PostGIS

"An open source software program that adds support for geographic objects to the PostgreSQL object-relational database. PostGIS follows the Simple Features for SQL specification from the Open Geospatial Consortium (OGC).

The features include:

• Geometry types for Points, LineStrings, Polygons, MultiPoints, MultiLineStrings, MultipPolygons and GeometryCollections.
• Spatial predicates for determining the interactions of geometries using the 3x3 DE-9IM (provided by the GEOS software library).
• Spatial operators for determining geospatial measurements like area, distance, length and perimeter.
• Spatial operators for determining geospatial set operations, like union, difference, symmetric difference and buffers (provided by GEOS).
• R-tree-over-GiST (Generalized Search Tree) spatial indexes for high speed spatial querying.
• Index selectivity support, to provide high performance query plans for mixed spatial/non-spatial queries.
• For raster data, PostGIS WKT Raster (now integrated into PostGIS 2.0+ and renamed PostGIS Raster)

The PostGIS implementation is based on "light-weight" geometries and indexes optimized to reduce disk and memory footprint. Using light-weight geometries helps servers increase the amount of data migrated up from physical disk storage into RAM, improving query performance substantially."

https://en.wikipedia.org/wiki/PostGIS

http://postgis.net/