Vertical maximum excursion |z_max| versus [Mg/Fe] relation for the ES20 model. The grey points indicate stars within the Galactocentric region between 6 and 10 kpc and |z|< 2 kpc as reported in the astroNN catalogue. The contour lines enclose fractions of 0.95, 0.90, 0.75, 0.60, 0.45, 0.30, 0.20, and 0.05 of the total number of observed stars. The colour coding represents the total number of stars predicted by the ES21 model in that region. In the left panel, we draw model results considering a Gaussian error (see Eq. (5)) with standard deviation σ_Jz = 0.5 ⋅ J_z, whereas in the right one we assume σ_Jz = 1 ⋅ J_z.