Histograms of difference maps for line-of-sight velocity, ∆v_los, in upper panel a and the vertical component of the magnetic field strength, ∆B_los, in lower panel b. The histograms include pixels that have . This corresponds to 25% of all pixels. The differences are taken for different cases: Red line → straight VTF and reference map; blue line → normalised straight VTF and reference map; green line → rabbit VTF and reference map; black line → snap 1 and snap 2; yellow line → snap 1 and snap 11.