s2rst

A Rust port of Google's S2 Geometry library — robust, efficient spherical geometry on the unit sphere (S²).

S2 represents points, regions, and shapes on the surface of a sphere using unit-length 3D vectors rather than latitude/longitude pairs. This avoids singularities at the poles and discontinuities at the antimeridian, and makes geodesic-edge operations behave consistently everywhere on the sphere. It also decomposes the sphere into a hierarchy of cells ordered along a Hilbert space-filling curve, enabling fast spatial indexing and queries.

Installation

[dependencies]
s2rst = "0.1"

Quick example

use s2rst::s1::Angle;
use s2rst::s2::{Cap, LatLng, Region};
use s2rst::s2::region_coverer::RegionCoverer;

// Define a spherical cap (disc) centered on Paris.
let center = LatLng::from_degrees(48.8566, 2.3522).to_point();
let cap = Cap::from_center_angle(center, Angle::from_degrees(0.5));

// Approximate the cap with a covering of S2 cells.
let coverer = RegionCoverer::new().max_level(14).max_cells(8);
let covering = coverer.covering(&cap);
assert!(!covering.is_empty());

// Every point inside the cap is contained by the covering.
assert!(covering.contains_point(center));

Modules

The crate is organized into modules corresponding to the mathematical spaces they operate in. Most users will work primarily with the types in s2.

Module	Space	Key types
`r1`	Real line (ℝ¹)	`Interval`
`r2`	Euclidean plane (ℝ²)	`Point`, `Rect`
`r3`	Euclidean 3-space (ℝ³)	`Vector`, `PreciseVector`, `ExactFloat`
`s1`	Unit circle (S¹)	`Angle`, `ChordAngle`, `Interval`
`s2`	Unit sphere (S²)	`Point`, `CellId`, `Cell`, `Loop`, `Polygon`, and many more

Feature flags

serde — Serialize/Deserialize implementations for the core types.
geo-types — conversions to and from the geo-types ecosystem.

License

Licensed under the Apache License, Version 2.0, the same license as the upstream S2 geometry library this project is derived from. See the bundled LICENSE, NOTICE, and AUTHORS files for the full text and attribution.