Magnetic declination

The field identified as North Reference is used to tell EddyPro what to use as North.

Use magnetic North simply instructs EddyPro to consider the reference North as magnetic North.

Use geographic North instructs EddyPro to compute the declination based upon the date and location (geographical coordinates). To accomplish this, EddyPro polls the United States National Oceanic and Atmospheric Administration (NOAA) web site for the correct declination. By default, EddyPro uses the current date, but you can specify the date in the drop-down menu. The website constrains access to future dates.

Note: An Internet connection is required in order to retrieve the magnetic declination from the NOAA web site. EddyPro uses the International Geomagnetic Reference Field (IGRF11) model, which is described here: You can compute declination online at the same website.