Re: shaded colors over a gray filled continent

From: Andries De Vries <a.devries_at_nyahnyahspammersnyahnyah>
Date: Fri May 17 2013 - 02:45:21 MDT

Dear All,

In addition to the previous email, I send attached the NCL script that was used. Note that I did not send the script as for the plots sent previously (the corresponding data files are way too big and too many to upload them properly), but for a similar plot, see the attachment. The idea is the same. The plot shows precipitation from era-interim (left side) and aphrodite (right side). Now I want for the Era-interim data (left hand side) fo fill in the continent or sea surface with a light gray color to show a contrast between the continents and sea for better visibility of the topography, without disturbing the precipitation colors.

The Aphrodite plot (right hand side) shows missing values in black; I did not need to add this color to the color table, since it is already included. However, when I would like to change the black color of missing values into light gray, I have to add this color to the color table (I use NCL version 6.0.0). I could do the same for the Era-Interim plot, via adding a gray color to the color table for values of e.g. -2 to -1, and then to change the precipitation values over continents or sea surface with "0" precipitation values to -1, so the continent or sea will be filled gray where there is no precipitation.

My question is if there is a more easy way to fill in continent or sea surface with gray, while the precipitation colors appear always on top (as dominant color). And if the above described solution is the only one, how should I remove again the added gray color from the color table in the final plot (I dont want to show the gray color in the color table for negative precipitation values).

The names of the script, the plot, and the data in the map "incoming" are as follows:
- precipitation_ERA-Int_APHRO_daily_PANEL_ncl-talk.ncl (also attached)
- PRECIP_ERA-Int_Aphro_daily_CT2_ncl-talk_1987-10-15_to_18.pdf (also attached)
- ei_fc_totprec_gg128_step12_198710.grib

Thanks a lot in advance!


From: Andries De Vries []
Sent: Thu, 16 May 2013 19:33:22 +0200
Subject: shaded colors over a gray filled continent

      Dear NCL users,

I use NCL (version 6.0.0) to make a panel plot that shows precipitation (colors) and geopotential height contours at 1000 (solid lines) and 500 hPa (dashed lines). See attached plot1. This figure is very busy and it may be difficult for the reader to recognize the region with respect to the topography. One way to make this plot more clear might be to fill the continent or sea surface with a light gray color, but without dominating the precipitation. So far I have not seen an example on the NCL UCAR website that shows both shaded colors over a gray filled continent/sea. What would be the most easy solution for this?

I have one potential idea. Previously I made a similar plot (see attached plot 2) with missing values in gray shaded colors. For this I had to add in a complicated way a gray color to the color table. In a similar way I could add a gray color to the color table in plot1 for values from e.g. -2 to 0; and to change precipitation values of "0" over land or sea to e.g. -1. As such the land or sea surface without precipitation will be filled gray. However, I do not want the gray color to be included in the color table. How should I remove one color from the final color table without losing the color in the plot?

Thank you very much for any helpful suggestion!


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Received on Fri May 17 02:45:34 2013

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