From: | Andy Lewis <alewis(at)recruitersonline(dot)com> |
---|---|
To: | Jeff Hoffmann <jeff(at)propertykey(dot)com> |
Cc: | pgsql-general(at)HUB(dot)ORG |
Subject: | Re: Zip Code Proximity |
Date: | 2000-05-18 18:02:41 |
Message-ID: | Pine.LNX.4.20.0005181258230.6117-100000@mail.recruitersonline.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
On Thu, 18 May 2000, Jeff Hoffmann wrote:
> Andy Lewis wrote:
> >
> > Actually I was thinking more on the lines of:
> >
> > select location from test where location @ '((31.6283,93.6347), 1.39)'::circle;
> >
>
> that works just great, assuming that you can accurately calculate the
> radius of the circle that you're searching for.
>
I'll already have the mileage from an html form and the initial
zip. Should work just fine. It doesn't have to be exact just close.
> > If Zylks, LA (lat/lon = 32.9696,93.9801) is also in the DB.
> > The above query should select Zylks since 1.39 * 62.1 = 86 miles approx.
> > 86 miles is about correct for those two zip codes.
> >
> > Wouldn't this be much easier?
>
> to me, the big question is how you're calculating the radius & if you're
> taking into account the curvature of the earth so that 62.1 changes in
> different parts of the country. if you've taken that into
> consideration, great. it's probably going to be ok to flatten the earth
> for an area that size, though.
>
I don't plan on using anymore than a 100 miles, so that should work ok,
I'd think.
> > Is the data type POINT index-able?
> >
>
> unfortunately, not in a really useful way for you. plus, the optimizer
> probably wouldn't use the index any. it's a small data set, something
> around 35k-40k records, right?
>
I'm not sure how many records are in the zip code DB that I currently
have, shouldn't be much more than that though.
Andy
From | Date | Subject | |
---|---|---|---|
Next Message | The Hermit Hacker | 2000-05-18 18:08:56 | Re: The New Slashdot Setup (includes MySql server) |
Previous Message | Benjamin Adida | 2000-05-18 17:42:13 | Re: The New Slashdot Setup (includes MySql server) |