Hi i'm doing an illustration of a map, In Maya I've created an polygon plane and turned the subdivisions to max settings 50 width/ 50 height and assigned my first draft map texture to it, what I want to be able to do is raise/lower specific areas (valleys hills etc), I can do this with the default verts asigned after creating the plane but because they are spaced to far apart I start raising areas I dont want to, could someone suggest the best way to say:- raise a specific shape/area of hill, can I simply draw on extra verts around a shape and raise it that way? or do I just need to increase the number of verts on my plane?

I've include a first draft pic to (hopefully) show more clearly what i'm after.

Thanks for any help