In each case, we have manually selected between 30 and 40 individual segments of topographic profiles to homogeneously sample the studied areas. An average curve as well as curves at plus and minus one standard deviation were calculated from these datasets and are displayed in Fig. 4. The average curves are also displayed on Fig. 5, superposed in a single plot to facilitate the direct quantitative comparison. As expected, the MAS curves show monotonic and nearly linear decreases as baseline increases. Because they allow for a better separation of the influence of the different spatial scales, the MDS curves show more variety between the different planets and the different terrains, as previously shown by Kreslavsky and Head (2000) and Rosenburg et al. (2011). Most of the discussion in the rest of this paper is thus related to these MDS curves.