contour_mapped.push_back(vtkPolyDataMapper::New());
contour_mapped.back()->ImmediateModeRenderingOn();
contour_mapped.back()->ScalarVisibilityOff( );
contour_mapped.push_back(vtkPolyDataMapper::New());
contour_mapped.back()->ImmediateModeRenderingOn();
contour_mapped.back()->ScalarVisibilityOff( );