PostGIS Extension for PostgreSQL
================================

PostgreSQL 9.1 (and up) supports PostGIS extensions. A database can easily be
extended to use PostGIS using the syntax::

  CREATE EXTENSION postgis;           -- Includes raster
  CREATE EXTENSION postgis_topology;  -- Depends on postgis

Requirements
------------
 * PostgreSQL 9.1 or later
 * PostGIS must be configured and built ``--with-raster``

Building and installing
-----------------------
First, make sure you follow the regular configuration and installation steps,
completing these steps::

  make
  make install

If you are building from the source SVN repository, it is also recommended to
make the comments, since the function descriptions will be included::

  make comments

Making the comments is not necessary if you are building from the tar.gz source
distributions, since these include pre-built ``postgis_comments.sql``,
``topology_comments.sql``, and ``raster_comments.sql`` files.

Then, to build and install the extensions::

  cd extensions
  make
  make install

The extensions are installed in `SHAREDIR/extension`. (If you're uncertain
where `SHAREDIR` is, run ``pg_config --sharedir``.)

Then in your PostgreSQL database run::

  CREATE EXTENSION postgis;
  CREATE EXTENSION postgis_topology;

The dependency logic should warn if you try to install ``postgis_topology``
without ``postgis`` or try to drop ``postgis`` without first dropping
``postgis_topology``.

You will also not be able to drop any PostGIS functions installed by the
extension.

Manual extension installation
-----------------------------
If you want to manually install the extensions from one server to another,
just copy over the following files to the `SHAREDIR/extension` directory:

 * PostGIS (including raster); from ``extensions/postgis``:
    ``postgis.control``
    ``sql/*``

 * Topology extension; from ``extensions/postgis_topolology``:
     ``postgis_topology.control``
     ``sql/*``
