protected override void OnCreate(Bundle savedInstanceState) { base.OnCreate(savedInstanceState); // USGS Base map: http://basemap.nationalmap.gov/arcgis/rest/services/USGSTopo/MapServer string url = "http://basemap.nationalmap.gov/arcgis/services/USGSTopo/MapServer/WmsServer?"; string layers = "0"; HttpWmsTileDataSource wms = new HttpWmsTileDataSource(0, 14, BaseProjection, false, url, "", layers, "image/png8"); RasterTileLayer wmsLayer = new RasterTileLayer(wms); // Calculate zoom bias, basically this is needed to 'undo' automatic DPI scaling, // we will display original raster with close to 1:1 pixel density double zoomLevelBias = Math.Log(MapView.Options.DPI / 160) / Math.Log(2); wmsLayer.ZoomLevelBias = (float)zoomLevelBias; MapView.Layers.Add(wmsLayer); // Animate map to map coverage MapView.SetFocusPos(BaseProjection.FromWgs84(new MapPos(-100, 40)), 1); MapView.SetZoom(5, 1); }