Generating a world in Gimp, Part 1: Land and Shallows

By Jesse Morgan

This is a work in progress on how to create a nice, quick worldmap.

  1. Create a new image in gimp, 1200×800
  2. Delete the background layer because it’ll just get in the way.
  3. Create a new layer group
  4. Create a new Transparent layer in the group called “noise”
  5. Use Filter->render->cloud->solid noise with the following settings:
    1. random seed 1056316098
    2. detail 15
    3. turbulent
    4. x,y= 4.0,4.0

You should end up with something like this:

Now, Lets make some land.

  1. Create new layer above that, fill color #a4a3a3, set Mode to addition, then disable it. Name it “Shallows addition”
  2. Create new layer above that, fill color #888888, set Mode to addition. Name it “Land addition”
  3. Clone that layer, set Mode to grain merge
  4. Create new layer above that, fill color #000000, set Mode to burn
  5. This should give you a nice group of islands and the shallows around them.

By switching back and forth between the addition layers, you can create outlines of both the land and the shallows:

  1. Enable the shallows addition and disable land addition
  2. Click on the layer folder grouping
  3. Use select by color and select the black area
  4. Click on the solid noise layer
  5. Press delete. This should make a majority of the background clear
  6. Enable the land addition and disable shallows addition. This should leave you with white land, black shallows and clear ocean.
  7. Click Select->None
  8. Right click on the layer grouping and merge visible layers.

You now have a two-tone map:

Now to split it up.

  1. select by color and click on a white area
  2. create new transparent layer,
  3. fill with #7c674f
  4. click on 2 tone layer
  5. hold shift and click on black section
  6. create new transparent layer,
  7. fill with #aeb0ff
  8. click select->None
  9. On the two tone layer, fill with #202261

You now have a 3 layer image, one of solid oceans, one of shallows, and one of land.

Lets fuzz out the shallows:

  1. switch to shallows layer

  2. color select shallows

  3. filter->render->clouds->difference clouds

    1. seed: 1056316098
    2. turbulent
    3. detail 15
    4. x,y=4,4

And lets add a little texture to the base water:

Select the base ocean layer
filter->render->clouds->fog
Set the color to #050755
turbulence 3.0
opacity 60%
merge newly created fog layer down.

filter->render->clouds->fog
Set the color to #4043a9
turbulence 3.0
opacity 60%
merge newly created fog layer down.

And there we go, the final, fullsize image (click to embiggen):