Variation of the mean of the velocity prior over the Galactic sky at six different distances. The quantity shown is ﹩\sqrt{{v}_{\alpha * }^{2}+{v}_{\delta }^{2}}﹩, where v _α* and v _δ are the means of the two components of the velocity prior at the specified distance in each HEALpixel. In each distance slice, the color bar covers the full range of velocities plotted, and it is different for each slice.