1. go to http://www.ngdc.noaa.gov/geomag-web/#igrfgrid

2. parameters:

Min Lat
Max Lat
Lat Step Size

Min Lon
Max Lon
Lon Step Size

Elev: 0km MSL

Magnetic component: Declination

Model: WMM (2014-2019)

Start Date: [today's date, or any date you want]

Step size: 1.0

Result format: CSV