public override MKOverlayRenderer OverlayRenderer(MKMapView mapView, IMKOverlay overlay) { var polygon = overlay as MKPolygon; if (polygon != null) { var polygonRenderer = new MKPolygonRenderer(polygon) { FillColor = UIColor.LightGray, StrokeColor = UIColor.DarkGray, LineWidth = 3f }; return(polygonRenderer); } return(mapView.RendererForOverlay(overlay)); }