Open street maps, I know it isn't quite what was asked, but it requires connection to be used and it sends maps chunks as images.

not if you download all the chunks and render them from localhost :D

@Parzi that works if you don't need to move the map or change zoom, else you need soooo many chunks. :D

@NarkoCat well, i mean

will you really need any more than like a 50 or 100 mile radius from home? and its not like you'll need super high up chunks, not many people zoom out to the state/province or country level, and pmuch no one zooms out to continent level unless it's lost track of you

@Parzi I had a project where we didn't opt in openstreetmaps because we needed world map and zoom into multiple parts of the world. And it would be run on a offline machine, so basicly we would need to host half of their chunks.
PS the zoom would need to be smooth.