Specifications

RAWS-P Remote Automated Weather Station
in Figure 9.3-3. Note that when a negative number is subtracted from a
positive number, the resulting arithmetic operation is addition.
For example, the declination for Longmont, CO is 10.1°, thus True North is
360° - 10.1°, or 349.9° as read on a compass. Likewise, the declination for Mc
Henry, IL is -2.6°, and True North is 0° - (-2.6°), or 2.6° as read on a compass.
FIGURE 9.3-1. Magnetic Declination for the Contiguous United States
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