I have a bunch of lat/longs in my database and i'd like to perform a search to find the lat/longs within a specified distance. I found the following code, but I'm not sure how to port it to do that instead of calculate the distance between two points. any ideas?
// Function takes latitude and longitude
// of two places as input and prints the
// distance in miles and KMs.
function toMiles($lat1, $lon1, $lat2, $lon2)
// Formula for calculating distances
// from latitude and longitude.
$dist = acos(sin(deg2rad($lat1))
* cos(deg2rad($lon1 - $lon2)));
$dist = rad2deg($dist);
$miles = (float) $dist * 69;
// To get kilometers, multiply miles by 1.61
$km = (float) $miles * 1.61;
// This is all displaying functionality
$display = sprintf("%0.2f",$miles).' miles' ;
$display .= ' ('.sprintf("%0.2f",$km).' kilometers)' ;
return $display ;