.. Basics
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.. _Basics:

Basics
======

.. contents:: Table of Contents
    :depth: 3
    :backlinks: top

This is a short description of the basic elements of the EOxServer software
architecture.

Architectural Layout
--------------------

EOxServer is Python software that builds on a handful of external packages.
Most of the description in the following sections is related to the structure
of the Python code, but in this section we present the building blocks used
for EOxServer.

For further information on the dependencies please refer to the
:doc:`/users/install` document in the :doc:`/users/index`.

Django
~~~~~~

EOxServer is designed as a series of Django apps. It reuses the 
object-relational mapping Django provides as an abstraction layer for database 
access. Therefore, it is not bound to a specific database application, but can
be run with different backends.

Database
~~~~~~~~

Metadata and part of the EOxServer configuration is stored in a database. A
handful of geospatially enabled database systems is supported, though we
recommend either PostGIS or SpatiaLite.

MapServer
~~~~~~~~~

Many built-in functionalities rely on `MapServer <http://www.mapserver.org>`_
which EOxServer uses through its Python bindings to handle certain OGC Web
Service requests.

GDAL/OGR
~~~~~~~~

In some cases EOxServer uses the `GDAL/OGR <http://www.gdal.org>`_ library for
access to geospatial data directly (rather than through MapServer).