PostGIS

Abstract

PostGIS is a spatial database extension for the PostgreSQL object-relational database. It is certified as a compliant “Simple Features for SQL” database by the Open Geospatial Consortium (OGC). PostGIS adds geometry data types and spatial functions to the PostgreSQL database. The supported geometry data types are “Points”, “LineStrings”, “Polygons”, “MultiPoints”, “MultiLineStrings”, “MultiPolygons” and “GeometryCollections”. Spatial functions enable the analysis and processing of GIS objects. Examples are measurement functions like “Area”, “Distance”, “Length” and “Perimeter” and spatial operators like “Union”, “Difference”, “Symmetric Difference” and “Buffer”. Topological relationships, like “Equals”, “Disjoint”, “Intersects”, “Touches”, “Crosses”, “Within”, “Contains” and “Overlaps” ,are processed by the Dimensionally Extended Nine-Intersection Model (DE-9IM). PostGIS and PostgreSQL are open source. PostGIS is released under the GNU General Public License and PostgreSQL is released under the BSD license. The functionality of PostGIS is comparable to ESRI ArcSDE, Oracle Spatial, and DB II spatial extender.