Editing Magnetic declination (section)

=== Rotating dial compasses ===
[[File:Rotating Dial Compass.jpg|thumb|Baseplate compass adjusted for 10° west (negative) declination and a true north direction of travel]]
A magnetic compass points to magnetic north, not geographic (true) north.  Compasses of the style commonly used for hiking (i.e., baseplate or protractor compass) utilize a dial or [[bezel setting|bezel]] which rotates 360 degrees and is independent of the magnetic needle.  To manually establish a declination for true north, the bezel is rotated until the desired number of degrees lie between the bezel's designation N (for North) and the direction (east or west) of magnetic north indicated by the polarized tip of the needle (usually painted red). The entire compass is then rotated until the magnetic needle lies within the outlined orienting arrow or box on the bottom of the capsule, and the course heading (in degrees) is displayed at the base of the direction-of-travel arrow on the baseplate.  A compass thus adjusted provides a course bearing in relation to true north instead of magnetic north as long as it remains within an area on the same isogonic line.

In the image at the right, the bezel's N has been aligned with the direction indicated by the magnetic end of the compass needle, adjusted for local declination (10 degrees west of magnetic north).  The direction-of-travel arrow on the baseplate thus reflects a true north heading. 
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After determining local declination, a rotating dial compass may be altered to give true north readings  by taping or painting a small delta-point or arrowhead on the compass baseplate west or east of magnetic north pointing to true north on the compass bezel.  Other compasses of this design utilize an adjustable declination mechanism integrated with the compass bezel, resulting in true north readings each time the needle is aligned with the orienting arrow.