Redesigning the Setting: Drawing the Satellite View Map, 6

Creating the Land Height Map 

Creating the height map is probably the most important step for creating the map. This is what will give depth and height to your map and make the different geographical features identifiable. We are going to ultimately create 2 height maps, one for the land and one for the sea. This post concentrates on the Sea. By and large we are just going to duplicate the steps in Arsheeh's Eriond Tutorial for GIMP and Wilbur that was found at the cartographers guild. (Credits for this goes to him.)

Generating Clouds & Random Shapes

Create a new white layer above your outline and name it “Clouds 1”.

Layers > New Layer > White (Name "Clouds 1")

On that layer render a set of Difference Clouds. Set the Detail to 15 and (assuming a 3400x1700px size) the X and Y Size to 16.

Filter > Render > Clouds > Difference Clouds > Detail 15 ; Size 16

Create a new layer above Clouds 1 and repeat this step, only this time use a different seed for the Clouds. Name the new layer “Clouds 2”. Set the layer mode of Clouds 2 to Difference.
Layer > New Layer > White (Name Clouds 2) > Layer Mode (Difference)
Filter > Render > Clouds > Difference Clouds > Detail 15 ; Size 16

Right Click on Clouds 2 layer and select New From Visible and name the new layer "Difference 1"
Right Click on Clouds 2 > New From Visible (Name Difference 1)

Repeat this process. Create a “Clouds 3” and a “Clouds 4” layer (above the Difference Clouds 1 layer). Set the opacity of Clouds 4 to Difference and then create a New from Visible layer named “Difference Clouds 2”.

Repeat the preceding steps to make Difference 2

Next move the Difference 1 layer up in the dialogue to just below Difference 2.

Layer (Difference 1) > Raise layer (to just below Difference 2)

Land Clouds

Now set the layer opacity of the Difference 2 layer to Difference and then create a New from Visible layer right above it named “Land Clouds”. As the name implies, this layer will serve as the base clouds layer for our map. The picture captioned 'Land Clouds' should give you an example of what this looks like so far.

Layer (Difference 2) > Layer Mode (Difference)

Layer (Difference 2) > New from visible (Name Land Clouds)

Next we are going to generate cloud patterns to be used for mountains. To do so, follow the instructions given below. This should give you a set of clouds similar to that of the picture captioned 'Mountain Clouds'

Mountain Clouds

Layer (Land Clouds) > Hide Layer

Layer (Difference Clouds 2) > Layer Mode (Addition)

Right Click on Difference Clouds 2 > New From Visible (Name Mt. Clouds)

Colors > Invert. Set Layer opacity to 90%

Now that we have our cloud patterns we will isolate the Land Clouds with the map outline channel; but we'll deal with that in a future post.