- Author:
- simonw
- Posted:
- March 24, 2021
- Language:
- Python
- Version:
- 3.0
- Tags:
- orm gis latitude longitude location
- Score:
- 1 (after 1 ratings)

Here's how to find the 10 closest locations to a point for a model that has latitude and longitude columns, if you're not using GeoDjango.

This runs a brute force distance calculation against every row, so it should only be used on smaller tables - probably less than 100,000 rows.

For larger tables you should use GeoDjango instead.

See also my TIL about this.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | ```
from django.db.models import F
from django.db.models.functions import ACos, Cos, Radians, Sin
locations = Location.objects.annotate(
distance_miles = ACos(
Cos(
Radians(input_latitude)
) * Cos(
Radians(F('latitude'))
) * Cos(
Radians(F('longitude')) - Radians(input_longitude)
) + Sin(
Radians(input_latitude)
) * Sin(Radians(F('latitude')))
) * 3959
).order_by('distance_miles')[:10]
``` |

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