A.1 Online magnetic declination calculator
The magnetic declination calculator web calculator published by NOAA’s Geophysical Data
Center is available at the following url:
www.ngdc.noaa.gov/geomag/calculators/magcalc.shtml
This web page calculates declination based on the latitude and longitude. You can look up your
site's latitude and longitude by entering the Zip Code or the Country and City, and then clicking
the Get & Add Lat/Lon button (
(p. 78)). Click the Calculate button to get the
magnetic declination.
FIGURE A-4. NOAA web calculator
(p. 79) shows that the calculated declination for Logan, UT is 11.78 degrees (11
August 2015). The declination for Utah is positive (east of north), so True North for this site is 360
– 11.78, or 348.22 degrees. The annual change is – 6 minutes/year or 6 minutes west per year.
Appendix A. Determining True North and wind sensor orientation
78
