How do I take a bearing with a map and compass?

Taking a bearing is a mechanical procedure that works every time, in any visibility. Walking it accurately is the part that needs practice, because people drift without realising and stare at the needle instead of at the ground.

Safety

What you'll need

• A baseplate compass with a rotating housing
• A paper map of the area
• A waterproof map case

Step by step

1. Know where you are before anything else.A bearing from an unknown starting point is worthless. Fix your position against features you can see and identify on the map.
2. Lay the compass edge along your intended line.The long edge of the baseplate joining your position to your target, with the direction-of-travel arrow pointing towards the target rather than back at you.
3. Turn the housing to match the grid.Holding the baseplate still, rotate the dial until the orienting lines inside it run parallel with the map's north-south grid lines, and the orienting arrow points to the top of the map.
4. Read the bearing.The number at the index line. This is a grid bearing, taken from the map.
5. Adjust for magnetic variation.The difference between grid north and magnetic north. Modern British maps state it and it is currently small in much of the UK, but check the map's legend and apply what it says.
6. Lift the compass off the map and hold it flat.Level, in front of you, at about waist height, well away from your phone, keys, camera and any metal. Metal deflects the needle by amounts that matter.
7. Turn your body, not the dial.Rotate yourself until the red end of the needle sits inside the orienting arrow — 'red in the shed'. The direction-of-travel arrow now points the way you must walk.
8. Pick a feature on the line and walk to it.A rock, a post, a distinctive tuft. Walk to it, then take a new sighting. Watching the compass while walking is how people wander in slow curves.
9. Use a person in poor visibility.Send someone ahead, direct them left or right until they are exactly on the bearing, walk to them, repeat. It is how bearings are walked accurately in thick cloud.
10. Measure distance as well as direction.Count paces or use timing at a known speed. A bearing tells you the direction and nothing about when to stop, and stopping in the wrong place is as bad as walking the wrong way.
11. Aim off deliberately.To find a specific point on a linear feature such as a path or stream, aim deliberately to one side. When you meet the feature you know which way to turn instead of guessing.
12. Practise in good weather.On familiar ground where a mistake costs nothing. The procedure has to be automatic before you need it in cloud and wind.

Tips

• Turn your body, not the dial, once the bearing is set.
• Walk to a visible feature on the line, then re-sight. Do not walk staring at the needle.
• Keep the compass away from your phone. It deflects the needle enough to matter.

Common mistakes

• Putting the compass edge the wrong way round — The direction-of-travel arrow must point from you towards the target. Reversed, you get a bearing exactly 180 degrees out and walk away from where you intended.
• Taking a bearing with the compass near metal — Phones, keys, camera bodies, ice axes and car bonnets pull the needle off by degrees or tens of degrees. Over a kilometre a few degrees is a substantial error.

If it doesn't work

Questions people ask