How to filter a django model with latitude and longitude coordinates that fall within a certain radius

Question

I have the following model.

class Location(models.Model):
    name = models.CharField(max_length = 128, blank = True)
    address =models.CharField(max_length =          


        

Answer 1

If you don't want to use GeoDjango, then you could consider writing it out with Django's Database functions. In contrast to raw SQL, this also gives you the advantage of being able to easily append/prepend other ORM filters.

from django.db.models.functions import Radians, Power, Sin, Cos, ATan2, Sqrt, Radians
from django.db.models import F

dlat = Radians(F('latitude') - current_lat)
dlong = Radians(F('longitude') - current_long)

a = (Power(Sin(dlat/2), 2) + Cos(Radians(current_lat)) 
    * Cos(Radians(F('latitude'))) * Power(Sin(dlong/2), 2)
)

c = 2 * ATan2(Sqrt(a), Sqrt(1-a))
d = 6371 * c

LocationsNearMe = Location.objects.annotate(distance=d).order_by('distance').filter(distance__lt=10)