Can't get contour plots to form/incompatible grids & trouble creating scripts

[Arindam Chakraborty]

Hello Mark,
        If you look at the documentation of vint() at
http://grads.iges.org/grads/gadoc/gradfuncvint.html
it says the syntax is vint(psexpr,expr,top).
Note that psexpr is a grads expression. What it means is, it has to
have the same horizontal grid that expr (shum in your case) belongs
to. When you want a constant 1000 hPa for this value over all the
grids, you have to create a constant field of values 1000. You may use
the const() function to do this job. So,
'open file'
'set region'
'p1000 = const(shum,1000,-a)'
'd vint(p1000,shum,350)'
...



----------------------------
 ARINDAM CHAKRABORTY
 Department of Meteorology
 Florida State University
 Tallahassee, FL-32306, USA
 Tel: +001-850-6443524 (Off)
      +001-850-5758550 (Res)
 Fax: +001-850-6449642
____________________________

On Thu, 18 Aug 2005, Mark Schuster wrote:

> Hello all
>
> I am new to GRADS, and I am working with files that I downloaded from the
> NCEP reanalysis page that are in .nc format.  If I type something like...
>
> sdfopen shum9495.nc
> set lat 60
> set lon 250
> set t 1
> d vint(1000.,shum,350)
>
> I will get the vertically integrated water content at that point which is
> great, but I am more interested in the spatial distribution (contour plot),
> so I make the lat and lon vary.  So if I type
>
> sdfopen shum9495.nc
> set lat 50 70
> set lon 230 250
> set t 1
> d vint(1000.,shum,350)
>
> I get an error about incompatible grids, and I get the error box "this
> program has performed an illegal operation and will be shut down".  I have
> no idea why I don't get a contour plot, as the data I downloaded is within
> the grid that I specify.  I am sure that it is probably a very simple thing
> that I am totally unaware of that I am doing wrong since I am new to grads.
>
> Also, for creating scripts, do I just type it up in notepad, and type run
> script in the grads window?  Extension is suppose to be .gs, but if you
> type it in notepad, it has a .txt extension.
>
> Many thanks!
>
> Mark
>