GEOS 1.0 Released!
The first release of GEOS (geometry engine, open source) has been released at https://libgeos.org/. Using the GEOS library, it is possible for PostGIS to perform all the operations in the OpenGIS Simple Features for SQL Specification.
That means that operations like Touches(), Contains(), Intersection(), Buffer(), Centroid(), Union() can all be supported. To try out PostGIS-with-GEOS, download the CVS snapshot of PostGIS and follow the directions in the README file carefully.