Re: Graphics issue with vcGlyphStyle = "LineArrow"

From: David Brown <dbrown_at_nyahnyahspammersnyahnyah>
Date: Thu Jul 12 2012 - 18:40:19 MDT

Hi Kyle,

First of all, just FYI, the glyph style you are using in this plot is "FillArrow" not "LineArrow". At first your description of this bug sounded totally weird, but after looking around a bit, I did in fact discover a forgotten (by me) interdependence between the wind barb glyph style and the fill arrow glyph style. They share a small bit of memory used to parameterize their basic shape and style. So it looks like I introduced this bug when implementing the automatic handling of the Northern/Southern hemisphere compensation for wind barbs (coincidentally at your urging it turns out).

Anyway I have made what I think is a simple fix, although I have to say that the glitches I get look a bit different from yours, and therefore I am not totally sure it is completely fixed without having access to your script and data. If you would like to test it out, let us know and we can get you a new version to try.
 -dave

On Jul 12, 2012, at 2:19 PM, Kyle Griffin wrote:

> Hi all...
>
> In NCL 6.1.0-beta, there seems to be an issue with vector glyph styles plotted as LineArrows. Specifically, wind barbs are plotted in the arrow head when the magnitude of the vector is of sufficient magnitude. A sufficient magnitude seems to be in excess of 10 m/s, which is the approximate threshold where a full barb would start being plotted on wind barbs. Barbs are only plotted in the left-right plane, regardless of the direction of the actual arrow. Finally, the barbs only seem to appear with LineArrows that are oriented in a direction such that their meridional component exceeds their zonal component. I have attempted to edit these apparent wind barbs, but the vcWindBarb resources have not had any impact on thickness, length, spacing, or tilt that I have seen.
>
> I have attached an example here, with reference vector with which you can estimate the magnitude (arrows below 4 m/s are not plotted).
>
> The bug is not present in 6.0.0 with an identical script. I haven't attached a sample script or data because this seems to occur regardless of the script commands or data used to make the plot. I can shrink and clean up my script in order to provide a sample, if necessary.
>
> Thanks for looking at this!
>
>
> Kyle
> -----------------------------------------------------
> Kyle S. Griffin
> Dept. of Atmospheric and Environmental Sciences
> University at Albany, SUNY
> 1400 Washington Ave, Albany, NY 12222
> Office: ES-218 Email: kgriffin@albany.edu
> http://www.atmos.albany.edu/student/kgriffin/
>
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Received on Thu Jul 12 18:40:29 2012

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