Top: histogram of the 33 812 183 combined radial velocities. The sampling is 5 km s⁻¹ per bin. Bottom: sky map of the median radial velocity. The image uses a Mollweide projection in Galactic coordinates (l, b). The Galactic centre is at the centre of the image, and the Galactic longitudes increase to the left. The sampling of the maps is approximately 0.2 square degree (healpix level 7). The limits of the colour bar have been set at −50 and +50 km s⁻¹ in order to highlight the median velocity variations in the disc.