Garmin GPS II Owner's Manual page 83

Magnetic Heading Reference
The GPS II's heading information can be displayed referencing magnetic north
(auto or user-defined), true north, or calculated grid headings. The default setting is
automatic magnetic north, which is suitable for most applications.
To select a heading reference:
1. Highlight the 'heading' field (Fig. 77a), and press ENTER.
2. Select the desired heading preference, and press ENTER.
To enter a user-defined magnetic heading:
. 1. Select 'User Mag' and press ENTER (Fig. 77b).
2. Enter the degrees and direction of magnetic variation, and press ENTER.
REFERENCE
Fig. 77a
Fig 77b
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