Calculate Distance Between Two Points using PHP

<?php
      function my_getDistanceBetweenPoints($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');
      }
      $point_A = array('lat' => 40.770623, 'long' => -73.964367);
      $point_B = array('lat' => 40.758224, 'long' => -73.917404);
      $show_distance = my_getDistanceBetweenPoints($point_A ['lat'], $point_A ['long'], $point_B ['lat'], $point_B ['long']);
      foreach ($show_distance as $unit => $value) {
            echo $unit.': '.number_format($value,4).'<br />';
      }
?>