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Re: [ferret_users] Got Vectors?



Dear Hein

thank you so much for your incredibly helpful explanation! It makes complete sense now...

Thanks again!

          L.



On Wed, Feb 13, 2013 at 11:18 PM, Hein Zelle <hein.zelle@xxxxxxxxxxxxx> wrote:
Dear Luke M,

> I am trying to make a plot using surface currents (water_u & water_v) data
> (please see below for dataset details), but I'm not exactly sure how to
> approach this.

the basic steps are, given a u and v component from your data file:

let current_spd = (u^2+v^2)^0.5

shade /lev=20 current_spd
vector /overlay u,v
go land

if you want to normalize the vectors to a length of 1, simply divide
the components by the speed value:

let unorm = u / current_speed
let vnorm = v / current_speed
vector /overlay unorm, vnorm

See the ferret documentation for further options to the vector
command.  You can use /aspect to adapt for different plot aspect
ratios, and /length to adjust the size of the arrows.  /xskip and
/yskip are used to control the arrow density.

Kind regards,
     Hein


--

Dr. Hein Zelle
Senior consultant meteorology & oceanography
BMT ARGOSS

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