[postgis-users] Nearest neighbor in 3D

[Paul Ramsey]

Using ST_3DDistance will work and give you the right answer, but it
will not be index assisted. The KNN operator <-> is only implemented
against the 2D index currently.

Paul

On Fri, May 25, 2012 at 5:15 PM, Bartosz Bekier
<bartosz.bekier at gmail.com> wrote:
> Hello All!
>
> This is my first post on the PostGIS mailing list:-).
>
> I would like to use the <-> to solve the nearest neighbor problem, but in 3D
> space. I tried to do this in 2D and it works perfectly, but apparently it
> doesn't cover the 3D case.
>
> Basically I have a table of 3D points (x, y, z) and would like to do:
>
>     ORDER BY point <-> POINT(0 0 0)
>
> but the distance taken into account should be 3D Euclidean distance. Do I
> have to use ST_3DDistance() for it or is there a faster way?
>
> Thanks in advance!
>
> Regards,
> --
> Bartosz Bekier
>
>
> _______________________________________________
> postgis-users mailing list
> postgis-users at postgis.refractions.net
> http://postgis.refractions.net/mailman/listinfo/postgis-users
>