Hello, I was thinking about a Pokemon hack that would span over the Hoenn, Johto and Kanto regions. However, when I began too look into this, I realized something kind of interesting.
In this image, you can see that Kanto and Johto both span over the regions of Honshu in our equivalent of Japan, while Hokkaido represents the Sinnoh region. However, when I looked at the map of Hoenn in game, I noticed that it does not match up with Kyushu.
In the top-most map, you can clearly see that the Kyushu islands has two that are close to the mainland near the north side. The mainland on the south side is much wider, and has small islands on the west of it. This is the opposite on the Hoenn map. Thus, Hoenn is entirely upside-down!
So basically, I found out that in order to make my map and use the map of Japan as a base, I now have to flip the entire Hoenn region! What a pain.