This function copies the information stored in a current region or period to a new region or period and generates a new id. It is useful when the user wishes to further subset a region (period) in multiple ways. 
            Examples
            In this example, we first subset a grid with EOS_GD_DEFBOXREGION, duplicate the region creating a new region ID, regionID2, and then perform two different vertical subsets of these (identical) geographic subset regions:
            regionID = EOS_GD_DEFBOXREGION(gridID, cornerlon, cornerlat)
            regionID2 = EOS_GD_DUPREGION(regionID)
            regionID = EOS_GD_DEFVRTREGION(gridID, regionID, "Pressure",$ 
               rangePres)
            regionID2 = EOS_GD_DEFVRTREGION(gridID, regionID2, $
               "Temperature", rangeTemp)
            Syntax
            Result = EOS_GD_DUPREGION(regionID)
            Return Value
            Returns new region or period ID or FAIL (–1) if the region cannot be duplicated.
            Arguments
            regionID
            Region or period id (long) returned by EOS_GD_DEFBOXREGION or EOS_GD_DEFVRTREGION.
            Keywords
            None
            Version History