Elevation maps

Elevation maps are a project I’ve been working on-and-off for a while. They’re basically height maps downloaded from NASA, stitched together, and then converted into a 3D printing file (.stl) which can then be printed. The prints take about 16 to 20 hours on my Creality Ender 3 Pro, but they’re really cool.

Fetching and interpreting the raw files is non-trivial for what I assume are bureaucratic reasons, but I’ve created a python wrapper that abstracts around the whole thing. For an altitude map of the southern part of South Africa, I just type:

uv --offline run create-png.py --bbox -33 18.175 -35 22 --drop-ocean 100

(why offline?¹, what’s uv?²)

And then I get out an image like:

Which I think is pretty cool. The --bbox argument takes a bounding box like top left bottom right, and the --drop-ocean will drop the ocean by some number of meters. This helps make the print look better and stops low-altitude regions from blending into the ocean, especially when your printer’s z-height is 0.2mm.

I can also zoom in closer to Cape Town:

uv --offline run create-png.py --bbox -33.85 18.275 -34.4 18.525 --drop-ocean 100

When they’re printed out, I think they are really cool:

3D print of Cape Town and the south-western coast of South Africa	Regular map showing cities and towns of the 3D printed region (© OpenStreetMap contributors)
3D print of a closer view of the Cape Peninsula, False bay, and Stellenbosch.	Regular map showing cities and towns of the 3D printed region (© OpenStreetMap contributors)

I’ve put some of these STL files up on cults3d and will soon put up some more, once I’ve gotten my 3D printer up and running, reach out if you’d like a discount code (:

Footnotes

1. As I write this, South Africa’s power utility is unable to generate sufficient electricity for the entire country, and so is shutting off the power for selected regions. See this project for details and a write-up of my open-source project that provides loadshedding information to the country. ↩

2. uv is like python3, pip, venv, and all other python tools rolled into one! Give it a go (: https://docs.astral.sh/uv/ ↩