ViewingDale, the main app, isn't 3D and doesn't use height maps thats just a little free thing used to look at them which are spat out from the other free tool instant islands used to make some real basic land masses. You can grab that and use it without having to buy or do anything. It's closed source freeware. I also use height maps to texture up backdrops but I use a different (and unfortunately unreleased) tool for that.
The scroll locked thing you can do by either offsetting the draw list of lines to the same offset for the map and then rendering out a section of it. Or, and more usually, you render the whole screen and put it into a scrollable window which shows only part of it. If I were doing this sort of thing then I would use a 3rd technique which is similar to the second and use windows MFC classes and GDI to draw the bitmap and lines and then copy a section to a displayable screen bit. Tho no hard, theres still a lot to know to do it tho. Id still think you would be better off using perl. Install any V5 32bit version and then install the image magick module by typing:
Code:
ppm install http://www.bribes.org/perl/ppm/Image-Magick.ppd
and then you can write a script where in a line or two load a bitmap and draw stuff on it. It wont be very fast tho. You may find that wx does easy graphics. I know there is a wx opengl thing you can use so presumably that works under Python. I havent ever used it and tho GL is very fast its a bit of a chore loading and saving images with it.