/**
  * Get the contour label format. Use associated <code>ContourLineAttribute</code> if it exists and
  * has labelFormatOverrideen set to <code>false</code>.
  */
 public String getLabelFormat() {
   if (attr_ != null && attr_.isLabelFormatOverridden()) {
     return attr_.getLabelFormat();
   } else {
     return labelFormat_;
   }
 }