20000225: gdplot problem

>From: Clint Rowe <address@hidden>
>Organization: .
>Keywords: 200002260255.TAA21708

>Chiz,
>
>I've searched the support e-mail and documentation and can't figure 
>why this doesn't work.  In GDPLOT, I want to plot THTE (which is not 
>available in the grid file I'm using) using different colors, etc for
>contour lines and fills over parts of the range of values. So I've got:
>
>gfunc = thte(mul(.9823,pres@0%none);tmpc;dwpc)//the ! the
>
>However, when I run the script, I get 
>
>GRID IDENTIFIER: 
>    PLOT LEVEL VCORD PARM                       WPARM
>       1 9823  SGMA  THTE(MUL(.9823,PRES@0%NONE)                           
>       2 9823  SGMA   THE                       KNTV(WND)                  
>
> GAREA:  33;-110;50;-85                                                       
>    
> [DG -7]  Input grid THE ^000225/1200F006 @9823 %SGMA cannot be found.
> [GDPLOT 2]  The requested scalar/vector cannot be computed.
> 
>I can do this in GDCNTR without a problem, however, I would have to 
>completely rework the flow of the script.  Is there a way to specify
>a useable short name for a gfunc in GDPLOT?
>
>Clint
>
>====================================================================
>Clinton M. Rowe
>Associate Professor 
>Meteorology/Climatology Program                  phone:(402)472-1946
>Department of Geosciences                          fax:(402)472-4917
>University of Nebraska-Lincoln                        address@hidden
>

Clint,

this function works:
GFUNC    = thte(mul(pres,.9823);tmpc;dwpc)//tst1!tst1
whereas this doesn't:
GFUNC    = thte(mul(emsl@0%none,.9823);tmpc;dwpc)//tst1!tst1

What is happening for you is that the THE grid you produce internally is
not on level 9823 and gvcord SGMA (using gddiag will probably show that
your THE grid results in a vertical coordinate of NONE and a glevel
of 0:9823.

The thing here is that when you do the computation, the resulting
grid is not refered to as the same level/cordinate as your input
tmpc and dwpc grids are. Rather, the resultant grid level is
the 2 levels being used, and the coordinate of the inline substitution.

The following will probably work:
gfunc = thte(mul(.9823,pres@0%none);tmpc;dwpc)//the!the@0:9823%sgma

Steve Chiswell
Unidata User SUpport