What is the difference between Overworld and BS-Overworld in dmaps?
BS Overworld
I don't know. I sometimes question about that too.
The BS version is half the size, and you can set areas to appear on the map, like have each dungeon location marked.
...these spaces show up like a compass point, but you set them by setting the map spaces in the dmap screen. In this way, you can have as many of them as you want.