Re: nearest neighbor search from xyz coordinates - Mailing list pgsql-general

From Serge Fonville
Subject Re: nearest neighbor search from xyz coordinates
Date
Msg-id 680cbe0e0810270426t567cfc2bia38e0d570f6b91f3@mail.gmail.com
Whole thread Raw
In response to nearest neighbor search from xyz coordinates  (Andreas Jochem <andruit@gmx.de>)
List pgsql-general
What exactly do you want to measure, since values can be compared easily by a where clause
If you would want for example all rows within a spherical distance
you will either have to write a stored procedure (which takes 4 parameters x,y,z,distance)
Or manually compare each corodinate to the distance

Regards,

Serge Fonville 

On Mon, Oct 27, 2008 at 11:50 AM, Andreas Jochem <andruit@gmx.de> wrote:
Hello,

I have a table containing x y z coordinates. But I have no geometry column?
Is it possible to find the k nearest neighbors of any point. Is there something like a kd-tree Index in postgres???

I know, if i had a geometry column I could make use of the distance function to find the k nearest neighbors. But my table has millions of records, thus it would take a very long time to use the distance function for each point.

Thanks in advance.

Andi

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