The GRIB_ITERATOR_NEXT function gets the next value from an iterator.
            Examples
            See GRIB_GET_VALUES for a general example using the GRIB routines.
            Syntax
            Result = GRIB_ITERATOR_NEXT(Iterid)
            Return Value
            Returns a 3 x N array where the first dimension is [lat, lon, value] if successful; otherwise, a scalar 0 is returned.
            Arguments
            Iterid
            An iterator handle.
            Version History
            
            See Also
            GRIB_ITERATOR_NEW, GRIB_ITERATOR_DELETE