This mod allows you to place all terrain features, all improvements, wherever you want, without restrictions.
Once you have finished your map, remove the mod so the gameplay isn't affected.
Extra features: This (will) add more features, like city centers, islands, etc, for aesthetics and beauty of the map. These will offer no gameplay bonuses , with the only purpose to enbeauty the map.
These are intended only for screenshot maps, meaning, maps that will never be played, as you'll need to remove the mod before playing with, hence removing the addings with it.
Maybe I'll do a light version of this, so it can be playbale, but for now, no ...maybe.