title: Remove Map Annotation on Button Click (that created annotation)
body: <p>Why will my code not remove the map annotation?</p>
  
  <p>I hit the button and it gets the users location and then pins it to the map.  The problem is that when the button is hit a second, third, .......  time It just keeps adding pins instead of removing the first pin (simulating replacing the pin).</p>
  
  <p>I have tried adding another button (clear pins) and following this thread :http://stackoverflow.com/questions/3027392/how-to-delete-all-annotations-on-a-mkmapview but the app just crashes with no debug info. </p>
  
  <p>But in theory my code should work.  So what am I not understanding?</p>
  
  <pre><code>- (IBAction)getLocation:(id)sender {
      MapAnnotation *ann1 =[[[MapAnnotation alloc] init]autorelease]; 
  
      // remove annotation
      [mapView removeAnnotation:ann1];
  
  
      locationManager = [[CLLocationManager alloc] init];
      locationManager.distanceFilter=kCLDistanceFilterNone;
      locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters;
      [locationManager startUpdatingLocation];
  
      [mapView setMapType:MKMapTypeStandard];
      [mapView setZoomEnabled:YES];
      [mapView setScrollEnabled:YES];
      MKCoordinateRegion region = {{0.0,0.0},{0.0,0.0}};
      region.center.latitude = locationManager.location.coordinate.latitude;
      region.center.longitude = locationManager.location.coordinate.longitude;
      region.span.longitudeDelta = 0.005f;
      region.span.latitudeDelta = 0.005f;
      [mapView setRegion:region animated:YES];
      [mapView setDelegate:sender];
  
      MKCoordinateRegion location1;
      location1.center.latitude =locationManager.location.coordinate.latitude;
      location1.center.longitude= locationManager.location.coordinate.longitude;
      location1.span.longitudeDelta=0.1;
      location1.span.latitudeDelta =0.1;
  
  
      // Add Annotation
      //MapAnnotation *ann1 =[[MapAnnotation alloc] init];
      ann1.title=@"You Parked Here";
      ann1.subtitle=@"";
      ann1.coordinate= location1.center;
      [mapView addAnnotation:ann1];
  
  }
  </code></pre>