You can use the formula to figure out how many zip codes are within the radius
Here's a snippet of old code that did that:
$radius = 50; // in miles
$uchk = db_query("SELECT uz.zip FROM user_zip WHERE uid=$visitor[uid]");
if(db_numrows($uchk) == 1) {
list($vz) = db_rows($uchk);
$zchk = db_query("SELECT latitude,longitude
FROM z_data_zips WHERE zip=$vz");
list($vlat,$vlong) = db_rows($zchk);
db_free($zchk);
$zips = db_query("SELECT z.zip FROM data_zips
z WHERE CEIL(69*DEGREES(ACOS(SIN(RADIANS(z.latitude)) *
SIN(RADIANS($vlat)) + COS(RADIANS(z.latitude)) * COS(RADIANS($vlat)) *
COS(RADIANS(z.longitude - $vlong))))) < $radius");
$ziplist = "";
if(db_numrows($zips) > 0) {
while(list($zip) = db_rows($zips)) {
$ziplist .= "'$zip',";
}
db_free($zips);
$ziplist =
substr($ziplist,0,strlen($ziplist)-1);
$query .= " user_zips IN($ziplist)";
}
}
db_free($uchk);
On 12/6/07, Daniel Brown <parasane@xxxxxxxxx> wrote:
> On Dec 6, 2007 11:02 AM, mike <mike503@xxxxxxxxx> wrote:
> [snip!]
> > 1) download ZCTA (the text version) from
> > http://www.census.gov/geo/www/gazetteer/places2k.html
> [snip!]
>
> How you say? Son of the bitch.
>
> Well, my database still has more information, including nearby ZIP
> codes, et cetera. It's about 38MB, total.
>
> Still.... son of the son of the son of the bitch. Great-grandson
> of the bitch.
>
> --
> Daniel P. Brown
> [Phone Numbers Go Here!]
> [They're Hidden From View!]
>
> If at first you don't succeed, stick to what you know best so that you
> can make enough money to pay someone else to do it for you.
>
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