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.