What is PostGIS

PostGIS is an extension to the ​PostgreSQL object-relational database system that allows ​GIS (Geographic Information System) objects to be stored in the database. PostGIS does for PostgreSQL what Oracle Spatial does for Oracle, ArcSDE does for Microsoft SQL Server/Oracle.

Overview

• Features of PostGIS
• ​PostGIS as a part of PostgreSQL (Article)]
• Tools that support PostGIS
• Gallery Collection of applications using PostGIS in the backend.
• PostgreSQL Case Studies
• PostGIS Hosters
• ​PostGIS Wikipedia entry
• PostGIS and ArcSDE/ArcGIS 9.3 Articles

Installation Guides

• Directions for PostGIS RPM Installation.
• Directions for PostGIS on Ubuntu.

Examples of Spatial SQL

• Find Nearby Features
• Find Features far from nearest neighbor - Anti-Near Neighbor
• Join Spatial and Non-Spatial Tables
• Overlay Geometries in one table with Geometries in another
• Find Features Inside a Particular Polygon
• Clean Invalid Polygon Topology
  • Find points on interior rings within a certain distance to exterior ring
• Splitting a Polygon with a Linestring
• Generating a hexagonal grid
• MultiPoint centroids from Multi geometries
• Examples OGR Examples

Extending PostGIS

• PostGIS EJB3 Integration
• Postgis Topology - to be moved somewhere else ;)
• Raster support
  • WKT Raster - The new proposed raster implementation in PostGIS
  • ​PGCHIP - The GDAL Postgis driver for raster data - a corrected version can be found in current GDAL CVS
• WishList of features for the future
• Code Sprint 2009 Notes

Newbie Common Problems and Questions

• addgeometrycolumn("unknown", "unknown", integer, "unknown", integer) does not exist function addgeometrycolumn("unknown", "unknown", integer, "unknown", integer) does not exist
• is the measurement returned by ST_Distance? What is the measurement returned by ST_Distance?
• What unit of measurement do PostGIS functions use?
• How to get distance measurement in meters

Extras

• Geocoder TigerGeocoder

Notes

• SpatialAlgorithmWebSites

Useful Additional PL/PGSQL Functions

• PL/PGSQL Functions
• Neighbor Search Nearest Neighbor Search
• PL/PGSQL Pseudo Cascade Union Aggregate Function

Known issues/patches pending review

• IssuesPatchesPending

What is GEOS

​GEOS is a C++ port of the JTS Topology Suite. It is used by PostGIS to implement Topological functions.