Other useful extensions
The extensions that we have described so far are all part of the PostgreSQL contrib package, which is shipped as part of the PostgreSQL source code. However, the packages that we’ve looked at here aren’t the only ones that are available in the PostgreSQL community. Many more packages allow us to do all kinds of things.
The number of modules is growing daily, and it is impossible to cover them all. Therefore, I only want to point out the ones I find the most important.
PostGIS (http://postgis.net/) is the geographical information system (GIS) database interface in the open source world. It has been adopted around the globe and is a de facto standard in the relational open source database world. It is a professional and extremely powerful solution.
If you are looking for geospatial routing, pgRouting may be just the thing. It offers various algorithms that you can use to find the best connections between locations and works on top of PostgreSQL...
