Fig. 1From: The value of using measurements of geomagnetic field in addition to irradiance and sea surface temperature to estimate geolocations of tagged aquatic animalsEarth’s main field showing the observed intensity contours, the magnetic and geomagnetic poles and the geographic pole, around which the earth rotates [7]. The lines of force are indicated on the above insert and the best-fitting geocentric dipole based on the International Geomagnetic Reference Field (IGRF) on the lower insertBack to article page