Re: Plotting Colors for Missing Values

From: Adam Phillips <asphilli_at_nyahnyahspammersnyahnyah>
Date: Wed, 06 May 2009 08:55:03 -0600

Hi Melissa,
As far as I know, nothing has changed with regards to filling of missing
value areas, or of filling of land areas between 5.0.0 and 5.1.0.

Note that when you are specifying a color in any resource that accepts
it, that NCL will use the color you specify, or if that exact color
isn't available, it will try to pick the color that it thinks is closest
to the color your asked for.

For instance, let's say that while setting cnFillOn = True (needed to
use cnMissingValFillColor), I set cnMissingValFillColor = "white". If my
colormap does not have white in it, NCL will choose a color it thinks is
closest to white, say perhaps light green.

If what I said above doesn't help, respond to the group with your
resource list along with a .jpg,.gif, etc. of your plot.

Melissa A Richards wrote:
> Hello,
> I am using "gsn_csm_contour_map" to plot various variables at
> different pressure height levels. When I plot data for the 850hPa
> level, I have a large area of missing values (due to mountainous
> terrain). When I ran my script on NCL 5.0.0 the plot showed the
> missing values correctly, by plotting the background white with the
> continent outlines and lat/lon gridlines plotted in black. When I run
> the same exact script on NCL 5.1.0, the missing values are filled with
> a blue/gray color. Was there something changed between NCL 5.0.0 and
> NCL 5.1.0 that would effect this? I checked the release notes and did
> not see anything.
> A few other notes...
> It seems that in 5.1.0 it chooses a color from the color table to fill
> in the missing values with (the blue/gray color is part of my color
> table). I attempted to use res_at_cnMissingValFillColor set to "white"
> and the missing values were still plotted with the blue/gray color. I
> attempted to run the same plot using a standard NCL color table. The
> missing values were plotted correctly when I used the "rainbow" color
> table. When I used the "testcmap" color table, it plotted the missing
> values with a light green color. It seems that I am having trouble
> with the missing values if a color table contains "white" within the
> color table. Am I missing something?
> Thanks!
> Melissa
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Adam Phillips			   
National Center for Atmospheric Research   tel: (303) 497-1726
ESSL/CGD/CAS                               fax: (303) 497-1333
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Received on Wed May 06 2009 - 08:55:03 MDT

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