How best to create a satellite map and mask

[JohnLoftyWiseman 1]

So now I've finally got up to the stage of creating a satellite map and mask for my terrain. I have my height map (as a .xyz). I've imported it into Visitor 3 and added a few buildings, roads, and plants. I've then exported the different layers (building layer, plants layer, terrain layer, and roads layer) as EMFs, and converted them to PNGs, before importing them into Paint.net (I don't have Photoshop but I'm thinking of using Gimp), and edited the layers so that they all lie on top of the terrain layer (the background at this point is not visible), the result of which can be seen here. (You'll notice that the few objects I've placed are located in the lower left hand corner of the image; I'll add more in future, but this is just to begin with.) The biome is temperate forest, just for reference.

So now I need to add the textures to make the complete satellite map, but unfortunately I have little to no experience using image editing programs to this level. Is it a case of actually adding images over and over and blending them, or is there a way to change a particular colour from the SurfaceMapLegend to a specific texture (which would be way more preferable)? Do images have to be smudged or blended in some way? From the tutorial I'm currently going through, the end result should look something like this, but with my terrain. As of now I have no idea how to get anywhere near that stage, let alone creating the mask, which according to that same tutorial should look a little like this, again with my terrain though. If anyone could give some advice about how to undertake these tasks, I would be very grateful.

Thanks again for all advice. The help I've received so far has been extremely helpful indeed.

[jakerod 254]

I recommend using L3DT. It's free but it can only export images of a certain size unless you buy the professional edition for $35. If you plan on doing a lot of terrain stuff in the future I recommend buying it. It is pretty awesome. There is also a 30 day trial option for the professional edition. It is fairly simple to use. Essentially you import a heightmap or create one. Then you make a water table. After that you do an attributes mask and you can choose from a range of climates. Then from there you can make a sat image. There is also the option to import an attributes map. It isn't always good for doing details like roads but for a basic here's grass, beach, cliffs, dry grass, etc. it is quite useful. Details can be achieved in Gimp and probably Paint.net although I have never used Paint.net.