Youre mad ,mapping is the worst thing ever, youll be stuck on it forever if your not careful, ask any graphic designer lol,

Antique maps (hi res, invented but based on actual things, you obviously cant get photos of them available anywhere much at a reasonable price) would have lots of uses including to print so theyd be pretty cool if you must do maps.

A good looking hi res map of middle earth lord of the rings tolkein might sell pretty well if you use all the right keywords so it comes up on a google search but make it really hi res so it can be printed.

Not sure of copyright though.