Check if a point is in a MultiPolygonField

Using Django Forms & APIs
1

Hello agian :slight_smile:
I’ve created a simple model called ProvincialBorders where I’ve imported the GEOJSON file from this link: GeoJSON for South African provincial boundaries · GitHub
That gives me the borderes of all the provinces in South Africa and it works as I expected.

class ProvincialBorders(models.Model):
province = models.CharField(max_length=100)
geom = models.MultiPolygonField()

I have another model where I have single PointField.

class Bird(models.Model):
name = models.CharField(max_length=100)
location = models.PointField()

How can I check if the value of the Point is inside of the MultiPolygonField? If you can point me in the right direction it would be very much appriciated. Thanks

2

In the past I have used PyGEOS for this, but now it appears that the Shapely library would be the current tool-of-choice.

Also see:

3

I don’t think we need yet another lib to achieve that. The GeoDjango queryset API offers plenty of operators to check various geographic relationships between model fields (GIS QuerySet API Reference | Django documentation | Django).

e.g. all birds in a specific province: Bird.objects.filter(location__within=province.geom)
the province containing a bird: province.objects.get(geom__contains=bird.location)
etc.

2 Likes
4

Wow that is perfect, thank you so much