PostGIS adds support for geographic objects to the PostgreSQL object-relational database. 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".

Cinaps is a trivial metaprogramming tool using the OCaml toplevel. It is based on the same idea as expectation tests. The user writes some OCaml code inside special comments and cinaps make sure that what follows is what is printed by the OCaml code.

pgTAP is a suite of database functions that make it easy to write TAP-emitting unit tests in psql scripts suitable for harvesting, analysis, and reporting by a TAP harness, such as those used in Perl and PHP applications.

OGR is the vector half of the GDAL spatial data access library. It allows access to a large number of GIS data formats using a simple C API for data reading and writing. Since OGR exposes a simple table structure and PostgreSQL foreign data wrappers allow access to table structures, the fit seems pretty perfect.

pgRouting extends the PostGIS/PostgreSQL geospatial database to provide geospatial routing and other network analysis functionality.

pgRouting extends the PostGIS/PostgreSQL geospatial database to provide geospatial routing and other network analysis functionality.