Adding MKPolyline

I’m having some trouble adding an MKPolyline to my mapView. I’m trying to add a simply overlay of a blue line that traces changes in the current location. Here is the code:

 //CLLocationManagerDelegate methods
func locationManager(manager: CLLocationManager, didUpdateToLocation newLocation: CLLocation, fromLocation oldLocation: CLLocation) {
    if let oldLocationNew = oldLocation as CLLocation? {
        let oldCoordinates = oldLocationNew.coordinate
        let newCoordinates = newLocation.coordinate
        var area = [oldCoordinates, newCoordinates]
        let polyline = MKPolyline(coordinates: &area, count: area.count)

    func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    func locationManager(manager: CLLocationManager, didFailWithError error: NSError) {

    //MKMapViewDelegate methods

func mapView(mapView: MKMapView, rendererForOverlay overlay: MKOverlay) -> MKOverlayRenderer {
    let pr = MKPolylineRenderer(overlay: overlay)
    if overlay is MKPolyline {
        pr.strokeColor = UIColor.blueColor()
        pr.lineWidth = 5
        return pr


Any help would be appreciated.