pass’s magnetic north. Notice that the map below shows magnetic north,
true north (T.N.), and grid north. (For the purpose of map-and-compass
work, T.N. should be ignored.) The degree of declination is also shown.
Because the bearing was established using the map’s grid line, the grid
north marking on the diagram dictates which direction the compass
housing should be rotated. If the diagram shows magnetic north toward
the left of grid north, turn the compass housing to the left (counter-
clockwise). If the diagram shows magnetic north toward the right of grid
north, turn the compass housing to the right (clockwise). In either case
you will rotate the compass housing the number of degrees indicated
on the map.
Keep in mind that magnetic north changes slightly each year. The
map will indicate how far it moves each year and how you can adjust for
the difference. The compass should now be adjusted for declination, and
will give you a true indication of what direction to travel.
Magnetic North DeclinationGrid NorthTrue NorthA topographical map showing declination.
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