SPACE_TYPE

          CHARACTER*8 SPACE_TYPE

     Define the type of spacing for the contour levels
       LIN       Linear spacings. The Zero contour is always omitted.
       LOG       Exponential spacing
       NONE      No contour levels at all (same as DO_CONTOUR = NO)
       USER      Keep the contour levels specified by command LEVELS
    For LOG case, see HELP LEVELS EXPO in the GreG internal help.

    As  a  backward compatibility, a negative spacing is a convention to use the
    current contour levels, although using SPACE_TYPE  =  USER  should  be  pre-
    ferred.