GEOS

GEOS is a complete C++ implementation of the functions and predicates defined in the OpenGIS "Simple Features for SQL" specification. It includes high quality implementations of all the important spatial relationships and operations, robust versions of all functions in the dimensionally extended 9 intersection predicate model, implementations of the operators, Buffer(), Union(), and Intersection(), and all other SFSQL functions including Area(), Length(), Centroid(), etc. Link Freshmeat