On Mon, Feb 05, 2007 at 14:47:25 -0500, Mark Stosberg <mark@xxxxxxxxxxxxxxx> wrote: > > This is also interesting. Is this approach practical if I want to index > what's near each of about 40,000 US zipcodes, or the approach mostly > useful if you there are just a small number of fixed points to address? I think the answer depends on what your data model is. If you treat each zip code as having a location at a single point, the earth distance stuff should work. If you are trying to include the shape of each zip code in your model and measure distances to the nearest point of zip codes, then you will probably be better off using postgis.
