===================
GeoDjango Forms API
===================
.. module:: django.contrib.gis.forms
:synopsis: GeoDjango forms API.
GeoDjango provides some specialized form fields and widgets in order to visually
display and edit geolocalized data on a map. By default, they use
`OpenLayers`_-powered maps, with a base WMS layer provided by `NASA`_.
.. _OpenLayers: http://openlayers.org/
.. _NASA: https://earthdata.nasa.gov/
Field arguments
===============
In addition to the regular :ref:`form field arguments <core-field-arguments>`,
GeoDjango form fields take the following optional arguments.
``srid``
--------
.. attribute:: Field.srid
This is the SRID code that the field value should be transformed to. For
example, if the map widget SRID is different from the SRID more generally
used by your application or database, the field will automatically convert
input values into that SRID.
``geom_type``
-------------
.. attribute:: Field.geom_type
You generally shouldn't have to set or change that attribute which should
be setup depending on the field class. It matches the OpenGIS standard
geometry name.
Form field classes
==================
``GeometryField``
-----------------
.. class:: GeometryField
``PointField``
--------------
.. class:: PointField
``LineStringField``
-------------------
.. class:: LineStringField
``PolygonField``
----------------
.. class:: PolygonField
``MultiPointField``
-------------------
.. class:: MultiPointField
``MultiLineStringField``
------------------------
.. class:: MultiLineStringField
``MultiPolygonField``
---------------------
.. class:: MultiPolygonField
``GeometryCollectionField``
---------------------------
.. class:: GeometryCollectionField
Form widgets
============
.. module:: django.contrib.gis.forms.widgets
:synopsis: GeoDjango widgets API.
GeoDjango form widgets allow you to display and edit geographic data on a
visual map.
Note that none of the currently available widgets supports 3D geometries, hence
geometry fields will fallback using a simple ``Textarea`` widget for such data.
Widget attributes
-----------------
GeoDjango widgets are template-based, so their attributes are mostly different
from other Django widget attributes.
.. attribute:: BaseGeometryWidget.geom_type
The OpenGIS geometry type, generally set by the form field.
.. attribute:: BaseGeometryWidget.map_height
.. attribute:: BaseGeometryWidget.map_width
Height and width of the widget map (default is 400x600).
.. attribute:: BaseGeometryWidget.map_srid
SRID code used by the map (default is 4326).
.. attribute:: BaseGeometryWidget.display_raw
Boolean value specifying if a textarea input showing the serialized
representation of the current geometry is visible, mainly for debugging
purposes (default is ``False``).
.. attribute:: BaseGeometryWidget.supports_3d
Indicates if the widget supports edition of 3D data (default is ``False``).
.. attribute:: BaseGeometryWidget.template_name
The template used to render the map widget.
You can pass widget attributes in the same manner that for any other Django
widget. For example::
from django.contrib.gis import forms
class MyGeoForm(forms.Form):
point = forms.PointField(widget=
forms.OSMWidget(attrs={'map_width': 800, 'map_height': 500}))
Widget classes
--------------
``BaseGeometryWidget``
.. class:: BaseGeometryWidget
This is an abstract base widget containing the logic needed by subclasses.
You cannot directly use this widget for a geometry field.
Note that the rendering of GeoDjango widgets is based on a template,
identified by the :attr:`template_name` class attribute.
``OpenLayersWidget``
.. class:: OpenLayersWidget
This is the default widget used by all GeoDjango form fields.
``template_name`` is ``gis/openlayers.html``.
``OpenLayersWidget`` and :class:`OSMWidget` use the ``openlayers.js`` file
hosted on the ``cdnjs.cloudflare.com`` content-delivery network. You can
subclass these widgets in order to specify your own version of the
``OpenLayers.js`` file `tailored to your needs`_ in the ``js`` property of
the inner ``Media`` class (see :ref:`assets-as-a-static-definition`).
.. versionchanged:: 1.11
Older versions use ``OpenLayers.js`` from ``openlayers.org`` which
isn't suitable for production use since it offers no guaranteed uptime
and runs on a slow server.
Also, the widget nows uses OpenLayers 3 instead of OpenLayers 2.
.. _tailored to your needs: http://openlayers.org/en/latest/doc/tutorials/custom-builds.html
``OSMWidget``
.. class:: OSMWidget
This widget uses an OpenStreetMap base layer to display geographic objects
on. Attributes are:
.. attribute:: template_name
``gis/openlayers-osm.html``
.. attribute:: default_lat
.. attribute:: default_lon
The default center latitude and longitude are ``47`` and ``5``,
respectively, which is a location in eastern France.
The :class:`OpenLayersWidget` note about JavaScript file hosting above also
applies here. See also this `FAQ answer`_ about ``https`` access to map
tiles.
.. versionchanged:: 1.11
OpenLayers 2.x has been dropped in favor of OpenLayers 3. If you extend
the ``gis/openlayers-osm.html`` template, please review your custom
template.
.. _FAQ answer: https://help.openstreetmap.org/questions/10920/how-to-embed-a-map-in-my-https-site
