Filter
Top Products
Section 1. Preparation and Siting
1-9
Geographic Alt. CGM IGRF Magnetic Field Dipole
Lat. Long. (km) Lat. Long. H(nT) D(deg) Z(nt) Lat. Long.
42.03 248.15 0. 49.80 311.06 20608. 14.417 50505. 49.68 312.14
Magnetic declination is bold in this example to show its location in the table. A
positive declination is east, while a negative declination is west. The
declination in this example is 14.417 degrees. As shown in Figure 1.4-1, the
declination for Logan, UT is east, so True North for this site is 360 - 14.417, or
345.5 degrees.
FIGURE 1.4-2. Declination Angles East of True North Are
Subtracted From 0 to Get True North
FIGURE 1.4-3. Declination Angles West of True North Are
Added to 0 to Get True North