for(GridSampleDimension band:bands){
bandsNames.add(band.getDescription().toString());
}
// look for an interpolation extension
final ExtensionItemType extensionItem=extensions.get("rangeSubset");
assert extensionItem!=null; // should not happen
final RangeSubsetType range = (RangeSubsetType) extensionItem.getObjectContent();
for(RangeItemType rangeItem: range.getRangeItems()){
// there you go the range item
// single element
final String rangeComponent=rangeItem.getRangeComponent();