// the find
HydroniumLabs/h3o
Rust implementation of the H3 geospatial indexing system.
A from-scratch Rust reimplementation of Uber's H3 hexagonal geospatial indexing system — not FFI bindings to the C library, but a native rewrite. Aimed at anyone doing geospatial work in Rust who wants WASM compatibility or a pure-Rust dependency chain.
No C dependency means it cross-compiles to WASM without the usual FFI pain that plagues the official bindings. The type system is used well — invalid cell indices are a compile-time concern, not a runtime panic. The test suite mirrors the reference H3 test vectors exactly (see tests/h3/), so behavioral parity with the C implementation is verified, not assumed. Fuzz targets cover the tricky edge cases like transmeridian polygons and pentagon cells that regularly break naive implementations.
523 stars is thin for infrastructure you'd bet a production system on — the bus factor here is real and the contributor graph is almost certainly one person. The README is sparse to the point of being unhelpful; there's no example of polygon-to-cells or compaction, which are the operations people actually reach for. No mention of performance numbers relative to the C library despite that being an explicit design goal — you'd have to run the benches yourself to know where you stand. The geom module (solvent/tiler) lacks any documentation, and that's the complex part most users will struggle with.