Re: Advice on geolocation

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От Bruno Wolff III
Тема Re: Advice on geolocation
Дата
Msg-id 20020726171542.GA19516@wolff.to
обсуждение исходный текст
Ответ на Re: Advice on geolocation  (Chris Albertson <chrisalbertson90278@yahoo.com>)
Ответы Re: Advice on geolocation  ("Roderick A. Anderson" <raanders@acm.org>)
Re: Advice on geolocation  (Chris Albertson <chrisalbertson90278@yahoo.com>)
Список pgsql-general
On Fri, Jul 26, 2002 at 09:33:53 -0700,
  Chris Albertson <chrisalbertson90278@yahoo.com> wrote:
>
> I've done quite a bit of this as I used to work on a GIS
> product.  Given to lat,lon pairs it is not hard to find
> the great circle distance between them.  This assumes a
> spherical Earth but good enough for your purposes as the
> error will be under a few hundred meters

My concern about this is that it will not be indexable. I suspect, but don't
know, that this won't really be an issue for the small number (~5000) points
of data (especially since I expect other constraints to be used in most
queries).

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