I’m talking more about maps on the scale of a country or continent than a city or dungeon here.

How do you show that a mapped area has sections of more positively or negatively (spherical or hyperbolic) curved space, besides crocheting the map and actually adding more or less surface area to those parts? Actually, that might not be a terrible idea.

My only other idea is to add a grid over the whole map and distort it in those places, make it look pinched or like a bubble in the map. Is this something anyone here has already found a good solution for?