Have a map on the central server that everyone can update from, and edit.

I'd like to have a system where:
- users can keep their map up-to-date easily, and
- mappers can update the map easily.

The user part is mostly figured out - the mapper can download and reload certain areas fairly well. What's left to figure out is the mapping part.

Should several people be allowed to edit an area at once? Or one mapper per area? What if there's a conflict in the maps? How to make sure that only one person is mapping an area?

Need to figure that logic out.