public void OnMapReady (GoogleMap googleMap)
        {
            googleMap.MoveCamera (CameraUpdateFactory.NewLatLngZoom (NEWARK, 11));

            images.Clear ();
            images.Add (BitmapDescriptorFactory.FromResource (Resource.Drawable.newark_nj_1922));
            images.Add (BitmapDescriptorFactory.FromResource (Resource.Drawable.newark_prudential_sunny));

            currentEntry = 0;

            groundOverlay = googleMap.AddGroundOverlay (new GroundOverlayOptions ()
                .InvokeImage (images [currentEntry])
                .Anchor (0, 1)
                .Position (NEWARK, 8600f, 6500f));

            transparencyBar.ProgressChanged += (sender, e) => {
                if (groundOverlay != null)
                    groundOverlay.Transparency = (float)e.Progress / (float)TRANSPARENCY_MAX;                    
            };

            googleMap.SetContentDescription ("Google Map with ground overlay.");
        }
        private void PositionPolarBearGroundOverlay(LatLng position)
        {
            if (_polarBearOverlay == null)
            {
                BitmapDescriptor image = BitmapDescriptorFactory.FromResource(Resource.Drawable.polarbear);
                GroundOverlayOptions groundOverlayOptions = new GroundOverlayOptions()
                    .Position(position, 150, 200)
                    .InvokeImage(image);
                _polarBearOverlay = _map.AddGroundOverlay(groundOverlayOptions);

                PolygonOptions rectOptions = new PolygonOptions();

                rectOptions.Add(position);
                rectOptions.Add(new LatLng(37.45, -122.0));
                rectOptions.Add(new LatLng(37.45, -122.2));
                rectOptions.Add(new LatLng(37.35, -122.2));
                // notice we don't need to close off the polygon
                _map.AddPolygon(rectOptions);
            }
            else
            {
                _polarBearOverlay.Position = InMaui;
            }
        }
 private void PositionPolarBearGroundOverlay(LatLng position)
 {
     if (_polarBearOverlay == null)
     {
         var image = BitmapDescriptorFactory.FromResource(Resource.Drawable.polarbear);
         var groundOverlayOptions = new GroundOverlayOptions()
             .Position(position, 150, 200)
             .InvokeImage(image);
         _polarBearOverlay = _map.AddGroundOverlay(groundOverlayOptions);
     }
     else
     {
         _polarBearOverlay.Position = InMaui;
     }
 }
		private void PositionChicagoGroundOverlay(LatLng position)
		{
			if (_chicagoOverlay == null)
			{
				BitmapDescriptor image = BitmapDescriptorFactory.FromResource(Resource.Drawable.monkey);
				GroundOverlayOptions groundOverlayOptions = new GroundOverlayOptions()
					.Position(position, 150000, 200000)
					.InvokeImage(image);
				_chicagoOverlay = _map.AddGroundOverlay(groundOverlayOptions);
			}
			else
			{
				_chicagoOverlay.Position = Location_Chicago;
			}
		}