title: ionic 2 use zone Ngzone()
body: <p>hi i try to use Zone on my ionic2 app : </p>
  
  <p>i create a provider who take location of my device</p>
  
  <pre><code>import { Injectable,NgZone  } from '@angular/core';
  import { Geolocation, Geoposition } from '@ionic-native/geolocation';
  import 'rxjs/add/operator/filter';
  
  
  
  @Injectable()
  export class LocationTracker {
  
    public watch: any;    
    public lat: number = 0;
    public lng: number = 0;
  
    constructor(public zone: NgZone,
                public geolocation:Geolocation) {
                console.log('Hello LocationTracker Provider');
    }
  
    startTracking() {
    console.log("provider startTracking")  
  
  
          let options = {
            frequency: 3000, 
            enableHighAccuracy: true
          };
  
         this.watch = this.geolocation.watchPosition(options).filter((p: any) =&gt; p.code === undefined).subscribe((position: Geoposition) =&gt; {
  
                       // Run update inside of Angular's zone
                        this.zone.run(() =&gt; {
                        this.lat = position.coords.latitude;
                        this.lng = position.coords.longitude;
  
                 });
  
        });
    }
  
  
  
  }
  </code></pre>
  
  <p>In the  home view html, i have access to the zone with {{locationTracker.lat}}, but in my home component (who call this provider) i don't know how i can't have access to the zone </p>
  
  <p>i try this</p>
  
  <pre><code> this.locationTracker.lat
  </code></pre>
  
  <p>but it's undefined </p>
  
  <p>can't you help my ?</p>