= How to install PostGIS 2.0 on Ubuntu 12.04 LTS (''precise'') from source =

== Prerequisites ==
Several components are needed, which can either be built from source or installed from pre-built packages, as shown below.

Install prerequisite packages using:
{{{
sudo apt-get install build-essential postgresql-9.1 postgresql-server-dev-9.1 libxml2-dev libproj-dev libjson0-dev xsltproc docbook-xsl docbook-mathml
}}}

Optional package for raster support (this is required if you want to build the PostgreSQL extensions):
{{{
sudo apt-get install libgdal1-dev
}}}

=== Build GEOS 3.3.x ===
PostGIS 2.0 requires GEOS >= 3.3.2 for topology support, however Ubuntu 12.04 only has GEOS 3.2.2 available in packages, so it needs to be built from source. If you don't need topology, you don't ''need'' to build this component, but it is highly recommended.

There are multiple ways to build GEOS, but this is the simplest:
{{{
wget http://download.osgeo.org/geos/geos-3.3.7.tar.bz2
tar xvfj geos-3.3.7.tar.bz2
cd geos-3.3.7
./configure
make
sudo make install
cd ..
}}}

== Build PostGIS ==
{{{
wget http://download.osgeo.org/postgis/source/postgis-2.0.2.tar.gz
tar xfvz postgis-2.0.2.tar.gz
cd postgis-2.0.2
}}}

PostGIS 2.0 can be configured to disable topology or raster components, using the configure flags `--without-raster` and/or `--without-topology`. The default is to build both. Note that raster is required for the extension installation method for PostgreSQL.
{{{
./configure
make
sudo make install
sudo ldconfig
sudo make comments-install
}}}

Lastly, enable the command-line tools to work from your shell:
{{{
sudo ln -sf /usr/share/postgresql-common/pg_wrapper /usr/local/bin/shp2pgsql
sudo ln -sf /usr/share/postgresql-common/pg_wrapper /usr/local/bin/pgsql2shp
sudo ln -sf /usr/share/postgresql-common/pg_wrapper /usr/local/bin/raster2pgsql
}}}

== Spatially enabling a database ==
With PostgreSQL 9.1, there are two methods to add PostGIS functionality to a database: using extensions, or using enabler scripts.

=== PostGIS Extension for PostgreSQL ===
Spatially enabling a database using extensions is a new feature of PostgreSQL 9.1.

Connect to your database using pgAdmin or psql, and run the following commands. To add postgis with raster support:
{{{
CREATE EXTENSION postgis;
}}}

To add topology support, a second extension can be created on the database:
{{{
CREATE EXTENSION postgis_topology;
}}}

=== Enabler Scripts / Template ===

Enabler scripts can be used to either build a template, or directly spatially enable a database. This method is older than the extension method, but is required if the raster support is not built.

The following example creates a template, which can be re-used for creating multiple spatially-enabled databases. Or if you just want to make one spatially enabled database, you can modify the commands for your needs.

PostGIS:
{{{
sudo -u postgres createdb template_postgis
sudo -u postgres psql -d template_postgis -c "UPDATE pg_database SET datistemplate=true WHERE datname='template_postgis'"
sudo -u postgres psql -d template_postgis -f /usr/share/postgresql/9.1/contrib/postgis-2.0/postgis.sql
sudo -u postgres psql -d template_postgis -f /usr/share/postgresql/9.1/contrib/postgis-2.0/spatial_ref_sys.sql
sudo -u postgres psql -d template_postgis -f /usr/share/postgresql/9.1/contrib/postgis-2.0/postgis_comments.sql
}}}

with raster support:
{{{
sudo -u postgres psql -d template_postgis -f /usr/share/postgresql/9.1/contrib/postgis-2.0/rtpostgis.sql
sudo -u postgres psql -d template_postgis -f /usr/share/postgresql/9.1/contrib/postgis-2.0/raster_comments.sql
}}}

with topology support:
{{{
sudo -u postgres psql -d template_postgis -f /usr/share/postgresql/9.1/contrib/postgis-2.0/topology.sql
sudo -u postgres psql -d template_postgis -f /usr/share/postgresql/9.1/contrib/postgis-2.0/topology_comments.sql
}}}

== See also ==
 * https://help.ubuntu.com/community/PostgreSQL