title: How to move marker over map in ionic2?
body: <p>In this code I try to move <code>marker</code> as I change location but it seems something is wrong.marker is not replacing. </p>
  
  <pre><code>declare var google;
  @Component({
    selector: 'page-page1',
    templateUrl: 'page1.html',
    providers: [Geolocation]
  })
  export class Page1 {
    @ViewChild('map') mapElement: ElementRef;
    map: any;
    public marker =[];
    public lat;
    public lng;
    public speed = '0';
    public watch: any;
  
    constructor(public navCtrl: NavController, public Geolocation: Geolocation, public zone: NgZone,
    ){      }
  ionViewDidLoad(){
    this.loadMap();
    this.startTracking();        
    }
    loadMap(){
            this.Geolocation.getCurrentPosition().then((position) =&gt; {
        let latLng = new google.maps.LatLng(position.coords.latitude, position.coords.longitude);
  
        let mapOptions = {
          center: latLng,
          zoom: 17,
          mapTypeId: google.maps.MapTypeId.ROADMAP
        }     
        this.map = new google.maps.Map(this.mapElement.nativeElement, mapOptions);
   this.addMarker();
      }, (err) =&gt; {
        console.log(err);
      });      
    }
  
    startTracking() {
    let config = {
      desiredAccuracy: 0,
      stationaryRadius: 20,
      distanceFilter: 10, 
      debug: true,
      interval: 2000 
    };     
  let options = {
    frequency: 3000, 
    enableHighAccuracy: true
  };     
  this.watch = this.Geolocation.watchPosition(options).filter((p: any) =&gt; p.code === undefined).subscribe((position: Geoposition) =&gt; {
    this.zone.run(() =&gt; {
      this.lat = position.coords.latitude;
      this.lng = position.coords.longitude;
      this.marker[0].lat= position.coords.latitude;
      this.marker[0].lng= position.coords.longitude;
      this.speed =( +position.coords.speed*3.6 ) + 'Km/h';
    });
  
  });
  
  }
  addMarker(){
  
   let marker = new google.maps.Marker({
      map: this.map,
      animation: google.maps.Animation.DROP,
      position: this.map.getCenter()
    });
  
   this.marker.push(marker);
   console.log(this.marker);
  }
  }
  
  }
  </code></pre>