Fixed small errors in GeoDjango tutorial, enhanced code pygmentation in install document.

GeoDjango Installation

======================

.. highlight:: console

Overview

========

In general, GeoDjango installation requires:

Can't find GEOS Library

~~~~~~~~~~~~~~~~~~~~~~~

When GeoDjango can't find GEOS, this error is raised::

When GeoDjango can't find GEOS, this error is raised:

.. code-block:: text

    ImportError: Could not find the GEOS library (tried "geos_c"). Try setting GEOS_LIBRARY_PATH in your settings.

If your GEOS library is in a non-standard location, or you don't want to

modify the system's library path then the :setting:`GEOS_LIBRARY_PATH`

setting may be added to your Django settings file with the full path to the

GEOS C library.  For example::

GEOS C library.  For example:

.. code-block:: python

    GEOS_LIBRARY_PATH = '/home/bob/local/lib/libgeos_c.so'

~~~~~~~~~~~~~~~~~~~~~~~

When GeoDjango can't find the GDAL library, the ``HAS_GDAL`` flag

will be false::

will be false:

.. code-block:: pycon

    >>> from django.contrib.gis import gdal

    >>> gdal.HAS_GDAL

If your GDAL library is in a non-standard location, or you don't want to

modify the system's library path then the :setting:`GDAL_LIBRARY_PATH`

setting may be added to your Django settings file with the full path to

the GDAL library.  For example::

the GDAL library.  For example:

.. code-block:: python

    GDAL_LIBRARY_PATH = '/home/sue/local/lib/libgdal.so'

When installed from source, GDAL versions 1.5.1 and below have an autoconf bug

that places data in the wrong location. [#]_   This can lead to error messages

like this::

like this:

.. code-block:: text

    ERROR 4: Unable to open EPSG support file gcs.csv.

    ...

    $ python manage.py shell

If using Apache, you may need to add this environment variable to your configuration

file::

file:

.. code-block:: apache

    SetEnv GDAL_DATA /usr/local/share

    $ cd pysqlite-2.6.0

Next, use a text editor (e.g., ``emacs`` or ``vi``) to edit the ``setup.cfg`` file

to look like the following::

to look like the following:

.. code-block:: ini

    [build_ext]

    #define=

projection (a spherical mercator projection used by Google Maps),

an entry must be added to your spatial database's ``spatial_ref_sys`` table.

Invoke the Django shell from your project and execute the

``add_srs_entry`` function::

``add_srs_entry`` function:

.. code-block:: pycon

    $ python manage shell

    >>> from django.contrib.gis.utils import add_srs_entry

    Use of these binaries requires Django 1.0.3 and above.  If you are

    using a previous version of Django (like 1.0.2), then you will have

    to add the following in your settings::

    to add the following in your settings:

    .. code-block:: python

        GEOS_LIBRARY_PATH='/Library/Frameworks/GEOS.framework/GEOS'

        GDAL_LIBRARY_PATH='/Library/Frameworks/GDAL.framework/GDAL'

~~~~~~~~~

Follow the :ref:`pysqlite2` source install instructions, however,

when editing the ``setup.cfg`` use the following instead::

when editing the ``setup.cfg`` use the following instead:

.. code-block:: ini

    [build_ext]

    #define=

    $ sudo cp spatialite /Library/Frameworks/SQLite3.framework/Programs

Finally, for GeoDjango to be able to find the KyngChaos SpatiaLite library,

add the following to your ``settings.py``::

add the following to your ``settings.py``:

.. code-block:: python

    SPATIALITE_LIBRARY_PATH='/Library/Frameworks/SQLite3.framework/SQLite3'

In order to use GeoDjango, you will need to add your Python and OSGeo4W

directories to your Windows system ``Path``, as well as create ``GDAL_DATA``

and ``PROJ_LIB`` environment variables.  The following set of commands,

executable with ``cmd.exe``, will set this up::

executable with ``cmd.exe``, will set this up:

.. code-block:: bat

     set OSGEO4W_ROOT=C:\OSGeo4W

     set PYTHON_ROOT=C:\Python27

.. code-block:: sql

    BEGIN;

    CREATE TABLE "world_worldborders" (

    CREATE TABLE "world_worldborder" (

        "id" serial NOT NULL PRIMARY KEY,

        "name" varchar(50) NOT NULL,

        "area" integer NOT NULL,

        "lat" double precision NOT NULL

    )

    ;

    SELECT AddGeometryColumn('world_worldborders', 'mpoly', 4326, 'MULTIPOLYGON', 2);

    ALTER TABLE "world_worldborders" ALTER "mpoly" SET NOT NULL;

    CREATE INDEX "world_worldborders_mpoly_id" ON "world_worldborders" USING GIST ( "mpoly" GIST_GEOMETRY_OPS );

    SELECT AddGeometryColumn('world_worldborder', 'mpoly', 4326, 'MULTIPOLYGON', 2);

    ALTER TABLE "world_worldborder" ALTER "mpoly" SET NOT NULL;

    CREATE INDEX "world_worldborder_mpoly_id" ON "world_worldborder" USING GIST ( "mpoly" GIST_GEOMETRY_OPS );

    COMMIT;

If satisfied, you may then create this table in the database by running the

``syncdb`` management command::

    $ python manage.py syncdb

    Creating table world_worldborders

    Creating table world_worldborder

    Installing custom SQL for world.WorldBorder model

The ``syncdb`` command may also prompt you to create an admin user; go ahead

.. code-block:: bash

    $ python manage.py ogrinspect world/data/TM_WORLD_BORDERS-0.3.shp WorldBorder --srid=4326 --mapping --multi

    $ python manage.py ogrinspect world/data/TM_WORLD_BORDERS-0.3.shp WorldBorder \

        --srid=4326 --mapping --multi

A few notes about the command-line options given above:

    >>> qs = WorldBorder.objects.filter(mpoly__intersects=pnt)

    >>> print qs.query # Generating the SQL

    SELECT "world_worldborders"."id", "world_worldborders"."name", "world_worldborders"."area",

    "world_worldborders"."pop2005", "world_worldborders"."fips", "world_worldborders"."iso2",

    "world_worldborders"."iso3", "world_worldborders"."un", "world_worldborders"."region",

    "world_worldborders"."subregion", "world_worldborders"."lon", "world_worldborders"."lat",

    "world_worldborders"."mpoly" FROM "world_worldborders"

    WHERE ST_Intersects("world_worldborders"."mpoly", ST_Transform(%s, 4326))

    SELECT "world_worldborder"."id", "world_worldborder"."name", "world_worldborder"."area",

    "world_worldborder"."pop2005", "world_worldborder"."fips", "world_worldborder"."iso2",

    "world_worldborder"."iso3", "world_worldborder"."un", "world_worldborder"."region",

    "world_worldborder"."subregion", "world_worldborder"."lon", "world_worldborder"."lat",

    "world_worldborder"."mpoly" FROM "world_worldborder"

    WHERE ST_Intersects("world_worldborder"."mpoly", ST_Transform(%s, 4326))

    >>> qs # printing evaluates the queryset

    [<WorldBorder: United States>]