Finer grid wind interpolation

Arlindo da Silva arlindo.dasilva at GMAIL.COM
Wed Feb 11 14:08:01 EST 2009

On Tue, Feb 10, 2009 at 11:59 PM, Antoy Chang <antoyc at> wrote:

> Hi all.,
> I just wondering if anyone here know how to do the wind field interpolation
> to a finer grid. Sorry for my vague question. Thank You very much for your
> response.

The question for you is how accurate do you want to be? For a quick plot
linear interpolation is fine; poles are always tricky, depending on whether
your the poles are in the center or edge of the gridbox.  Look for the built
in linterp() function in grads v2, and the UDFs re()/regrid2() in grads
 A proper wind interpolation should take as input both u and v components;
currently grads functions can only return one argument, so you would need 2
functions: uinterp(u,v), and vinterp(u,v). I am not aware of any function
implementing vector interpolation in grads, so you would need to write a
user defined function for that. And as of this writing, only grads v1.x
supports UDFs.


Arlindo da Silva
dasilva at
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