django-geojson is a set of tools to manipulate GeoJSON with Django :

• (De)Serializer for (Geo)Django objects, querysets and lists
• Base views to serve GeoJSON map layers from models
• GeoJSON model and form fields to avoid spatial database backends (compatible with django-leaflet for map widgets)

pip install django-geojson

This package has optional extra dependencies.

If you need GeoJSON fields with map widgets :

pip install "django-geojson [field]"

Add djgeojson to your applications :

# settings.py

INSTALLED_APPS += (
    'djgeojson',
)

(not required for views)

Very useful for web mapping :

# urls.py
from djgeojson.views import GeoJSONLayerView
...
url(r'^data.geojson$', GeoJSONLayerView.as_view(model=MushroomSpot), name='data'),

Consume the vector layer as usual, for example, with Leaflet loaded with jQuery Ajax:

# Leaflet JS
var layer = L.geoJson();
map.addLayer(layer);
$.getJSON("{% url 'data' %}", function (data) {
    layer.addData(data);
});

Inherit generic views only if you need a reusable set of options :

# views.py
from djgeojson.views import GeoJSONLayerView

class MapLayer(GeoJSONLayerView):
    # Options
    precision = 4   # float
    simplify = 0.5  # generalization


# urls.py
from .views import MapLayer, MeetingLayer
...
url(r'^mushrooms.geojson$', MapLayer.as_view(model=MushroomSpot, properties=('name',)), name='mushrooms')

Most common use-cases of reusable options are: low-fi precision, common list of fields between several views, etc.

Options are :

• properties : list of properties names, or dict for mapping field names and properties
• simplify : generalization of geometries (See simplify())
• precision : number of digit after comma
• geometry_field : name of geometry field (default: geom)
• srid : projection (default: 4326, for WGS84)
• bbox : Allows you to set your own bounding box on feature collection level
• bbox_auto : True/False (default false). Will automatically generate a bounding box on a per feature level.

Vectorial tiles can help display a great number of objects on the map, with reasonnable performance.

# urls.py
from djgeojson.views import TiledGeoJSONLayerView
...

url(r'^data/(?P<z>\d+)/(?P<x>\d+)/(?P<y>\d+).geojson$',
    TiledGeoJSONLayerView.as_view(model=MushroomSpot), name='data'),

Consume the vector tiles using Leaflet TileLayer GeoJSON, Polymaps, OpenLayers 3 or d3.js for example.

Options are :

• trim_to_boundary : if True geometries are trimmed to the tile boundary
• simplifications : a dict of simplification values by zoom level

Mainly useful to dump features in HTML output and bypass AJAX call :

// Leaflet JS
L.geoJson({{ object_list|geojsonfeature|safe}}).addTo(map);

Will work either for a model, a geometry field or a queryset.

{% load geojson_tags %}

var feature = {{ object|geojsonfeature|safe }};

var geom = {{ object.geom|geojsonfeature|safe }};

var collection = {{ object_list|geojsonfeature|safe }};

Properties and custom geometry field name can be provided.

{{ object|geojsonfeature:"name,age" }}
{{ object|geojsonfeature:"name,age:the_geom" }}
{{ object|geojsonfeature:":geofield" }}

GeoJSON fields are based on Brad Jasper's JSONField. See INSTALL to install extra dependencies.

They are useful to avoid usual GIS stacks (GEOS, GDAL, PostGIS...) for very simple use-cases (no spatial operation yet).

from djgeojson.fields import PointField

class Address(models.Model):
    geom = PointField()

address = Address()
address.geom = {'type': 'Point', 'coordinates': [0, 0]}
address.save()

Form widgets are rendered with Leaflet maps automatically if django-leaflet is available.

All geometry types are supported and respectively validated : GeometryField, PointField, MultiPointField, LineStringField, MultiLineStringField, PolygonField, MultiPolygonField, GeometryCollectionField.

from djgeojson.serializers import Serializer as GeoJSONSerializer

GeoJSONSerializer().serialize(Restaurants.objects.all(), use_natural_keys=True, with_modelname=False)

from djgeojson.serializers import Serializer as GeoJSONSerializer

GeoJSONSerializer().deserialize('geojson', my_geojson)

You can optionally specify the model name directly in the parameters:

GeoJSONSerializer().deserialize('geojson', my_geojson, model_name=my_model_name)

Register the serializer in your project :

# settings.py

SERIALIZATION_MODULES = {
    'geojson' : 'djgeojson.serializers'
}

Command-line dumpdata can export files, viewable in GIS software like QGis :

python manage.py dumpdata --format=geojson yourapp.Model > export.geojson

Works with loaddata as well, which can now import GeoJSON files.

• Mathieu Leplatre <mathieu.leplatre@makina-corpus.com>
• Glen Robertson author of django-geojson-tiles at: https://github.com/glenrobertson/django-geojson-tiles/
• @jeffkistler's author of geojson serializer at: https://gist.github.com/967274
• Ben Welsh and Lukasz Dziedzia for quick test script
• Florent Lebreton http://github.com/fle

Version 1.X:

• Daniel Sokolowski, serializer snippet
• ozzmo, python 2.6 compatibility

_

• Lesser GNU Public License