GEOS (Geometry Engine - Open Source) is a C++ port of the JTS Topology Suite
(JTS). It aims to contain the complete functionality of JTS in C++. This
includes all the OpenGIS Simple Features for SQL spatial predicate functions and
spatial operators, as well as specific JTS enhanced functions. GEOS provides
spatial functionality to many other projects and products.

WWW: https://trac.osgeo.org/geos