Mean angular error of the reconstruction (see Fig. 1) as a function of all possible arrival directions on the northern hemisphere for the case of a UHECR with a rigidity r_* = 5 × 10¹⁹ eV. Panel a: magnetic field data consisting of local information with the LoS component are projected out (scenario A). Panel b: magnetic field data consisting of local information with the measured LOS component (scenario B) Panel c: as in the top left panel, but the data are supplemented by integrated LOS data (scenario C; see Fig. 6). The red and orange lines on the color bar indicate the maximum and mean values of the map, respectively.