15.64.49.6  LOGARITHMIC   - Log scale is used.  Each decade may be divided
into  subintervals  corresponding  to  the  leading  digit  of  the  scale
(1,2...,9).  -LOGARITHMIC generates a log scale for negative values.
  *  LABELS=n1,n2..   -  Specify  which  subintervals  within a decade are
     labeled (2-9).  ALL labels all  subintervals  while  NONE  labels  no
     subintervals.  If you specify NONE then no subintervals are labelled.
     If EXPONENTIAL is specified exponential notation is used.
  *  TICKS=n1...   -  specifies  which  subintervals  have unlabeled ticks
     (2-9).  ALL puts ticks on all subintervals while NONE draws no ticks.
     SHORT|LONG  determine  whether  labelled ticks are short or long.  If
     unspecified LONG is assumed.   Labelled  ticks  at  each  decade  are
     always long.
  *  DECADES=n  - (1 to 31) Specifies how often decades are labelled.  For
     example DECADES=2 labels every other decade.
  *  SUBTICKS=n   -   (0-9)   Specifies  how  many  subticks  are  between
     subinterval ticks.  If n is greater than 0 then long ticks are  drawn
     at for each interval and n short subticks are drawn in between.
If  unspecified  labels,  and  ticks  are  picked  for "pleasing" results.
Generally if less than one half decade is plotted  the  rules  for  making
linear  scales  and  ticks  are  followed.   Otherwise a maximum of 6 or 7
labels are produced.  Exponential notation is only used  if  specified  or
when  the  the  label  would  exceed  6  digits or more than 3 decades are
plotted.