This document provides instructions on how to use a compass for map orientation, taking bearings, and performing resections. It explains the differences between grid north and magnetic north, and that the magnetic variation in New Zealand is approximately 22 degrees. When transferring bearings between a compass and map, 22 degrees must be added or subtracted depending on the direction. Resections involve taking bearings on at least two visible features to triangulate your position on a map.

1. How to use a compass
Features of a compass Magnetic Variation
- Grid north is the direction of the vertical
lines on a topographical map and is used
when measuring bearings on a map.
- Magnetic north is the direction that the
magnetic needle points to on a compass.
- In New Zealand the magnetic variation is
around 22 degree
Magnetic variation is important for when you are doing map and compass work. When using a
magnetic bearing and putting it ONTO a map you need to ADD the magnetic variation (22 degrees).
When using a grid bearing and taking your compass OFF the map you need to TAKE OFF or
SUBTRACT the magnetic variation (22 degrees)

2. Orientating your map using compass
- Put your compass onto the map with the dial turned so the orientation lines match up with
the grid lines on your map.
- With your map and compass flat rotate both to line the magnetic needle up with 22 degrees
line.
(- alternatively you can set your compass to 22 degrees and “put red in the shed”)
- Your map should be orientated.
Taking a bearing using features in the field
This is useful if you can temporarily see a feature in the field you want to get to so then you can
follow the direction of your compass to get to it.
- Point the directional arrow of your compass at your feature
- Turn the dial until the magnetic needle lines up with north on the dial (or “put red in the
shed”)
Taking a bearing from the map
This is useful if you cannot see a feature that you want to get to (because of poor visibility i.e. fog or
mist) but you know where you are on the map.
Using your map and compass:
- Find where you are on map (point A)
- Find where you want to go on map (point B)
- Get your compass and line up the side of your compass base plate with the directional arrow
pointing where you want to go.(From point A to point B)
- Move the dial to line the orientation lines up with the grid lines on map so all pointing north.
- Take the compass off the map and look at bearing.
- Take off 22 degrees to that bearing (magnetic variation), moving the dial. E.g. if you had 42
degrees move the dial so it points at 20degrees.
- “Put red in the shed”.
- The direction the directional arrow is pointing to on your compass is where you should
follow

3. Resections (triangulations)
This skill is really useful to learn while you are navigating and has the purpose of locating where you
are on the map if you are lost.
It is useful when you can see around you 2 to 3 or more features that you can locate on your map.
The more you have the better, to give you an accurate pinpoint.
- Choose a feature you can clearly see both in the field and on map.
- Point the directional arrow at your feature in the field
- Turn the dial until the magnetic needle lines up with north on the dial or “put red in the
shed”
- Add 22 degrees because you are adding your compass to the map (magnetic variation).
- Put your compass on to the map with the edge of the base plate touching the known feature
on the map with the direction of travel arrow pointing towards the feature.
- Turn the whole compass around until the orientation lines of the compass line up with the
grid lines on the map. Pointing north to south
- Draw a line on the map along the edge of the compass making sure it intersects the known
feature.
- Repeat with another known feature preferably in another direction.
- You are located where the lines intersect.