[ncl-talk] Small issue plotting highways

[Rick Brownrigg]

Hi Andrew,

It's odd that you are getting inconsistent results. Do you see the same
thing if you write to a PS or PDF file? I don't know what's going on, but
it looks like a  bit of overzealous anti-aliasing. There's a resource to
control whether antialiasing is applied or not:

https://www.ncl.ucar.edu/Document/Graphics/Resources/wk.shtml

It's on by default and generally yields better results, but you might
experiment with it.

Wish I had a better answer.
Rick


On Tue, Jun 22, 2021 at 8:45 AM Andrew Kren - NOAA Federal via ncl-talk <
ncl-talk at mailman.ucar.edu> wrote:

> Hi there,
>
> I am plotting radar data and overlaying highways onto the map. I first
> plot the radar analysis, then overlay the highway information by
> reading/plotting the shapefile.
>
> At times, when I view the PNGs, the highways show up as blotched out (lack
> of detail and pixelated; see attached image). At other times, the highways
> show up very clear and darker as expected. Is there a reason for this?
> Below shows a snippet of my code that produces the radar plot and the
> highway overlay.
>
>  plot = gsn_csm_contour_map(wks,radar,res)
>
>  ; add highway polylines to the map from shapefile
>  plres = True
>  plres at gsLineColor = "grey48"
>  plres at gsLineThicknessF = 0.2
>  id =
> gsn_add_shapefile_polylines(wks,plot,SHAPE_DIR+"roadtrl020.shp",plres)
>
> Thanks,
>
> --
>
> Andrew Kren
> Meteorologist
> NOAA's National Weather Service
> Raleigh Forecast Office
> 1005 Capability Drive, Suite 300
> Raleigh, North Carolina 27606
> voice: 919-326-1035
> mailto: andrew.kren at noaa.govhttp://www.weather.gov/rah
>
>
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