PHP: Lat/Lng Distance Calculator

gistfile1.txt

function crb_calculate_location_distance($latitude1, $longitude1, $latitude2, $longitude2) {
	$theta = $longitude1 - $longitude2;
	$miles = (sin(deg2rad($latitude1)) * sin(deg2rad($latitude2))) + (cos(deg2rad($latitude1)) * cos(deg2rad($latitude2)) * cos(deg2rad($theta)));
	$miles = acos($miles);
	$miles = rad2deg($miles);
	$miles = $miles * 60 * 1.1515;
	// $feet = $miles * 5280;
	// $yards = $feet / 3;
	// $kilometers = $miles * 1.609344;
	// $meters = $kilometers * 1000;
	return $miles;
}