Re: Special query type for Spatial DB

"Paul" <paul_at_not.a.chance.ie> wrote in message news:MPG.1a72216b23a01fd99898a2_at_news1.eircom.net...
>
> pkl_at_mailme.dk says...
>
> > I can not see how this problem is related to the travelling salesman
> > problem. Would you care to elaborate?
>
>
> From the OP
>
> -----------
> a)Given a bounded region in space, find me a cluster of 50 pulsars that
> are closest to each other.
> b)Given the state of California, find me a group of 10 fire-stations
> that are closest to each other.
> ------------
>
>
> I assumed in this case that the OP was asking for clusters of pulsars
> and/or firestations that were nearer relative to each other than to all
> other clusters of 50/10 pulsars/firestations.
>
> It seems to me that this is just a reformulation of the travelling
> salesman problem, but would be prepared to listen to someone who
> disagreed.

Finding the shortest path in a weighted graph is not the same as finding a set of N points in a graph, or, alternatively, in metric space such that sum of the distances between all the pairs is minimal. Note that "sum of the distances" can have various definitions too. Received on Fri Jan 16 2004 - 17:41:59 CET