PostGIS is a set of GIS based extensions for PostgreSQL databases. As PostgreSQL is extensible, PostGIS is simply one of many extensions, but one of the most popular.
| Aspect | Description |
|---|---|
| Open Source | Released under the GNU General Public License (GPLv2 or later) |
| Documentation | Excellent documentation on the documentation site |
| Features | Many features rarely found in other competing spatial databases. See PostGIS Feature list |