CODEWITHSUNDEEP
pythondjangotastypiegeodjango
Twitch
Twitch

Reputation: 693

How can I measure distance with tastypie and geodjango?

Using Tastypie and GeoDjango, I'm trying to return results of buildings located within 1 mile of a point.

The TastyPie documentation states that distance lookups are not yet supported, but I am finding examples of people getting it work, such as this discussion and this discussion on StackOverflow, but no working code examples that can be applied.

The idea that I am trying to work with is if I append a GET command to the end of a URL, then nearby locations are returned, for example: 

http://website.com/api/?format=json&building_point__distance_lte=[{"type": "Point", "coordinates": [153.09537, -27.52618]},{"type": "D", "m" : 1}]

But when I try that, all I get back is: 

{"error": "Invalid resource lookup data provided (mismatched type)."}

I've been pouring over the Tastypie document for days now and just can't figure out how to implement this.

I'd provide more examples, but I know they'd be all terrible. All advice is appreciated, thank you!

Upvotes: 3

Views: 187

Answers (1)

Twitch
Twitch

Reputation: 693

Got it working, here is an example for posterity:

In the api.py, create a Resource that looks like this: 

from django.contrib.gis.geos import *

class LocationResource(ModelResource):
    class Meta:
        queryset = Building.objects.all()
        resource_name = 'location'

    def apply_sorting(self, objects, options=None):
        if options and "longitude" in options and "latitude" in options:
            pnt = fromstr("POINT(" + options['latitude'] + " " + options['longitude'] + ")", srid=4326)
            return objects.filter(building_point__distance_lte=(pnt, 500))

        return super(LocationResource, self).apply_sorting(objects, options)

The "building" field is defined as a PointField in models.py.

Then in the URL for the resource, append the following, for example: 

&latitude=-88.1905699999999939&longitude=40.0913469999999990

This will return all objects within 500 meters.

Upvotes: 2

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