[ncl-talk] Changing a color in a color table to transparent

[Ty Buckingham]

Hi there,

Is it possible to change a single color in an already constructed color map to transparent?

As an example: I wish to use the "hotcold_18lev" color table, but wish to change the white to transparent. I do not have editing permission to the NCARG root hence cannot change the RGBA value directly. Is it possible to change it within the NCL script?

Initially, I tried this:


cmap                = read_colormap_file("hotcold_18lev")

cmap(10:11,)        = 0.0                ; makes whites transparent

res at cnFillColors    = cmap


Yet received the error:


fatal:Error in subscript, normal subscripting is being used, make sure named subscripting has not been used


which is related to the "cmap(10:11,)" line.


Thanks in advance!

Ty
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