[gradsusr] Fwd: Plot vector - geographic X trigonometric system

[Gabriel - ud Carvalho]

---------- Forwarded message ----------
From: Gabriel - ud Carvalho <gabriel.ud at gmail.com>
Date: 2010/9/27
Subject: Plot vector - geographic X trigonometric system
To: gradsusr at gradsusr.org, GRADSUSR at list.cineca.it


Hello you all!
Here is the deal:
In my data, the wind direction is in degrees, with a geographic
representation (wich means that 0 is at the north and goes clockwise),
the problem is that to display this data with 'gxout vector', I have to
decompose it in 'u' and 'v'. In order to do this, I have to use the
trigonometric functions 'sin' and 'cosin'. The problem is here, these
functions assume that the input data is with a trigonometric representation
(wich means that 0 degrees is eastside and goes anti-clockwise),butthey
aren´t, so, it got all messed up.

I don´t know what to do,but I believe that this is a common problem,
I hope someone will know the answer...

Sorry about my poor english,

My best regards,
Gabriel Carvalho
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