- Topographic maps are drawn to true north (North Pole). However, a compass points to magnetic north, which is in the Hudson Bay area. The difference between true north and magnetic north is called “declination.”
- When true north and magnetic north are aligned (0° declination), the compass needle points to true north. If you're east or west of 0° declination, the compass is not in line with true north.
- A diagram on topographic maps shows whether magnetic north is to the east or west of true north and by how many degrees.
- You can correct for declination when you use a compass and a map to take a bearing, as described below.