Arnis converts real-world locations into Minecraft worlds that players can explore. The open-source project draws on OpenStreetMap and other sources, and has recorded close to 900,000 downloads from GitHub since Louis Erbkamm began it in 2022. Around 70 contributors have helped develop it.
Erbkamm created the first prototype in about two weeks during a break from school. The project began as a personal experiment combining Minecraft with geographic data. He chose the German town of Arnis as a test location because its buildings, streets and waterways offered a range of features to try out. The project later took the town’s name, though Erbkamm says he has never visited it.
Arnis generates a selected area by querying OpenStreetMap for mapped features and using their coordinates and types to place elements in the game. Features that are not mapped cannot be generated. For structures that require more detail than map data provides, such as the Statue of Liberty or Christ the Redeemer, the project can convert 3D models into Minecraft blocks.
The project’s community has contributed translations into about 20 languages and developed major features. When Erbkamm considered moving Arnis from Python to Rust, he opened discussions on GitHub to gather feedback. Adding elevation also brought in geospatial specialists who offered ideas for the project.
Erbkamm is Arnis’s sole maintainer and reviews pull requests alongside his day job, often in the evenings or on weekends. He uses GitHub Copilot to review open issues and bugs, assess how many users are affected, trace problems through the codebase and help prepare fixes. He says the tool has also helped increase the amount of code review and documentation work.
For larger pull requests, Erbkamm uses the GitHub Copilot app to get an initial overview and assess performance. He also uses sub-agents to examine code areas that may be vulnerable to regressions and suggest edge cases for testing. Small errors, such as a miscalculation involving street lights, can significantly slow the generation of an entire city.
Erbkamm says one of his favorite uses for Arnis is in schools. Teachers have generated local areas for classroom activities, with students improving parks or playgrounds in Minecraft and comparing their work.
Recent releases have added the Moon and Mars. Erbkamm wants the project to remain easy to use while adding detail and reducing generation time, and hopes to see it used in more schools. Users can download Arnis from GitHub, select a place and starting point on the map, and generate a world to open in Minecraft. Missing features can be reported as bugs or added to OpenStreetMap.
Sources: GitHub Blog.