.. _download_osm:

Download OSM data
###################################

Download OpenStreetMap data
*****************************************************

You can use the following two methods to download the OpenStreetMap
data:

1. `OpenStreetMapOfficial <https://www.openstreetmap.org/>`_:
choose ``Export`` -> ``OverpassAPI``
(otherwise the size of the bounding box size is limited).

.. image:: ../_static/map_related/osm_official.png
    :width: 100%
    :align: center
    :alt: OpenStreetMap Official

By this way, you will get the *complete* OSM data (xml),
then you can use ``osm_filter.osm_way_filter()`` to get
the layer you need.

2. `Overpass API <http://overpass-turbo.eu/>`_ (recommended):
directly use overpass API to download the layer you need.
The sample query code is attached in the appendix :ref:`query_code`.

.. image:: ../_static/map_related/overpass.png
    :width: 100%
    :align: center
    :alt: Overpass API

In this way, you will directly get the layer you need.


Parse OpenStreetMap data
*****************************************************

The downloaded OpenStreetMap xml file can be parsed using
the :func:`mtldp.mtlmap.build_network_from_xml`:

.. code-block:: python
    :linenos:

    import mtldp.mtlmap as mtlmap
    network = mtlmap.build_network_from_xml("*.osm")

This will return you a well-structured class
:class:`mtldp.mtlmap.Network`.

.. _query_code:

Appendix A: Query code
************************************************

Here is an example of the query code using the OverpassAPI.

.. literalinclude:: ../_static/overpass.xml
    :linenos:

.. _OpenStreetMapOfficial <https://www.openstreetmap.org/>: