地図上の 2 点間の距離を計算します

class GeoHelper
{
 /**
 * @param int $lat1
 * @param int $lon1
 * @param int $lat2
 * @param int $lon2
 * @param string $unit
 * @return
*/
 public static function distance($lat1, $lon1, $lat2, $lon2, $unit = "K")
 {
 $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;
 $unit = strtoupper($unit);

 if ($unit == "K") {
 return ($miles * 1.609344);
 } else
 if ($unit == "N") {
 return ($miles * 0.8684);
 } else { //mi
 return $miles;
 }
 }

 /**
 *
 * @param string $address
 * @param string $apikey
 * @return array [1]:lat [0]:lng
*/
 public static function getLatLng($address, $apikey)
 {
 $find = array("n", "r", " ");
 $replace = array("", "", "+");
 $address = str_replace($find, $replace, $address);
 $url = 'http://maps.google. com/maps/geo?q=' 。 $アドレス . '&key=' 。 $apikey .
 '&sensor=false&output=xml&oe=utf8';
 $response = self::xml2array($url);
 $座標 = $response['kml']['Response']['Placemark'][' Point']['座標'];
 if (!empty($座標)) {
 $point_array = Split(",", $座標);
 return $point_array;
 }
 }
}