Re: indexing lat lon

"Jonathan Raemdonck" <jonathan_raemdonck(at)hotmail(dot)com> writes:
> These are the steps I take now:
> 1 'draw' a box around the lat/lon position we have as input
> 2 search the DB for all the points in this box
> 3 measure the distance to each point in the box

Right. All you need is an index amenable to step 2.

> Is there a good way of indexing the lat/lon column so lookup is faster?

Yeah, you can store the lat/long as a point, build an rtree index on it,
and use box-overlap as the indexable operator. I seem to recall that
you actually have to store the lat/long as a box of zero size to get
this to work with the present set of rtree-indexable operators. If you
look in the archives you will find some previous similar cases.

regards, tom lane