public function coordinatesDistance($lat1, $lng1, $lat2, $lng2, $miles = false)
    {
        $pi80 = M_PI / 180;
        $lat1 *= $pi80;
        $lng1 *= $pi80;
        $lat2 *= $pi80;
        $lng2 *= $pi80;

        $r = 6372.797;
        $dlat = $lat2 - $lat1;
        $dlng = $lng2 - $lng1;

        $a = sin($dlat / 2) * sin($dlat / 2) + cos($lat1) * cos($lat2) * sin($dlng / 2) * sin($dlng / 2);
        $c = 2 * atan2(sqrt($a), sqrt(1 - $a));
        $km = $r * $c;

        return $miles ? ($km * 0.621371192) : $km;
    }