Subtract 180 degrees from the bearing you followed previously. Turn the dial, so that the number 102 (282-180) is at the base of the direction of travel arrow. Holding your compass level in front of you, turn so red is in the shed, and start walking in the direction that the travel arrow is pointing. This will return you to the point where you left the trail (or very close: people drift left or right 3 degrees when they follow a compass bearing, although this rarely matters over short distances.)
If the first bearing was less than 180 degrees, you’d subtract 180 from it, and add the resulting negative number to 360 to get the back bearing. For example, if your first bearing was 60 degrees, you’d subtract 180 from it, and then add 360, which would give you your back bearing to the trail. (60-180)+360=240. Hint: if you don’t like math, trace your finger down to the base of the direction of travel arrow to the other side of the dial – see Figure 4. If the bearing to your pee point is 282, the back bearing back to the trail is 102.
Basic Compass Use
These techniques are the basic building blocks for compass use. They’re so basic, you don’t have to have a map, know the difference between magnetic north or true north, or about magnetic declination to use them. All that comes later and builds on the techniques described here. Being able to find a fixed point of reference, in this case magnetic north, and to follow bearings relative to it is an incredibly powerful tool for hikers: a skill that is easy to learn and can save your skin.