[paradoxharbinger]

that would be a good place to start for part of, but you have to ensure that it makes sense with how the map looks. at least one of the provinces would have to be mountain terrain. there might be more conditions that have to be satisfied for the image to make sense with what map file says.

btw, adding a new layer to the heightmap for lakes should not be too difficult, and may actually be able to replace one of the others. in that case, there would be little time cost for adding it, meaning maps would only take slightly longer to generate. this is on the back burner for now.