[Award Winner] Using GIMP to Create an Artistic Regional RPG Map

[RobA]

Post 6: Create the sea. (in the beginning...)

To make the ocean/water (and the base contour for the land as well) a two layer variant of the three layer sandwich will be used.
Copy the “Land Mask” Layer, and rename it “Sea Shape”. Apply a Gaussian Blur (Filter->Blue->Gaussian Blur) large enough to eliminate the absolute black and whites of the image. In this case, I used the same size as the image (500px).


Create a new layer and call it “Sea Noise” Fill this with Clouds (Filters->Render->Clouds->Solid Noise) set to a low size (3) and detail of 15, reseeding the random number. Set the layer blend mode to mode to Overlay, then merge it down with the “Sea Shape” layer by right clicking on the layer and selecting “Merge Down”.


Duplicate this layer and rename it “Sea”. Add a layer mask by right clicking on the “Sea” layer, and selecting “Add Layer Mask”. When the dialog opens, select “Channel” (By default it should have the “Land Mask” channel shown and check “Invert”. Click Add.


Nothing much will appear to have happened, but there will be a mask next to the layer thumbnail:


Layer masks act like filters that let parts of the image “show though”. Areas where the mask is white will allow the layer to be visible. Areas where the mask is black will be transparent, and the various shades of grey will be varying degrees of transparency. Now right click on the “Sea” layer and select “Apply Layer Mask”. This will remove pieces of the layer based on what was showing through the layer mask. Here I have made all the other layers invisible to see the result:


Also, check out the histogram….that is where we start next.