PostGIS

PostGIS adds support for geographic objects to the PostgreSQL object-relational database. In effect, PostGIS "spatially enables" the PostgreSQL server, allowing it to be used as a backend spatial database for geographic information systems (GIS), much like ESRI's SDE or Oracle's Spatial extension. PostGIS follows the OpenGIS "Simple Features Specification for SQL" and has been certified as compliant with the "Types and Functions" profile.

Install

When you install PostgreSQL, do not install the PostGIS included in the PostgreSQL installer, it is often a few versions behind.Instead, use the separate PostGIS installer.

Linux & UNIX

tar xvfz postgis-1.3.1.tar.gz
cd postgis-1.3.1
./configure
make
make install
createlang plpgsql yourtestdatabase
psql -d yourtestdatabase -f lwpostgis.sql
psql -d yourtestdatabase -f spatial_ref_sys.sql

or Windows

http://postgis.refractions.net/download/windows/
psql -U postgres postgis
postgis=# SELECT postgis_version();

DB initialization

• createlang plpgsql yourdatabase
• psql -f lwpostgis.sql -d yourdatabase
• psql -f spatial_ref_sys.sql -d yourdatabase

sql in \PostgreSQL\8.3\share\contrib

two OpenGIS meta-data tables: SPATIAL_REF_SYS and GEOMETRY_COLUMNS.

CREATE TABLE spatial_ref_sys
(
  srid integer NOT NULL,
  auth_name character varying(256),
  auth_srid integer,
  srtext character varying(2048),
  proj4text character varying(2048),
  CONSTRAINT spatial_ref_sys_pkey PRIMARY KEY (srid)
)

CREATE TABLE geometry_columns ( 
  f_table_catalog    VARRCHAR(256) NOT NULL, 
  f_table_schema     VARCHAR(256) NOT NULL,
  f_table_nam        VARCHAR(256) NOT NULL, 
  f_geometry_column  VARCHAR(256) NOT NULL, 
  coord_dimension    INTEGER NOT NULL, 
  srid               INTEGER NOT NULL, 
  type               VARCHAR(30) NOT NULL 
)

template_postgis

template_postgis template database include PostGIS functions

create spatially-enabled databases

createdb -T template_postgis my_spatial_db
or
CREATE DATABASE my_spatial_db TEMPLATE=template_postgis 

Links

• http://postgis.refractions.net