Realistic Fantasy Maps, Part 1: Forging Mountains with Real-World Data
Welcome, fellow Kartographers! In this series, we’re going to dive deep into creating stunning, realistic fantasy maps, and our tool of choice for the heavy lifting will be the incredible terrain generator, Gaea.
But before we can sculpt majestic landscapes in Gaea, we need a solid foundation. The most convincing fantasy worlds borrow from the logic of the real one. So, our journey begins not in a fantasy realm, but here on Earth. In this first tutorial, we’re going to create our own custom digital “stamps” by turning real-world mountain ranges into brushes for GIMP or Photoshop (this tutorial will try to cater for both!)
This process is the key to laying down a quick, organic-looking continental heightmap that will serve as the base for our work in Gaea.
Want to skip to the map making?
If you want to just purchase some brushes and get straight to map making, I want to give a huge shout-out to a fellow artist, Joshua Goff Visual. He has created an extensive pack of brushes, which are the ones I use, for a reasonable price on his Patreon.
He also creates some absolutely stunning maps and offers a fantastic tutorial that shares a similar starting point to our method. His process also begins with creating an initial heightmap, but then takes it into a powerful (and free!) program called Wilbur, which is a great alternative if you don’t have a Gaea license but still want ot create high resolution maps. I can’t recommend his tutorial enough – it’s incredible value, even including the brushes you’ll need. If you’re interested in exploring that path, you can find his work and resources on his Patreon: Joshua Goff Visual on Patreon.
Step 1: Find and Download Real-World Heightmap Data
A heightmap is simply a greyscale image where value represents elevation: pure black is the lowest point (sea level) and pure white is the highest peak. We need to find a source for this data.
While there are many professional sources, one of the easiest to use is the Tangram Heightmapper.
Navigate to the Heightmapper: Open your browser and go to the Tangram Heightmapper.
Explore the World: You’ll see a map of the world. Pan and zoom to find a mountain range that has an interesting shape. The Himalayas, the Andes, the Rockies, or the Alps are all fantastic choices. You can create both mountain ranges or general terrain brushes. Just consider the scale of the brush
Position and Export: Center the most interesting part of the mountain range in the view. On the left-hand panel, click the Export button. This will download a PNG file of the heightmap in your current view. Increase the render multiplier for heigher resolution outputs
Step 2: Extract Your Mountain Range
Now we’ll head into GIMP (or your image editor of choice) to isolate the part of the map we want to turn into a brush.
Open the Heightmap: Open the PNG file you just downloaded.
Select an Area of Interest: Grab the Free Select Tool (Lasso). Draw a rough selection around the specific mountain range or peak formation you find appealing. Don’t worry about being perfect.
Feather the Selection: This is the most crucial step for making the brush blend naturally. A hard edge will look artificial when you stamp it. We need to soften the selection border.
In GIMP: Go to
Select > Feather.... A good value to start with is between 50-100 pixels, depending on the size of your image.In Photoshop: Go to
Select > Modify > Feather....
Copy Your Selection: Once feathered, copy the selected area to your clipboard (
Edit > CopyorCtrl+C).
Step 3: Create your Brush
With our feathered mountain range on the clipboard, we’re going to create a brush that is pure white, using our heightmap data to control its transparency. This is the best way to ensure that only the high-elevation “white” data is stamped onto your map, giving you a clean foundation. We’ll also make sure we use all the available resolution from our download.
For GIMP Users
Create Image From Clipboard: Go to
File > Create > From Clipboard. This makes a new image from your selection on a transparent background. Let’s call this the “data layer.”Add a White Layer: Create a new layer above your data layer (
Layer > New Layer...). Name it “White” and fill it with solid white.Add a Layer Mask: Right-click your new “White” layer and choose
Add Layer Mask.... In the dialog, initialize the mask to Black (full transparency).Paste Heightmap into Mask:
Click on the thumbnail for your original “data layer” and copy it (
Ctrl+C).Now, click on the black mask thumbnail next to your “White” layer to select it.
Paste the data into the mask (
Ctrl+V) and anchor the selection (Ctrl+H).
Tidy Up (Optional but Recommended): You can now hide the original “data layer.” If you see any rough edges or areas you want to remove, you can select the mask thumbnail and paint on it with a soft-edged brush. Painting with black will erase parts of the mountain, and painting with white will bring them back.
Export as a .gbr file:
Go to
File > Export As...and name your file with a.gbrextension (e.g.,andes-brush.gbr).Save it in your GIMP brushes folder (find the path via
Edit > Preferences > Folders > Brushes).
Refresh GIMP’s Brushes: Open the Brushes Panel (
Windows > Dockable Dialogs > Brushes) and click the “Refresh brushes” icon.
For Photoshop Users
Create a New Image: Go to
File > New.... Photoshop should automatically use the dimensions of your clipboard data.Ensure “Background Contents” are Transparent.
Set the color depth to 16 Bit. Click Create.
Create a White Layer: Make a new layer and fill it with solid white (
Edit > Fill... > White).Add a Layer Mask: With the white layer selected, go to
Layer > Layer Mask > Hide All. This creates a black mask that makes the white layer invisible.Paste Heightmap into Mask: Hold Alt (Win) or Option (Mac) and click on the black mask thumbnail. Your canvas will turn white/black, showing you the mask. Now, paste your copied mountain range into it (
Ctrl+V).Tidy Up (Optional but Recommended): Click on the layer thumbnail to exit the mask view. You can now select the mask thumbnail and paint directly on it with a soft-edged brush. Painting with black will hide parts of the white layer, and white will reveal them, allowing you to perfect the shape of your range.
Define Brush Preset: With the layer selected, go to
Edit > Define Brush Preset.... Give your brush a descriptive name and click OK.
Step 4: Use your new Brush
Your new mountain range brush is now ready to use! It will appear in your Brushes Panel, likely at the bottom of the list.
In the next part of the series, we’ll take a heightmap created with these brushes and bring it into Gaea to begin the truly magical process of erosion and detailing.
Happy mapping!
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