zt plots and sigma depth

[Steve Cousins <cousins@xxxxxxxxxxxxxxxxxxxxxxx>]

I am working on getting zt plots to work with sigma coordinate depths and
it is very close.  The data set has a 3D variable called depth_at_sigma
contains the depth at each X,Y,Z grid point.  

My first attempt to plot zt was to edit draw_2d.tmpl:

[% IF args.do_shade %]
    go preplot_setup
    [% IF args.view == 'zt' %]
        [% args.fill_type %]/levels=[% args.fill_levels %]/set [% args.variable_name.0 %], depth_at_sigma, t
    [% ELSE %]
        [% args.fill_type %]/levels=[% args.fill_levels %]/set [% args.variable_name.0 %]
    [% END %]
    .
    .
    .
[% END %]

This actually almost works.  It puts Depth on the X axis of the plot and T
on the Y axis.  The depths seem to show up correctly but I'd like to swap
the Axes.  So, I reversed the order t and depth_at_sigma above but then it
produces the following error:

=====================================================================

Adding an acceptable error string: "*** NOTE: ".
         NOAA/PMEL TMAP
         FERRET v5.53  
         Linux(g77) 2.4.x - 09/26/03
         14-Sep-04 12:15     

 yes? cancel mode verify
 yes? cancel mode interp
 yes? define symbol refmap_xhi = 172.0
 yes? define symbol refmap_yhi = 29.0
 yes? define symbol land_type = shade
 yes? define symbol refmap_xlo = 172.0
 yes? define symbol jnl_t = ARRAY(0x8cd8970)
 yes? define symbol refmap_view = point
 yes? define symbol refmap_ylo = 29.0
 yes? define symbol variable_name_0 = nh4
 yes? define symbol fill_type = fill
 yes? define symbol jnl_x = ARRAY(0x8cd87e4)
 yes? define symbol variable_name = ARRAY(0x88605cc)
 yes? define symbol jnl_y = ARRAY(0x8cd891c)
 yes? define symbol jnl_z = ARRAY(0x8cd8934)
 yes? define symbol diag_direction = down
 yes? define symbol dataset_name_0 =
/usr2/fer_dsets/descr/pacific-roms-90-01.des
 yes? define symbol dataset_name = ARRAY(0x88605f0)
 yes? define symbol rank = 2
 yes? canc data/all
 yes? go std_initialize "/usr2/fer_dsets/descr/pacific-roms-90-01.des" "1"
"1" "nh4"
 yes? set region/x="172.0"/y="29.0"/z="-1":"-20"/l="1":"144"
 yes? set win/size=.5
 yes? GO "/tmp/lasgo24933952610.jnl"
  **ERROR: inconsistent sizes of data regions: X coord field lies
           in different plane from data to be plotted
 CONTOUR/FILL/levels=30/set nh4, t, depth_at_sigma
 Command file, command group, or REPEAT execution aborted

=====================================================================

the contents of /tmp/lasgo24933952610.jnl are (cleaned up a bit) :

=====================================================================

can view
define view/x=0.30,1/y=0,1 vt
define view/x=0,.35/y=.02,.96 vb

set view vt

! SDC: Dealing with Sigma (actually S-coordinates in this case) 

   set MEMORY/SIZE=20.0
      
   DEFINE AXIS/Z=-5000.0:0.0:10.0/UNIT=meters/DEPTH zdepth 
   LET varonsigma= ZAXREPLACE(nh4,depth_at_sigma,z[gz=zdepth])
   LET var_at_depth = varonsigma[  ]

   let var_kend = `var_at_depth,RETURN=KEND`
   go preplot_setup
    
   fill/levels=30/set nh4, t, depth_at_sigma
    
   go postplot_setup
   palette default
     
   ppl title,0.15,averaged ammonium (mMol N m-3)
   ppl fill

! overlay the land mask
go noaa_text 0 1.1
set view vb

=====================================================================

When I was doint this with xz and yz I was trying to use 'X' and 'Y'
variables and it was suggested that I put:

	let xx = x[gx=$4]
	let yy = y[gy=$4]

in std_initialize.jnl and then use xx and yy instead of 'X' and 'Y'.  This
worked.  I don't think this is the same problem now but I did try:

	let tt = l[gt=$4]

and then I tried:

 [% args.fill_type %]/levels=[% args.fill_levels %]/set [% args.variable_name.0 %], tt, depth_at_sigma

but I get this same error about the inconsistent sizes of data regions.

I'm sorry for the very long email.  Does anyone have an idea about how
this should best be done?

Thanks,

Steve
______________________________________________________________________
 Steve Cousins, Ocean Modeling Group    Email: cousins@umit.maine.edu
 Marine Sciences, 208 Libby Hall        http://rocky.umeoce.maine.edu
 Univ. of Maine, Orono, ME 04469        Phone: (207) 581-4302