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Appendix A. Determining True North and Wind Sensor Orientation
A-3
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/geomagmodels/Declination.jsp
. 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 (FIGURE
). Click the
Calculate button to get the magnetic declination.
FIGURE A-4. NOAA web calculator
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.