Referencing
===========

Used to interpret referencing information allowing the determination of a location given a set of
coordinates. Includes implementation of ``CoordinateReferenceSystem`` (CRS), conversion and
transformation services.

.. figure:: /images/gt-referencing.svg
   
   gt-referencing module

The gt-referencing module is our first example that makes use of the plugin system provided
by :doc:`gt-metadata <../metadata/index>`. It does require a little bit of care when configuring
the module with appropriate EPSG authority.

The ``gt-referencing`` module is responsible for:

* Implementation of the referencing interfaces from :doc:`gt-api <../api/index>` such
  as ``CoordinateReferenceSystem`` and ``MathTransform``
* Providing a definition for common spatial reference system codes using plugins available
  on the CLASSPATH

This module is basically care and feeding for the ``CoordinateReferenceSystem`` class - and enough
math to make it useful. Before you get too worried it is easy to use (There is a class called
CRS that has helper methods for reprojection and stuff).

References
''''''''''

* http://www.epsg-registry.org/

Maven
'''''

.. code-block:: xml

    <dependency>
      <groupId>org.geotools</groupId>
      <artifactId>gt-referencing</artifactId>
      <version>${geotools.version}</version>
    </dependency>
    <dependency>
      <groupId>org.geotools</groupId>
      <artifactId>gt-epsg-hsql</artifactId>
      <version>${geotools.version}</version>
    </dependency>
    <dependency>
      <groupId>org.geotools</groupId>
      <artifactId>gt-epsg-extension</artifactId>
      <version>${geotools.version}</version>
    </dependency>
    
Contents
--------

.. sidebar:: Details
   
   .. toctree::
      :maxdepth: 1
      
      faq
      internal

.. toctree::
   :maxdepth: 1
   
   crs
   axis
   order
   compare
   epsg
   parameter
   transform
   calculator

EPSG core providers (choose only one to prevent conflict):

.. toctree::
   :maxdepth: 1
   
   hsql
   postgresql
   wkt


Plugins:

.. toctree::
   :maxdepth: 1
   
   extension
   iau