S2 Geometry

s2geometry is Google’s open source geometry library designed for representing, analyzing, and manipulating geometric shapes on a sphere rather than a flat plane. This makes it particularly suited for applications involving geospatial data, such as mapping, spatial indexing, and geographic information systems (GIS). The library provides a robust mathematical framework for spherical geometry, allowing developers to work with polygons, points, and regions on the Earth’s surface using consistent and precise algorithms. Unlike traditional 2D geometry libraries, S2 ensures accuracy over large scales by modeling the globe directly, avoiding distortions caused by map projections. The project includes core C++ support, optional Python bindings, and integrations with Bazel and CMake for flexible builds. It relies on Abseil, OpenSSL, and googletest, and is tested across major platforms.