What is PostGIS?

PostGIS adds support for geographic objects to the PostgreSQL object-relational database and is included in the Postgres Plus product suite. In effect, PostGIS "spatially enables" the PostgreSQL server, allowing it to be used as a backend spatial database for geographic information systems (GIS), much like ESRI's SDE or Oracle's Spatial extension. PostGIS follows the OpenGIS "Simple Features Specification for SQL" and has been certified as compliant with the "Types and Functions" profile.

PostGIS has been developed by Refractions Research as a project in open source spatial database technology. PostGIS is released under the GNU General Public License. Refractions Research continues to develop PostGIS, and have added user interface tools, basic topology support, data validation, coordinate transformation, programming APIs and much more. Their list of future projects includes full topology support, raster support, networks and routing, three-dimensional surfaces, curves and splines, and other features.

The PostGIS project can be found at postgis.refractions.net.