public function exactDistanceSLCFrom(LatLng $coord, $unit = UnitsType::KILOMETERS)
    {
        $lat1 = $this->getLat();
        $lat2 = $coord->getLat();
        $lon1 = $this->getLng();
        $lon2 = $coord->getLng();

        $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;

        switch ($unit) {
            case UnitsType::KILOMETERS:
                $distance = $miles * 1.609344;
                break;
            case UnitsType::NAUTIC_MILES:
                $distance = $miles * 0.8684;
                break;
            case UnitsType::MILES:
            default:
                $distance = $miles;
        }
        return $distance;
    }