Geos provides a spatial object model and fundamental geometric functions. it implements the geometry model defined in the opengis consortium simple features specification for sql. functions provided include:

* spatial predicates (based on the de-9im model),
* overlay functions (intersection, difference, union,
symmetric difference),
* buffer,
* convex hull,
* area and distance functions, and
* topological validity checking
this package contains the c++ library. a c library is provided by the libgeos-c* package.