[ncl-talk] can't seem to make my arrows bigger

[Kyle Griffin]

Hi Lesley,

I think you've switched your reference vector settings around. You should
be either making vcRefMagnitudeF *smaller* or making vcRefLengthF *larger*.
These act in concert to control the size of the vectors in your plot. Each
actually controls the magnitude and length of the vector in the reference
vector box in the bottom right of your attached image. You'll note that in
this current setting, you would need a wind speed of 2,000,000,000 m/s to
have a vector plotted at that size. In reality, you might want to set
vcRefMagnitudeF to a value somewhere between 10.0 and 50.0. If this still
doesn't make your vectors large enough, reduce the vcRefMagnitudeF to 1.0
and I'm sure you'll see some EP flux arrows appear. You can always check
the max() and min() of your vector field if you aren't sure the actual
magnitudes you are dealing with.

Let us know if you have any more questions.


Kyle

----------------------------------------
Kyle S. Griffin
Department of Atmospheric and Oceanic Sciences
University of Wisconsin - Madison
Room 1421
1225 W Dayton St, Madison, WI 53706
Email: ksgriffin2 at wisc.edu

On Fri, Apr 24, 2015 at 4:20 PM, Lesley Smith - NOAA Affiliate <
lesley.l.smith at noaa.gov> wrote:

> Hi gang,
> I'm using gsn_csm_pres_hgt_vector to make a plot.
> In the past it has worked great for me.
>
> This time, I can't seem to make my arrows big enough to see
> anything.  I attach a plot of contoured EP Divergence with the
> corresponding 2 EP components in vector form overlaid. The components are
> many orders of magnitude greater than the divergence.
> I've tried changing vcRefMagnitudeF and vcRefMagnitudeF to
> a variety of values and the arrows look the same.
> I tried scaling the vertical component (like one of the examples on the
> NCL website) to no effect.
>
> Eventually when I make vcRefMagnitudeF too small it suddenly gives the
> error:
>
> fatal:VectorPlotDraw: VVECTR - VECTOR NDC LENGTH TOO GREAT
>
> fatal:VectorPlotDraw: error drawing vectors
>
> fatal:VectorPlotDraw: draw error
>
> fatal:PlotManagerDraw: error in plot draw
>
> fatal:_NhlPlotManagerDraw: Draw error
>
>
>
> I'd love any suggestions!
>
> Thanks!
>
> -Lesley
>
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