After some difficulties I managed to re-install the 3D map. Please see the menu for the link. The maps are still rendered in a different mode than I was used to have, I will see if I can change that.
Also, the city is in creative mode now and shares inventory with the flatlands. I hope that nobody lost their inventory because of that. If that is the case, I unfortunately cannot do a lot. The goal of this is to make the city world accessible as creative mode to elders and to let them help me build the new city.
Also, there should be no more problem with EXP and enchantments when going from survival to creative and back.