Generate an N-color colormap using an existing colormap

From: John Kerfoot <johnkerfoot_at_nyahnyahspammersnyahnyah>
Date: Fri Feb 01 2013 - 12:30:58 MST


I'd like to scatter some polymarkers over a map and color-code the markers
based on their values. Ideally, I'd like to read in an existing colormap
using the read_colormap_file NCL function and then linearly interpolate
through each of the RGB arrays to create a new colormap with an arbitrary
number of levels (corresponding to the bins I set up using the data).

For example, let's say I have some data and want to color code the values
as a percentage where my percentage bins are:

0 - 9%
10 - 19%
20 - 29%
30 - 39%
40 - 49%
50 - 59%
60 - 69%
70 - 79%
80 - 89%
>= 90%

That's 10 levels.

If I read in an exising NCL colormap, say helix, which has 256 colors, I'd
like to interpolate through each of the RGB channels and end up with 10
colors that I can use to color my markers depending on which bin they fall

How would I go about achieving this, keeping in mind that my number of
levels will change with the dataset I'm plotting?


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Received on Fri Feb 1 12:31:10 2013

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