Teragon is mainly for making random maps, though you can import a heightmap and work from there. Doing so requires a lot of effort because most real world heightmaps are 8 bit instead of 16 bit, requiring a lot of manual work to smooth out the Minecraft terrain that 8 bit creates. You might find someone to make that for you, but it isn't a simple thing. You will be best off asking for help in a map making or modding discord channel, where there is a faster chance of someone who will help you with that. They may or may not use Teragon with the real world heightmap, depending on their preferences, but that doesn't really matter. But perhaps someone reading this thread will help.