Asmo made them. And yes it does use a lot of land, but Asmo builds one on top of the other, so that space is freed.
He has apparently worked out a way to “freeze” the maps.
Once the maps are moved from BigCity to Creative, they become static, because they aren’t compatible with multiverse. So, they won’t change after you capture them, once you move them to Creative
Wow, you got me! It’s in BigCity (since I have W/E there) and pretty easy to find on dynamap. If you have any requests for me to do for station names, fire away!