The tourists in the story start in a place called Port Roris and travel across what Clarke describes as a remarkably flat expanse of almost liquid-like dust. PyGMT actually has a built in function for downloading topographic Moon data (pygmt.datasets.load_moon_relief). The map on the left shows a simple shaded elevation map of the area of the moon that this book is allegedly based on (Sinus Roris), a large basaltic plain on the Moon's Northern Hemisphere. I also added a proposed location of the 'star port' in the book, Port Roris. The book doesn't specify exactly where it is but I put it on a solid rocky peninsula with good access to the flat dusty expanse. Youll notice that most of the elevation values on the Moon's surface are 'negative'. This is all relative to the datum used - on Earth the datum is based on sea level but since there's no water on the Moon they must use some other metric. The map on the right shows the 'flatness' of the same region, using a standard deviation function that inspects the elevation values of the surrounding pixels for each pixel. The lower the value, the 'flatter' the area. There's probably some other cool moon maps to make so I might have to read more moon books.