code: @SuppressWarnings("unchecked")
  	@Pure
  	public Tree<RoadPolyline, ?> getInternalTree() {
  		if (this.roadSegments instanceof GISTreeSet<?, ?>) {
  			return ((GISTreeSet<RoadPolyline, ?>) this.roadSegments).getTree();
  		}
  		return null;
  	}
docs: Replies the internal data-structure as tree.
  
  @return the internal data-structure as tree.