function getDistance($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 compact('miles','feet','yards','kilometers','meters'); 

  return $kilometers;

}