Heliocentric Hubble distances and relative uncertainties against the primary distances of CF4-HQ galaxies. Left panel: Heliocentric Hubble distances $D_{\mathrm{H}}^{\mathrm{h}}$ versus primary distances D_p for 1866 galaxies from CF4-HQ. The galaxies are color-coded by the primary distance methodology as given in the legend. The solid black line is the one-to-one relation. The bottom panels show the residuals around the one-to-one line calculated as $(D_{\mathrm{H}}^{\mathrm{h}}-D_{\mathrm{p}})/D_{\mathrm{p}}$. We restricted the y-range to [ − 1.5, +1.5]. Right panel: Relative error on heliocentric and local-sheet Hubble distances, CF4 distances, and NAM distances versus primary distance. See Sect. 2.3 for details.