Re: Radial searches of cartesian points?

On Thu, Jan 5, 2012 at 11:01 AM,  <thatsanicehatyouhave@mac.com> wrote:
> Hi,
>
> I have a data set of several hundred thousand points. Each point is saved as a three dimensional coordinate, i.e. (x,
y,z). What I'd like to do is given a point in that space, get a list of all of the points in the table within some
radius.
>
> I'm familiar with the q3c package that does this for points that lie on a sphere, but is there something comparable
forradial searches on 3D cartesian points? Speed is definitely an issue given the number of points I have. 
>
> Thanks for any suggestions!

see:
http://www.postgresql.org/docs/9.1/interactive/cube.html

and pay special attention to gist indexing portions.  cube only
indexes box operations, but you can cull the sphere using 3d distance
formula for points between inner and outer bounding cube.

merlin