Map is loaded but Polyline are not draw in the map in ionic3?

Ionic Framework ionic-v3
1

Hi
I am working in an App in Ionic 3 that shows current position in the map as well click start track button we have to add polyline between the lat and lang.i know there are some ways to draw polylines my idea is to extract the lat, long coordinates of the marker, save them in an array and then set that as a “path” to draw the Polyline but I’m having problems polylines are not drawn in the map. check our below code

loadMap(){

    this.geolocation.getCurrentPosition().then((position) => {
      let latLng = new google.maps.LatLng(position.coords.latitude, position.coords.longitude);
      let mapOptions = {
        center: latLng,
        position: latLng,
        zoom: 15,

        mapTypeId: google.maps.MapTypeId.ROADMAP
      }

      this.map = new google.maps.Map(this.mapElement.nativeElement, mapOptions);
      this.addMarker();

    }, (err) => {
      console.log(err);
    });
  }

  startTracking() {

    this.isTracking = true;
    this.trackedRoute = [];
 
    this.positionSubscription = this.geolocation.watchPosition()
      .pipe(
        filter((p) => p.coords !== undefined) //Filter Out Errors
      ).subscribe(data => {
        setTimeout(() => {
          this.trackedRoute.push({ lat: data.coords.latitude, lng: data.coords.longitude });
          this.redrawPath(this.trackedRoute);
        }, 0);
      });
  }
 
  redrawPath(path) {
    if (this.currentMapTrack) {
      this.currentMapTrack.setMap(null);
    }
 
    if (path.length > 1) {
      this.currentMapTrack = new google.maps.Polyline({
        path: path,
        geodesic: true,
        strokeColor: '#ff00ff',
        strokeOpacity: 1.0,
        strokeWeight: 3
      });
      this.currentMapTrack.setMap(this.map);
    }
  }