[snip]
we are working on a small project which needs to calculate the closest
distances from an address and/or zipcode entered into a search box. It
will read from a MySQL database of companies, which store their address
and zipcodes.
looking for the best way to approach this. I've seen some zipcode Perl
modules on Cpan, but nothing for helping calculation distances. Can
someone point me in the right direction to accomplish this ... thx's :)
[/snip]
We have started storing latitude and longitude coordinates on our
databases which lends itself to distance calculations. For example, here
is a PHP function which performs the distance calculation
function distance($lat1, $lon1, $lat2, $lon2) {
$theta = $lon1 - $lon2;
$dist = sin(deg2rad($lat1)) * sin(deg2rad($lat2)) +
cos(deg2rad($lat1)) * cos(deg2rad($lat2)) * cos(deg2rad($theta));
$dist = acos($dist);
$dist = rad2deg($dist);
$miles = $dist * 60 * 1.1515;
return $miles;
}
You may be able to do it entirely in a query by utilizing MySQL's math
functions;
http://dev.mysql.com/doc/refman/5.0/en/mathematical-functions.html
HTH
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