This sample application shows how you can manipulate individual layers of the map with track shapes by utilizing the AfterLayerDraw and AfterLabelsOfLayersDraw events raised by the Map.

Draw a track polygon and notice that the states will be erased from the map.  If you draw a track rectangle it will erase the states and roads from the map but leave the cities in tact.  Finally if you draw a track ellipse it will remove all of the layers and labels from the map.