map generators

The tabletop RPG Dungeon World has a maxim for collaborative storytelling: “draw maps, leave blanks”. In truth, maps are all blanks. Even when they’re full of names and symbols, those symbols are merely pointers to meaning that may not be available. Gaps where our imagination is often happy to supply its own answers in terms vague yet fantastical. Everything on a map, every name, every islet and promontory and every curious shape in the coastline is a blank, one that could be filled with anything; in this space, some part of my heart wants to find something so marvelous and incongruous that it transforms the way I think about reality.

I started investigating map generators for a strategy game I wanted to make, but quickly found myself more concerned with simulating more earthlike and engrossing landforms than with any other element of the game. Most of my experimentation was centered on the use of Perlin noise heightmaps, or something like it, but this never fully satisfied me. Perlin noise produces interesting coastlines, but never arcing mountain ranges or smooth rolling plains, or archipelagos that are anything more than incidental. Anomalous inland seas crop up wherever the sea level dips below 0 (and only there), and continents (if they can even be called that) have erratic, fractal profiles that are inconducive to drainage. Despite my best efforts, I was never able to solve all these problems, though I still hope to someday. In the meantime, I did complete some other interesting experiments, including:

  • Creating sharper mountains and smoother plains through deposition erosion models

  • Filling depressions and forming lakes with the Planchon-Darboux algorithm

  • Establishing a less boxy structure with Voronoi tesselation

  • Simulating climate/biomes and human geography (mostly using Perlin noise, and A* for roadbuilding)

In the future, I would love to play with models that simulate plate tectonics (such as this classic by Lauri Viitanen), or explore novel methods that combine techniques to ensure the existence of key features. For now, however, maps are on the back burner.