Tough part is working out a reasonable system so we know what colors/backgrounds go with what type of building
making sure that everyone can actually get useful information from reading the map. Contrasts are an accessibility thing: without good information, people can’t play the game. D8
I’m thinking that perhaps having an archetype building, such as sporting-goods, be the colored (cyan, here) arrow and related buildings (dojo & gym) using that color as a background might be one way to work. I’m not sure how effective that’d be though.