[GRASS-user] drawing wind vectors

GRASS GRASS user
1

Hi everybody!

I have 2 files, containing u and v component of wind vector respectively. Is there any simple way to plot the wind field?

thank you as usual,

···

–

Alberto Pettazzi

MeteoGalicia - Departamento de Climatología y Observación

Consellería de Medio Ambiente e Desenvolvemento Sostible

Área Central, Local: L-31-C. Polígono de Fontiñas

15703 Santiago de Compostela. A Coruña

Teléfono: +34-981-957463

e-mail: alberto.pettazzi@meteogalicia.es

2

On Thu, 2008-11-20 at 14:10 +0100, Alberto Pettazzi wrote:

Hi everybody!

I have 2 files, containing u and v component of wind vector
respectively. Is there any simple way to plot the wind field?

thank you as usual,
--

Alberto Pettazzi

Hi!

If I got it right then you should have a look at GRASS' module m.cogo
and QGIS' "Azimuth and Distance Plugin".

Regards, Nikos

3

How are the components formatted?

2008/11/20 Nikos Alexandris <nikos.alexandris@felis.uni-freiburg.de>:

On Thu, 2008-11-20 at 14:10 +0100, Alberto Pettazzi wrote:

Hi everybody!

I have 2 files, containing u and v component of wind vector
respectively. Is there any simple way to plot the wind field?

thank you as usual,
--

Alberto Pettazzi

Hi!

If I got it right then you should have a look at GRASS' module m.cogo
and QGIS' "Azimuth and Distance Plugin".

Regards, Nikos

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4

Alberto Pettazzi wrote:

<font face="Times New Roman">Hi
everybody!<br>
<br>
I have 2 files, containing u and v component of wind vector
respectively. Is there any simple way to plot the wind
field?<br>
<br>
thank you as usual,<br>
</font>
<div class="moz-signature">-- <br>

[please post in plain text, html makes it hard for some of us to read...]

Use the d.rast.arrow module. See the help page for conversion of u,v to
magnitude,direction. (assuming you can make u,v into raster maps; what
form is the data in?)

d.rast.arrow screenshot here:
  http://grass.osgeo.org/screenshots/raster.php

In Matlab this is known as a quiver plot, here is a addon for Octave to
do that with free software:
  http://octplot.sourceforge.net/quiver.html

I had thought for a while to add to d.rast.arrow wind barb rendering, and
with the advent of GDAL reading the WMO's GRIB format there is a bit more
reason to do that. For now the zyGrib program is nice to look at those:
  http://zygrib.free.fr/

Hamish