final Map map = mapWidget.getMap();
OSM osm = OSM.Mapnik("Mapnik");
osm.setIsBaseLayer(true);
map.addLayer(osm);
vectorLayer = new Vector("Fence");
map.addLayer(vectorLayer);
markers = new Markers("Markers");
map.addLayer(markers);
map.addControl(new OverviewMap());
map.addControl(new ScaleLine());