What information is in your "maps"? Is it just the outline of continents or other geographic areas, or does it include representations of mountains and other features? Does it include any description of *height*? If these things are represented in the map somehow, you would need to determine how to translate them into Terragen features and functionality, specifically terrain displacement. It can be quite challenging to do this with any program, including Terragen, and get a realistic result out of it. It would help to see the maps (or an example of one) to give you more feedback.
- Oshyan