Fig. 2
From: First results from the Swarm Dedicated Ionospheric Field Inversion chain
Map of magnetic observatories, the data of which were used as inputs of the DIFI algorithm (blue dots) or as independent data when validating the DIFI model (red dots). Quasi-dipole latitudes \(\pm 55^{\circ }\) are shown as dashed black lines. The magnetic dip equator is depicted as a thick black line