Topographic maps are drawn to true north (North Pole), which is indicated by the grid lines on the map. However, a compass will always point 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, you're at 0° declination. Your compass needle will point to true north. However, if you're east or west of 0° declination, your compass will not be in line with true north.
To compensate for declination:
- Center the north arrow (the "N") of the compass dial along a north/south line of the map.
- Adjust the compass declination as the map indicates.
- Hold the compass level in front of you and rotate your body until the tip of the compass needle aligns with the "N" on the compass dial. The direction arrow on the base plate now points in the direction you want to go.