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 Metacarta.
In addition to the regular form field arguments, GeoDjango form fields take the following optional arguments.
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.
GeoDjango widgets are template-based, so their attributes are mostly different from other Django widget attributes.
The OpenGIS geometry type, generally set by the form field.
Height and width of the widget map (default is 400x600).
SRID code used by the map (default is 4326).
Boolean value specifying if a textarea input showing the serialized representation of the current geometry is visible, mainly for debugging purposes (default is False).
Indicates if the widget supports edition of 3D data (default is False).
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}))
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 template_name class attribute.
OpenLayersWidget
This is the default widget used by all GeoDjango form fields. template_name is gis/openlayers.html.
OpenLayersWidget and OSMWidget use the openlayers.js file hosted on the openlayers.org Web site. This works for basic usage during development, but isn’t appropropriate for a production deployment as openlayers.org/api/ has no guaranteed uptime and runs on a slow server. You are therefore advised to subclass these widgets in order to specify your own version of the openlayers.js file in the js property of the inner Media class (see Assets as a static definition). You can host a copy of openlayers.js tailored to your needs on your own server or refer to a copy from a content-delivery network like http://cdnjs.com/. This will also allow you to serve the JavaScript file(s) using the https protocol if needed.
OSMWidget
This widget uses an OpenStreetMap base layer (Mapnik) to display geographic objects on. template_name is gis/openlayers-osm.html.
The OpenLayersWidget note about JavaScript file hosting above also applies here. See also this FAQ answer about https access to map tiles.
Jul 20, 2015