Creating a campaign map in GIMP

This tutorial assumes you are using GIMP which is a free image manipulation tool (poor mans photoshop essentially). If you have any feedback feel free to let me know at admin@jsigvard.com or on reddit at /u/thewardvg. Below is my own campaign map I created with this method as an example of what your map could look like at the end of it.

Basic Outline

1. Create a new image. The resolution is up to you really. Personally I use 3000x2000. Its important to not go to small as you want to be able to label smaller settlements etc. without having the text be illegible.

2. Fill the entire image with black and use whatever way you prefer to draw a rough outline of white. Personally I use the "Free Select Tool".

3. Apply a gaussian blur. Filters -> Blur -> Gaussian Blur -> 200.0 Blur Radius. The radius can be changed up and down as you see fit, with a higher radius resulting in deeper "divets" in the coastline. You probably want lower if your are using a smaller resolution image.

4. Create a new layer and fill it with clouds. Filters -> Render -> Clouds -> Solid Noise -> Set Detail and the sizes to maximum.

5. Adjust the brightness of the cloud layer. Colors -> Brightness-Contrast -> Turn brightness to about 80.

6. Select the layer with your blurry coastline and move it above the layer with noise, then set the mode (Dropdown at the top of the layer window) to Multiply and merge the two layers by right clicking on the top one, which should be the blurry outline of your continent, and click "Merge Down". You should now be left with a single layer looking somewhat like the image below.

7. Go to Colors -> Threshold and adjust the sliders till you like the result. Keep in mind that if massive lakes appear inland where you don't want them, you can easily fill them manually afterwards.

8. Chose the Select by Color tool (finger pointing to red), select the black and press delete. You now have a layer of free floating islands.

9. Select the white, chose the Bucket Fill tool (paint bucket), tick "Fill whole selection" and fill it with green. Make a new layer below the islands and fill it with blue.

10. Now you can go over it manually, removing any small islands by erasing them or lakes by filling them with green. This is also where you will want to draw rivers large enough to be seen at the scale your map is representing. Small rivers only a few pixels wide will look messy by the end so better to save those for more regional maps, or simply ignore them. And if you do draw rivers, always remember, rivers join up on the way to the ocean, they don't split. As an optional step to keep organized, name your blue layer "Water" and green layer "Land".

Continent Border

These changes are very minor on their own, but adds to the clean look of the final product

11. Right click on your land layer -> Alpha to Selection. Now make a new layer and name it "Border". Make sure you still have the shape of the lands selected while having this new empty layer selected and go to Select -> Grow -> 1 px. Now that your selected is slightly larger than the land it is time to get rid of those hard edges. Go to Select -> Feather -> 3 px. Now fill the entire area with black.

12. Right click on your land layer again -> Alpha to Selection. This time we will do the inverse, so go to Select -> Shrink -> 1 px, followed by Select -> Feather -> 3 px. Now, making sure you have the Border layer selected, hit delete. Change the Opacity (Slider above the layers) of the border layer to 30.

13. Now to add some detail to the water. Make a new layer and call it "Shallow". Right click on your land layer -> Alpha to Selection. Grow your selection by 10 px, and then feather it by 50. Now fill the new layer with white, and move the layer to be below Land and Border, but above water. Change the layers opacity to about 25, to get a nice gradiant from water to land.

14. To add some height to the map, duplicate the entire land layer by right clicking it and hiting duplicate. Alpha to Selection on your copied land, and paint it completely black. Select the Move Tool and move the layer down about 3 pixels (just click the down arrow 3 times) and put the new layer behind your actual land and rename it "Shadow Cliffs". Then change its opacity to about 40 or so.

These follow two steps are somewhat optional and only really a benefit you if your map will be high resolution in the end. But its a nice touch regardless.

15. Now that you should know how to do most of the basics, I'll stop explaining every button press. So, Make a new layer, Alpha to Selection on Land again, Grow the selection by 3 and fill it with black, then shrink the selection again by 1 and delete. You should now have a thin black line running along the coast slightly out in the water.

16. Repeat the previous step on another new layer, but grow by 6 rather than 3. Now you should have 2 lines, each on a different layer. Change the opacity of these layers down to about 20 and 10, or whatever you feel looks right. Once you are happy with it, merge the two layers together and name it "Waves"

Weathering