The actual word I came up for this was chain mapping, as in ''travail ŕ la chaîne'' in French or assembly line in English.
The principle is different than the community projects like Guild World, Guild City and Guild Dungeon.
Instead of having several people mapping each a different plot, you have several people working on the same map.
This means they have to work with the same software.

Ideal, each team would be small with only 2 or 3 people.
One person would start the map and pass it to the other person after a certain number of days.
The second person does and same and cycle continues until the map is finished or the team run out of time.

I'm aware there might be issues, so it needs to be flexible.

This might be a good learning opportunity as it allow people to see how others are doing.