Dynamic Map Web Forms

How to use Python, GeoDjango, and OpenLayers to Create a Form that you can use to modify Geographic Features
Added by Gregory Roby 167 days ago

Recently a draw polygon feature was added to COOPGIS. To do so elegantly required using a form that a user could click on to create the points of the polygon. The below are some snippets that should help explain how to do so.

Simplified Django Model, with GeoModelAdmin.

@class StakerQuickGeneratePolygon(models.Model):
Polygon=models.PolygonField(db_column='the_geom', verbose_name=('polygon'), srid=djangoproject.settings.COOPGISSRID, null=True, blank=True)
objects=models.GeoManager()
class Meta:
app_label='djangoproject'
class StakerQuickGeneratePolygonAdmin(admin.GeoModelAdmin):
list_filter=('polygon',)
list_display=('object', 'polygon')@

Build a dynamic form using the Django dynamic form snippet. Code to setup the widget and build the form included:

geoAdmin=StakerQuickGeneratePolygonAdmin(StakerQuickGeneratePolygon, admin.site)

PolygonFormField=StakerQuickGeneratePolygon._meta.get_field('Polygon')

PolygonWidget=geoAdmin.get_map_widget(PolygonFormField)

Dict['Polygon']=forms.CharField(widget=PolygonWidget())

To process the form I used the line:

 polygon=fromstr(form.data['Polygon'])

From there, it was just using Django Python code to update the polygon, get a list of features within it, and otherwise return information to the user.

This polygon feature is used to more quickly make additions to a Staker Work Order in a defined area and should be available in the version of COOPGIS planned to be released around the end of the year.


Comments