Re: Best way to find near people

On Jul 29, 2010, at 2:58 PM, Alexandre González wrote:

> Hi!
>
> I'm searching near people in my app. I'm doing it a this way:
>
> 37 people = Person.objects.all().exclude(user=request.user)
> 38
> 39 near_people = list()
> 40 for person in people:
> 41 if self.is_near(me.coordinates, person.coordinates): near_people.append(person)
>
> Now, I'm getting all the the Person objects. This is a inefficient way.
>
> The coordinates are latitude/longitude coordinates, so I think in test the variation and get only latitude +/- 1 and longitude +/- 1 and after this, do the test exactly (the funcion is_near).
>
> But instead this, can I "draw" a circle and search only Person objects inside it?

I'm not sure what database you are using, but if you are using PostgreSQL, it has built-in geometric operators specifically for this kind of thing. You might have to drop down into SQL, but in 1.2, that's nice and easy.

The PostgreSQL documentation on this is at:

http://www.postgresql.org/docs/8.4/interactive/datatype-geometric.html
--
-- Christophe Pettus
xof@thebuild.com

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