PostGIS ( ) is an open source software program that adds support for geographic objects to the
PostgreSQL
PostgreSQL (, ), also known as Postgres, is a free and open-source relational database management system (RDBMS) emphasizing extensibility and SQL compliance. It was originally named POSTGRES, referring to its origins as a successor to the ...
object-relational database. PostGIS follows the
Simple Features for SQL specification from the
Open Geospatial Consortium (OGC).
Technically PostGIS was implemented as a ''PostgreSQL external extension''.
Features
* Geometry types for Points, LineStrings, Polygons, MultiPoints, MultiLineStrings, MultiPolygons, GeometryCollections, 3D types TINS and polyhedral surfaces, including solids.
* Spheroidal types under the geography datatype Points, LineStrings, Polygons, MultiPoints, MultiLineStrings, MultiPolygons and GeometryCollections.
* raster type - supports various pixel types and more than 1000 bands per raster. Since PostGIS 3, is a separate PostgreSQL extension called postgis_raster.
* SQL/MM Topology support - via PostgreSQL extension postgis_topology.
* 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
R-trees are tree data structures used for spatial access methods, i.e., for indexing multi-dimensional information such as geographical coordinates, rectangles or polygons. The R-tree was proposed by Antonin Guttman in 1984 and has found sig ...
-over-
GiST
In computing, GiST or Generalized Search Tree, is a data structure and API that can be used to build a variety of disk-based search trees. GiST is a generalization of the B+ tree, providing a concurrent and recoverable height-balanced search tree ...
(Generalized Search Tree) spatial indexes for high speed spatial querying.
* Index selectivity support, to provide high performance
query plan
In general, a query is a form of questioning, in a line of inquiry.
Query may also refer to:
Computing and technology
* Query, a precise request for information retrieval made to a database or information system
** Query language, a computer l ...
s for mixed spatial/non-spatial queries.
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.
PostGIS is registered as "implements the specified standard" for "Simple Features for SQL" by the OGC.
OGC Implementing Product Details
Open Geospatial Consortium PostGIS has not been certified as compliant by the OGC.
History
Refractions Research released the first version of PostGIS in 2001 under the GNU General Public License
The GNU General Public License (GNU GPL or simply GPL) is a series of widely used free software licenses that guarantee end users the four freedoms to run, study, share, and modify the software. The license was the first copyleft for general ...
. After six release candidates, a stable "1.0" version followed on April 19, 2005.
In 2006 the OGC registered PostGIS as "implement ngthe specified standard" for "Simple Features for SQL".[PostGIS History](_blank)
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Users
Many software products can use PostGIS as a database backend, including:
* ArcGIS (via GISquirrel, ST-Links SpatialKit, ZigGIS, ArcSDE and other third-party connectors)
* Cadcorp SIS
* CartoDB
* CockroachDB
* GeoMedia
Hexagon Geospatial's (a division of Intergraph Corporation) GeoMedia Professional is a geographic information system (GIS) management solution for map generation and the analysis of geographic information with smart tools that capture and edit s ...
(via third-party connectors)
* GeoServer
In computing, GeoServer is an open-source server written in Java that allows users to share, process and edit geospatial data. Designed for interoperability, it publishes data from any major spatial data source using open standards. GeoServer h ...
(GPL)
* GeoNetwork (GPL)
* GRASS GIS (GPL)
* gvSIG (GPL)
* Kosmo (GPL)
* Manifold System
* MapInfo Professional
MapInfo Pro is a desktop geographic information system (GIS) software product produced by Precisely (formerly: Pitney Bowes Software and MapInfo Corporation) and used for mapping and location analysis. MapInfo Pro allows users to visualize, ana ...
* Mapnik (LGPL)
* MapServer
MapServer is an open-source development environment for building spatially enabled internet applications, built in the C language, and is widely known as one of the fastest Web mapping engines available. It can run as a CGI program or via MapSc ...
( BSD)
* Maptitude
* MapGuide (LGPL
The GNU Lesser General Public License (LGPL) is a free-software license published by the Free Software Foundation (FSF). The license allows developers and companies to use and integrate a software component released under the LGPL into their own ...
)
* OpenJUMP
Java Unified Mapping Program (JUMP) is a Java based vector and raster GIS and programming framework. Current development continues under the 'OpenJUMP'' name.
Features
As featured on the project's website:
* Platform independent ( Windows, ...
(GPL)
* OpenStreetMap
OpenStreetMap (OSM) is a free, open geographic database updated and maintained by a community of volunteers via open collaboration. Contributors collect data from surveys, trace from aerial imagery and also import from other freely licensed g ...
* QGIS
QGIS is a free and open-source cross-platform desktop geographic information system (GIS) application that supports viewing, editing, printing, and analysis of geospatial data.
Functionality
QGIS functions as geographic information system (GIS) ...
(GPL)
* SAGA GIS (GPL)
* TerraLib (LGPL)
* TerraView TerraView is a GIS application built on the TerraLib GIS library. TerraView handles vector data (polygons, lines, points) and raster data (grids and images), both of them stored in a relational or geo-relational database, including ACCESS, PostgreS ...
(GPL)
* uDig (LGPL)
See also
* Well-known text
Well-known text (WKT) is a text markup language for representing vector geometry objects. A binary equivalent, known as well-known binary (WKB), is used to transfer and store the same information in a more compact form convenient for computer pr ...
and binary, descriptions of geospatial objects used within PostGIS
* DE-9IM, the Dimensionally Extended nine-Intersection Model used by PostGIS
References
External links
*
{{DEFAULTSORT:Postgis
Free GIS software
PostgreSQL
Spatial database management systems