I have the following code.


class PFT(models.Model):

    geom = models.PointField(srid=4326)
    def __str__(self):              
        return '%s %s %s' % (self.species, self.geom.x, self.geom.y)


def geojson_provinces(request):
    conn = psycopg2.connect(dbname="geodjango",host='localhost',user='postgres', password='postgres', port=5433)
    dict_cur = conn.cursor(cursor_factory=psycopg2.extras.DictCursor)
    res = dict_cur.execute("SELECT ST_AsGeoJson(geom) AS json FROM pft_pft LIMIT 10;")


    json_res  = []
    for row in points:
        json_obj  = row['json']
    #json = simplejson.dumps(data)
    return render_to_response('map.html',
                          {'json_res': json_res},


url(r'^geojson/$', geojson_provinces, name='geojson_provinces'),

Javascript code in map.html


    var map = new ol.Map({
       layers: [
          new ol.layer.Tile({
             source: new ol.source.OSM()
       , target: 'map'
       , view: new ol.View({
          center: [0, 0]
          , zoom: 2

    var vectorSourceJsonp = new ol.source.Vector({
       format: new ol.format.GeoJSON()
       , loader: function(extent, resolution, projection) {        
             url: "{% url 'geojson_provinces' %}"
             , dataType: 'jsonp'
       , strategy: ol.loadingstrategy.createTile(new ol.tilegrid.XYZ({
          maxZoom: 19
       , projection: 'EPSG:4326'
    // Executed when data is loaded by the $.ajax method.
    var loadFeatures = function(response) {
    // Vector layer
    var vectorLayerJsonp = new ol.layer.Vector({
       source: vectorSourceJsonp
       , style: new ol.style.Style({
          stroke: new ol.style.Stroke({
             color: 'green'
             , width: 2
    var mapJsonp = new ol.Map({
       target: 'mapJsonp'
       , renderer: 'canvas'
       , layers: [osmLayer, vectorLayerJsonp]
       , view: new ol.View({
          center: [-75.923853, 45.428736]
          , maxZoom: 19
          , zoom: 11


When I run http://localhost:8000/geojson only map is getting displayed but not the GeoJSON data as points.

  • Can you post your geojson? – Stefan Jan 7 '16 at 12:04
  • my geojson data is ["{\"type\":\"Point\",\"coordinates\":[76.996944,31.58]}", "{\"type\":\"Point\",\"coordinates\":[76.670778,31.487083]}", "{\"type\":\"Point\",\"coordinates\":[77.253,30.651722]}", "{\"type\":\"Point\",\"coordinates\":[76.672944,31.48325]}", "{\"type\":\"Point\",\"coordinates\":[76.669306,31.456861]}", "{\"type\":\"Point\",\"coordinates\":[76.587101,31.451527]}", "{\"type\":\"Point\",\"coordinates\":[76.590461,31.598462]}", "{\"type\":\"Point\",\"coordinates\":[76.554306,31.607389]}", "{\"type\":\"Point\",\"coordinates\":.. – Bruce Jan 7 '16 at 12:08

Instead of running raw sql querries, you should use the geodjango api that does the work for you. There is a geojson serializer that does exaclty what you want, see the docs here.


from django.core.serializers import serialize
from myapp.models import PFT

def geojson_provinces(request):
    first10_serialized = serialize(
        fields=('species', ),
    return render_to_response(
        {'json_res': first10_serialized},

This create valid geojson in your view's response. I am not familiar with openlayers so can't tell if you also have some problems in your javascript.

  • When I use the above code I'm getting the following result where geometry is null {"type": "FeatureCollection", "crs": {"type": "name", "properties": {"name": "EP SG:4326"}}, "features": [{"type": "Feature", "geometry": null, properties": {"species": "Pinus roxburghii Sargent"}}, {"type": "Feature", "geometry": null, "properties": {"species": "Pinus roxburghii Sargent"}}, {"type": "Feature", "geometry": null, "properties": {"species": "Pinus roxburghii Sargent"}}, {"type": "Feature", "geometry": null, "properties": {"species": ... – Bruce Jan 7 '16 at 13:54
  • C:\Python34\lib\site-packages\django\shortcuts.py:45: RemovedInDjango110Warning: The context_instance argument of render_to_string is deprecated. using=using) – Bruce Jan 7 '16 at 13:57
  • I updated the answer, try removing the geometry_field argument. If you dont have data, it could mean that you have rows that don't have a geometry. Try also PFT.objects.filter(geom__isnull=False)[:10]. What does print [dat.geom for dat in PFT.objects.all()[:10]] return? – yellowcap Jan 7 '16 at 14:23
  • print [dat.geom for dat in PFT.objects.all()[:10]] returns <generator object <genexpr> at 0x04572530>. And my table has rows with geometry – Bruce Jan 7 '16 at 14:32
  • The print is not very useful like this, the goal was to see the geometries. Could you try for dat in PFT.objects.all()[:10]: print dat.geom? – yellowcap Jan 7 '16 at 14:56

I think you need to parse your GEOJSON string. You can do it with the following code:

var obj = JSON.parse(json);

The obj variable contains the parsed GEOJSON. You can check the validity of your data on http://geojsonlint.com/

Change the following code to parse the response:

var loadFeatures = function(response) {


var loadFeatures = function(response) {
  • Please could you let me know in which part of the code I must parse – Bruce Jan 7 '16 at 14:38
  • I changed accordingly but still data is not getting displayed. In the command line Im getting 'The context_instance argument of render_to_string is deprecated. using=using)' – Bruce Jan 7 '16 at 14:54
  • Have you tried the solution provided by @yellowcap? – Stefan Jan 7 '16 at 14:57
  • Yes. In that solution m getting geometry as null even though there is geometry in the table – Bruce Jan 7 '16 at 14:59
  • Unfortunately I cannot help you any further. Good luck – Stefan Jan 7 '16 at 15:00

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