Top panel: median proper motion in Galactic longitude, μ_l, LSR, per pixel in Cartesian Galactic co-ordinates, for the disc RC sample shown in Fig. 8. Overplotted are the highest density contours from Fig. 8, highlighting the overdensity of the Galactic bar. The arrow highlights the direction of the solar motion used to correct the proper motion map. The large μ_l values close to the solar position point to a residual correction that may be necessary. Bottom panel: same proper motion map for the disc red-giant sample used in Romero-Gómez et al. (2019).