Results of the Fe abundance inversion for the reference test case (4 circular spots, 7 Fe i lines, including magnetic field). The star is shown at five rotation phases, which are indicated above the spherical plots, and an inclination angle of i = 60°. The spherical plots show a) the true abundance map; b) reconstructed abundance map; c) difference map. The contours over the difference map are plotted at ±0.3,0.6,0.9 dex. The thick line and the vertical bar indicate positions of the rotational equator and the pole, respectively. The colour bars give the local abundance in log N_Fe/N_tot units.