The height map is usually the hard bit and that post you quoted was the method I use to make the height map. Normally there are apps about which generate random heights which lead to terrain but that wont fit into a predefined space like we had for this challenge / community world section.
Once you have the height map / topo then its up to you what you want to do with it. I have a little app which can take the height map and show it in 3D. I dont have a windows copy of that locally right now but I called it DragonFlight. But there are many other ways to view a topo in 3D not least by using Blender and importing it and doing a displacement on a square which has a lot of polygons in it. I think there are posts about that on the forum somewhere.
For me personally, once I have the 3D height scaled to the correct real world sort of values then I use a programmable shader to tell it that stuff below 0 is under the sea then low values is sand then higher is dirt and grass then higher still is rocks and then at the top is snow and mountain tops. You can do that by hand using masks and Gimp. Its not too hard, but its easier if you have a tool to do that with. So most of what I did in this thread was done in 2D and then put into my DragonFlight with the height map to show it in 3D.
If your really wanting to get into the 3D terrain stuff then there are many apps specifically for this. We have Wilbur which does a great job of creating and importing height map terrain and fixing up issues that you get with randomly generated terrain - that one is free. Also Vue, Terragen, WorldMachine, L3DT, World-Creator, etc which I believe are all paid apps. But Blender is very capable and free and you can import your height map and texture into that just like I did and render out scenes similarly. And Blender is completely free so Gimp + Wilbur + Blender is the route I would go down if I didnt have my tool set.
Some of my tools I have uploaded and have as a service. Most of these are 2D and not specifically tailored to making 3D terrain but I could do one where you load in the topo and it renders out the preformatted shaded version with all of the under sea, grass, mountains etc. Anyway, here is the link to that thread with the instructions:
https://www.cartographersguild.com/s...ad.php?t=49031
Edit: Have a search around for posts like this:
https://www.cartographersguild.com/s...ad.php?t=36941
Or check out Blender Nation or YouTube blender videos showing how to do displacement maps.
(If anyone has done a good blender displacement tut here then post the link below).