Return the distance between two points

latlng_distance

    /**
    *   Returns the distance between two given lat / lngs
    *   in miles. 
    *
    *   @params float $lat1
    *   @params float $lng1
    *   @params float $lat2
    *   @params float $lng2
    *   @return float
    */
    public static function calculateDistance($lat1, $lng1, $lat2, $lng2) 
    {
        $theta = $lng1 - $lng2;
        $dist = sin(deg2rad($lat1)) * sin(deg2rad($lat2)) +  cos(deg2rad($lat1)) * cos(deg2rad($lat2)) * cos(deg2rad($theta));
        $dist = acos($dist);
        $dist = rad2deg($dist);
        $miles = $dist * 60 * 1.1515;
        
        return $miles;
    }