Model field at a point by IGRF (IGRF-12) Please refer to: International Geomagnetic Reference Field: the 12th generation, Erwan Thebault, Christopher C Finlay, Ciaran ... http://wdc.kugi.kyoto-u.ac.jp/igrf/point/index.html
Please refer to: International Geomagnetic Reference Field: the 12th generation, Erwan Thebault, Christopher C Finlay, Ciaran D Beggan, Patrick Alken, Julien Aubert ... http://wdc.kugi.kyoto-u.ac.jp/igrf/