Figure 3:

Maps showing the maximum distance to the horizon from the surface of the Moon. Computations were done at 10 million points evenly distributed over the Moon’s surface. a: near-global map (80^○S to 80^○N), with a decimation factor for the points plotted of 33. b: zoom of a around craters Campbell and d’Alembert, but at full resolution. c/d: North/South polar regions (80^○−90^○ latitude) in polar steregraphic projection, at full resolution.