Logic Question

[Arlindo da Silva]

On Wed, Mar 25, 2009 at 6:54 PM, Mark Sponsler <msponsler at comcast.net> wrote:
> I need your expert assistance
>
> The goal is to display the greater of 2 variables, comparing them grib
> point by grib point onto a single image in one display operation.  I
> believe that 'if' and '>' can't be used in a define statement, hence the
> dilemma:
>

There is a specific function in B.-J. Tsuang's extension collections (Libbjt):

         http://opengrads.org/doc/udxt/libbjt/

I believe function maxv() does exactly what you want. For example,

ga-> open model
ga-> display maxv(ua(lev=300),ua(lev=100))

will display the maximum u-wind between 300 and 100 hPa. There is also
a similar minv() function.

You can find Libbjt in the recent OpenGrADS v2.0.a5.oga.3 bundle, as
well as in any of the opengrads Win32 Superpacks, and in the
extensions for GrADS v1.9.0-rc1, all available from sf.net:

       http://sourceforge.net/project/showfiles.php?group_id=161773

 There are many very useful functions in Libbjt, take a look.

       Arlindo.

--
Arlindo da Silva
dasilva at alum.mit.edu
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