# libgeos/geos

Geometry Engine, Open Source

Repository: https://github.com/libgeos/geos
Canonical: https://ross.abutalabs.com/products/geos
Homepage: https://libgeos.org
Language: C++
License: LGPL-2.1
License Family: copyleft
Topics: c, c-plus-plus, cpp, geometry
Last push: 2026-08-20T17:11:21+00:00

## Health v2 (maintenance only)
Score: 98/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 98, release rhythm 98, longevity 100
- inputs: {"age_days": 5425, "days_push": 13, "days_rel": 13, "gap_med": 7, "n_releases_24m": 12}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1494, forks 419 (observed 2026-08-28T04:04:52.907389+00:00)

## What it is
GEOS is a C/C++ library for computational geometry on 2D vector geometries, implementing the OGC Simple Features standard. It is a port of the JTS Topology Suite and serves as the core geometry engine behind PostGIS, QGIS, GDAL, Shapely, and R's sf package.

## Use cases
- compute intersections, unions, and buffers on polygons
- check spatial predicates like intersects, contains, and within
- read and write WKT and WKB geometry formats
- build a spatial index (STR-packed R-tree) for fast lookups
- validate and repair invalid polygon geometries
- power spatial queries in a GIS or mapping application
- calculate distances, areas, and convex hulls of geometries

## When to choose
- you need a mature, battle-tested 2D geometry engine with a stable C API
- you are building geospatial software and want the same algorithms as PostGIS or Shapely
- you need thread-safe geometry operations via the reentrant C API
- you work with planar/Cartesian coordinate data and OGC Simple Features

## When to avoid
- you need geodetic computations on the Earth's ellipsoid - GEOS is strictly planar 2D
- you need 3D geometry operations
- you want a stable C++ API across versions - only the C API is ABI-stable
- you need raster or coordinate reference system transformations - use GDAL or PROJ instead

## Facets
- artifact type: library
- maturity: stable
- function: geospatial, math, sdk
- domain: developer-tools
- platform: cpp, c, cross-platform, windows
- tags: computational-geometry, gis, spatial-index, wkt, wkb, postgis, shapely, jts-port, ogc-simple-features, geospatial, algorithms, maps, linux, macos

## Member repositories
- libgeos/geos (main) score 98

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:52.907389+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T04:33:22.678600+00:00, confidence not recorded.
  - readme: https://github.com/libgeos/geos (fetched 2026-08-28T04:04:52.907389+00:00, sha 69dcdc7b51c8)
  - homepage: https://libgeos.org (fetched 2026-08-29T11:38:54.104482+00:00, sha ea34fb5a3f9b)
  - site_page: https://libgeos.org/usage/install (fetched 2026-08-29T11:38:54.106792+00:00, sha 8ebdd07aa709)
  - site_page: https://libgeos.org/usage/doxygen (fetched 2026-08-29T11:38:54.108420+00:00, sha 13e99a265778)
  - site_page: https://libgeos.org/usage/faq (fetched 2026-08-29T11:38:54.109962+00:00, sha d3ad86ff642b)
  - site_page: https://libgeos.org/usage/download (fetched 2026-08-29T11:38:54.111658+00:00, sha d9ecf63df887)
- Data as of 2026-08-30T08:39:29.467469+00:00.