how can i get good maps like this:
Well, the texture there seems to have been generated in Terragen (rather quickly I think). That means that the texture is made up mostly of height-based information plus a bit of noise, or slope data for snow.
So to get texture maps like those you can use the height selector and slope selector devices to make “masks” for these areas. If you want to add a bit of noise in a way similar to TG, you can combine the terrain with a perlin noise before the passing it to the selector devices…
That should do the trick.