func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {

//user's current location
let nowlocation = locations.last
userLocations.append(nowlocation!)

print("HERE IS THE LOCATION ARRAY")
print(userLocations)

//show the current location region
let center = CLLocationCoordinate2D(latitude: nowlocation!.coordinate.latitude, longitude: nowlocation!.coordinate.longitude)
let region = MKCoordinateRegion(center: center, span: MKCoordinateSpan(latitudeDelta: 0.7, longitudeDelta: 0.7))
self.mapView.setRegion(region, animated: true)
drawRoute(locationArray: userLocations)
}

func drawRoute(locationArray: [CLLocation]) {
if (locationArray.count) > 1 {
    var destinationLocIndex = (locationArray.count) - 1
    var startLocIndex = (locationArray.count) - 2

    let destinationloc = locationArray[destinationLocIndex].coordinate
    let startLoc = locationArray[startLocIndex].coordinate

    var routeArray = [startLoc, destinationloc]
    //test if the function works well or not
    print(routeArray)
    var geodesicLine = MKGeodesicPolyline(coordinates: routeArray , count: routeArray.count)
    mapView.add(geodesicLine, level: .aboveRoads)

}