Histogram of z_phot of galaxies populating each cell with |z_phot, SOM − z_spec|/(1 + z_spec) > 0.15 (right panel of Fig. 6). The distribution is normalized by dividing the number of galaxies in each z_phot bin by the total number of z_phot populating the considered cell; the number is indicated by the letter N in the top left panel, and written in the same position in the others. Similarly, the cell number (CellID) is also given in each panel. The z_phot, SOM is represented by the dashed line, whereas dotted lines indicate z_spec measured during our program. The horizontal bar centered on the mean z_phot is the RMS of the histogram.