Installing PostGIS

PostGIS adds geographic object support to PostgreSQL, turning it into a spatial database. GEOS, PROJ.4 and GDAL should be installed prior to building PostGIS. You might also need additional libraries, see PostGIS requirements.

Note

The psycopg2 module is required for use as the database adapter when using GeoDjango with PostGIS.

On Debian/Ubuntu, you are advised to install the following packages: postgresql-x.x, postgresql-x.x-postgis, postgresql-server-dev-x.x, python-psycopg2 (x.x matching the PostgreSQL version you want to install). Please also consult platform-specific instructions if you are on Mac OS X or Windows.

Building from source

First download the source archive, and extract:

$ wget http://download.osgeo.org/postgis/source/postgis-2.1.5.tar.gz
$ tar xzf postgis-2.1.5.tar.gz
$ cd postgis-2.1.5

Next, configure, make and install PostGIS:

$ ./configure

Finally, make and install:

$ make
$ sudo make install
$ cd ..

Note

GeoDjango does not automatically create a spatial database. Please consult the section on Creating a spatial database with PostGIS 2.0 and PostgreSQL 9.1+ or Creating a spatial database template for earlier versions for more information.

Post-installation

Creating a spatial database with PostGIS 2.0 and PostgreSQL 9.1+

PostGIS 2 includes an extension for Postgres 9.1+ that can be used to enable spatial functionality:

$ createdb  <db name>
$ psql <db name>
> CREATE EXTENSION postgis;

GeoDjango does not currently leverage any PostGIS topology functionality. If you plan to use those features at some point, you can also install the postgis_topology extension by issuing CREATE EXTENSION postgis_topology;.

Changed in Django 1.8:

The CREATE EXTENSION postgis command is now automatically run during the migrate process. You can still create it manually if you wish.

Creating a spatial database template for earlier versions

If you have an earlier version of PostGIS or PostgreSQL, the CREATE EXTENSION isn’t available and you need to create the spatial database using the following instructions.

Creating a spatial database with PostGIS is different than normal because additional SQL must be loaded to enable spatial functionality. Because of the steps in this process, it’s better to create a database template that can be reused later.

First, you need to be able to execute the commands as a privileged database user. For example, you can use the following to become the postgres user:

$ sudo su - postgres

Note

The location and name of the PostGIS SQL files (e.g., from POSTGIS_SQL_PATH below) depends on the version of PostGIS. Version 1.5 uses <sharedir>/contrib/postgis-1.5/postgis.sql.

To complicate matters, Debian/Ubuntu distributions have their own separate directory naming system that might change with time. In this case, use the create_template_postgis-debian.sh script.

The example below assumes PostGIS 1.5, thus you may need to modify POSTGIS_SQL_PATH and the name of the SQL file for the specific version of PostGIS you are using.

Once you’re a database super user, then you may execute the following commands to create a PostGIS spatial database template:

$ POSTGIS_SQL_PATH=`pg_config --sharedir`/contrib/postgis-2.0
# Creating the template spatial database.
$ createdb -E UTF8 template_postgis
$ createlang -d template_postgis plpgsql # Adding PLPGSQL language support.
# Allows non-superusers the ability to create from this template
$ psql -d postgres -c "UPDATE pg_database SET datistemplate='true' WHERE datname='template_postgis';"
# Loading the PostGIS SQL routines
$ psql -d template_postgis -f $POSTGIS_SQL_PATH/postgis.sql
$ psql -d template_postgis -f $POSTGIS_SQL_PATH/spatial_ref_sys.sql
# Enabling users to alter spatial tables.
$ psql -d template_postgis -c "GRANT ALL ON geometry_columns TO PUBLIC;"
$ psql -d template_postgis -c "GRANT ALL ON geography_columns TO PUBLIC;"
$ psql -d template_postgis -c "GRANT ALL ON spatial_ref_sys TO PUBLIC;"

These commands may be placed in a shell script for later use; for convenience the following scripts are available:

PostGIS version	Bash shell script
1.5	create_template_postgis-1.5.sh
Debian/Ubuntu	create_template_postgis-debian.sh

Afterwards, you may create a spatial database by simply specifying template_postgis as the template to use (via the -T option):

$ createdb -T template_postgis <db name>

Note

While the createdb command does not require database super-user privileges, it must be executed by a database user that has permissions to create databases. You can create such a user with the following command:

$ createuser --createdb <user>

PostgreSQL’s createdb fails

When the PostgreSQL cluster uses a non-UTF8 encoding, the create_template_postgis-*.sh script will fail when executing createdb:

createdb: database creation failed: ERROR:  new encoding (UTF8) is incompatible
  with the encoding of the template database (SQL_ASCII)

The current workaround is to re-create the cluster using UTF8 (back up any databases before dropping the cluster).

Managing the database

To administer the database, you can either use the pgAdmin III program (Start ‣ PostgreSQL 9.x ‣ pgAdmin III) or the SQL Shell (Start ‣ PostgreSQL 9.x ‣ SQL Shell). For example, to create a geodjango spatial database and user, the following may be executed from the SQL Shell as the postgres user:

postgres# CREATE USER geodjango PASSWORD 'my_passwd';
postgres# CREATE DATABASE geodjango OWNER geodjango TEMPLATE template_postgis ENCODING 'utf8';