[Scilab-users] Needs help with surface plot & colormap

[Dang, Christophe]

Hello, 

De la part de surender_kumar
Envoyé : mardi 11 juin 2013 23:02

> I would like to do a
> colormap in such a way that the highest C value is most intense
> (say deep blue) while the lower values become more and more
> weaker..... finally the lowest C value having no color at all.

Well, the colormap is just a RGB matrix, the R, G and B components
ranging from 0 to 1.

So, deep blue is [0 0 1],
what is "colorless" for you?
White -> [1 1 1]
Black -> [0 0 0]

The *colormap (autumncolormap, coolcolormap, etc) instructions just
create matrices.

You can build your own colormap. The simplest way for you is to start
from a graycolormap, and force the last column to 1 for blue->white:

// **********

grayplot()

cmap = graycolormap(32);

cmap(:, 3) = 1;

xset("colormap", cmap)

// **********

or force the two first columns to 0 for blue->black

// **********

grayplot()

cmap = graycolormap(32);

cmap(:, 1:2) = 0;

xset("colormap", cmap)

// **********

"grayplot()" is just here to generate en example picture.

"32" is the number of levels, you can set any value.

Hope this helps

-- 
Christophe Dang Ngoc Chan
Mechanical calculation engineer
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