>I have looked and I bet it is out there but I cannot find a straightforward
>way when filling in a contour to have a color represent a specific value
>range even when the low and high end ranges are not always in the grid.
>
>I have a 2d grid of Relative Humidity and I want to color certain value
>ranges specific colors. This automatically falls into place when I have a
>full range of 0 - 100 but if the min value of the RH is say 40% then I still
>get the colors associated with 0-40% in the plot. The same is true at the
>upper end.
>
>For example I want:
>0-10% red
>10-40% yellow
>40-60% light green
>60-80% green
>80-100% blue
>
>If there is no RH below 40% then I don't want the red and yellow in the
>plot. If there is no RH above 80 then I don't want the max value to be blue
>
>Any ideas. I have thought about getting the max and min values in the grid
>and then trying to use SpreadColorEnd and SpreadColorStart but this seems a
>bit more complicated then I would think is needed and I have tried playing
>with the nglSpreadColors command and I did not get the results I expected.
>Also I would think it would have repercussions on the other colors in the
>plot.
-----
I am not a pyngl user but via NCL
[1] pick a color map [or make up your own]
http://ngwww.ucar.edu/ncl/coltable.html
[2] Use "ManualLevels"
[3] Select colors from color map for specific intervals
wks = gsn_open_wks ("ps", "demo" ) ; open workstation
gsn_define_colormap(wks1,"BlAqGrYeOrReVi200")
res = True ; plot mods desired
res_at_cnFillOn = True ; turn on color fill
res_at_cnLevelSelectionMode = "ManualLevels"
res_at_cnMinLevelValF = -0.7 ; plot to match Curtis data
res_at_cnMaxLevelValF = 0.7
res_at_cnLevelSpacingF = 0.2
res_at_cnFillColors = (/ 8,32,60,90, 0,120,143,164,190/) ; BlAqGrYeOrReVi200
The above gives:
[8] [32] [60] [90] [0] [120] [143] [164] [190] => colors
---------------------------------------------------------
| | | | | | | | | |
---------------------------------------------------------
-0.7 -0.5 -0.3 -0.1 0.1 0.3 0.5 0.7
A sample .gif of this is at:
http://www.cgd.ucar.edu/web/public_html/shea/y.TP_CAM_cor_AllMonths.gif
---- There are other ways to do this but I had this handy. The following is NCL but a pyngl script can ve created by analogy. see: http://www.cgd.ucar.edu/csm/support/CSM_Graphics/color.shtml Regards _______________________________________________ pyngl-talk mailing list pyngl-talk_at_ucar.edu http://mailman.ucar.edu/mailman/listinfo/pyngl-talkReceived on Thu Feb 24 2005 - 14:19:49 MST
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