Histogram of gravitational slope angles for the five regions, with one color per region, in logarithmic scale (left) and linear scale (right) for the Y axis. The values are normalized so that the sum of all Y values equals 1. Each region has a unique distribution of gravitational slopes, related to its unique topography. All regions cover a widee range of slopes from 0° to almost 100°. The gravitational slopes were derived from the SPC shape model (Jorda et al. 2015).