Re: How to define evenly-spaced axis with unevenly-intervaled number

["Mark Verschell" <markv@xxxxxxxxxxxxxxxxxxx>]

Hi Julia,

Actually, 2 ways come to mind on how to accomplish what you want.

The first way is one I have used often and is not exactly what you asked for.
What you do is split the plot into 2 depth ranges (surface and deep) and put
them on the same plot. You do this with the Ferret Go tool: split_z.jnl:
! split_z.jnl
! 10/95 - based on a script submitted by Joachim Dengg
! Description: make a CONTOUR,SHADE, or FILL plot with a split vertical axis
! producing a "magnified" view of the near-surface waters

! usage:               $1       $2    $3  $4  $5   $6     $7
!   yes? GO split_z command  qualifs var top mid bottom split
! $1 - the plot command (SHADE,FILL or CONT)  (default, "FILL")
! $2 - qualifiers to the plot command - /LEVELS and /PALETTE (default, none)
! $3 - the variable to be plotted (use quotation marks if it contains commas)
! $4 - the depth at the      top    of the plot (default=0)
! $5 - the depth at the split point of the plot (default=1000)
! $6 - the depth at the    bottom   of the plot (default=5000)
! $7 - the fraction of the page given to the upper viewport (default=0.33)

! example:
!   yes? SET DATA levitus_climatology
!   yes? SET WINDOW/ASPECT=1
!   yes? go split_z FILL "/lev=(0,4,.5)(0,30,2)" "temp[X=160W,Y=45S:45N]" 0 500
4000 0.4
! Note 1: a taller, thinner window looks nicer ...
!         yes? SET WINDOW/ASPECT=1
! Note 2: this procedure will not work in a viewport since it uses viewports

The second way would give you exactly what you want, but it wouldn't be easy.
First, you would have to define the depth axis in your grid with a regular
depth level (e.g. 1,2,3....). Then plot the data with the ppl axlabp,,0 to turn
off the labels. Then you would have to hand label each tic on the depth axis
with its true depth (using ppl labs). You could make a GO tool out of this once
you have it figured out the first time.

I would go with the first way, this is very standard in oceanography. To
customize the plots do what I do: copy the split_z.jnl to my local directory,
change the name, and edit the file.

Good Luck! Mark

-- 
-------------------------------------------------------------------------------

	      Mark Verschell (verschell@coaps.fsu.edu)
	      Center for Ocean and Atmospheric Prediction Studies
	      Florida State University
              2035 E. Paul Dirac Drive
              R.M. Johnson Bldg. - Suite 200
	      Tallahassee, FL  32306-3041
	      (904) 644-6532              (904) 644-4841 (fax)