RGMAP /PERCENT

        [GREG2\]RGMAP /PERCENT P1

    Computes M=MAX(ABS(min),ABS(max)) of the data to be  contoured.  Contour
    levels  selected with LEVELS are multiples of P1 percent  of M.  E.g. if
    P1 = 10  and  LEVELS 1 2 5 9,  the contour levels are 10, 20, 50 and 90%
    of the peak value.