[ncl-talk] Fwd: Pennants wind barbs thickness

David Brown dbrown at ucar.edu
Thu Jul 24 12:11:34 MDT 2014


Hi Rabah,
As you know I previously answered this question for you personally prior to
your joining ncl-talk. For the record I am now answering on ncl-talk:

You have diagnosed the problem correctly, and unfortunately there is no
resource to directly control the size of the pennant part of the wind barb
glyphs. The size and area of the pennants is fully determined by
the vcWindBarbTickLengthF and the vcWindBarbTickAngleF. Unfortunately there
is currently no adjustment made to account for the width of the lines,
which also has the effect of making the barbs longer than their nominal
length. No one has ever asked for this kind of flexibility in the past, but
I can see that it could be useful.

You could try playing with the tick length and tick angle resources. They
may help give you a combination that looks better. But until we can add
another option, my suggestion would be to just try to keep the width as
small as feasible for your purposes.
 -dave



On Tue, Jul 22, 2014 at 4:54 PM, Rabah Hachelaf <hachelaf at sca.uqam.ca>
wrote:

> Hi NCL users,
>
> I have problem with plotting wind barb with a relatively big thickness
>
> I am using vcWindBarbLineThicknessF command to increase wind barb
> thickness
> it's correct for all wind barbs only for higher than 50KT ones where the
> pennants or small triangle aren't affected by the thickness set.
> When reading some documentation i noted that
>
>   " The pennants are drawn using a filled polygon, while the ticks, the
> shaft, and the calm circle are all rendered with polylines."
>
> So i think this is why pennants aren't affected by the thickness change.
>
> Have you some tricks to solve this problem and get the same pennants
> thickness like the ticks.
>
> Attached you can find an example of my case, where wind speed is supposed
> to be about between 55KT and 60KT
>
> Thank you.
>
> ------------------------------
> Cordialement,
> Best regards,
> Rabah Hachelaf
> Msc Studient UQAM
> Montréal/CANADA
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