Spatial distribution of galaxies over the area of sky considered here. Black dots mark the position of 4618 galaxies selected from SDSS. Coloured stars are the DustPedia sample galaxies – E/S0 (red), Sa/Sb (yellow), Sc/Sd (green) and Sm/Irr (blue). The black ellipse marks the virial radius of the Virgo cluster centred on M87. The orange ellipse is the size of the density contrast aperture (radius of 1.5 Mpc, see Sect. 4.2) at the sample median distance of 19.9 Mpc. On the right there is an expanded view of the Virgo cluster.