Radial GSR velocities of northern (top) and southern (bottom) MIVC^± samples compared with Galactic longitudes l, left for the MIVCs⁻, right for the MIVCs⁺. The velocities of the individual candidates are given by the from the Gaussian decomposition of the H i survey data. The colour of each point encodes the absolute value of the latitude coordinate b of the candidates as indicated by the colour bar. The different lines show the modelled rotation velocities including a radial, vertical, and lagging velocity component as estimated by Marasco & Fraternali (2011). Their vertical height z = 1.6 kpc is assumed, for which the velocities are modelled at some heliocentric distances d and latitudes b as given in the legends. The solid, dashed, and dotted lines are for b = 20°, b = 50°, and b = 80°. The red, blue, magenta, black, and cyan lines are for heliocentric distances within the Galactic plane of d = 1 kpc, 2 kpc, 3 kpc, 4 kpc, and 5 kpc.