How do I recreate this terrain effect?

[jeremysbrain]

Can anyone help me figure out the best way to create ridges and hills like in these examples or point me to a tutorial that does something similar? I have GIMP and Inkscape.

[Redrobes]

Thats called "Shaded Relief" and is usually created automatically by having the 3D height information from the ground instead of manually painting it in. But if your insisting on creating it manually then you start with a plain mid green background and lighten one side of the hill and darken the other in the same way that the sun will light it. In this case it seems to me that the top left is lighten and bottom right is darker. Also, it usually looks _wrong_ if you lighten up a map like that on the lower side of the mountains although physically this is just as possible because your normally stood upright and everything is lit from above.

If your creating hills of our own planet or can use earth data as a substitute for your terrain then you can download 3D height terrain from NASA and put it through some apps to render it out shaded relief. Alternatively you might be able to find some area of the world with just shaded relief hills rendered by someone with a free license and then you can use some of that on top of your own map. With GIMP you can add another layer to your map and use the "multiply" filter on the layer. Make the shaded relief a greyscale mostly white with a bit of light grey in the areas you want shaded dark.

Hope that helps.

[jeremysbrain]

Are there any good tutorials for doing shaded relief in GIMP?

[waldronate]

http://www.shadedrelief.com/ is a good resource for many such techniques for converting a heightfield such as a DEM or hand-drawn element into pretty shaded relief. Most of the techniques are not using The GIMP, though.

The GIMP's Bump Map filter (https://docs.gimp.org/2.10/en/gimp-filter-bump-map.html) should give good results. You should be able to put the bump map on its own layer and then blend that layer on top of your color layer using transparency. Using a straight multiply blend can only darken the colors, not lighten them.