How to change colorbar's color (in some particular value interval)?

Hi , I want to change colorbar's color in some particular value interval.

For example , I likes the jet colorbar , link is my figure, but I want to

let the value between -0.5~ 0.5 to become white color, how can I do this?

thank you much !!

https://docs.google.com/file/d/0BxUY6-ywKIvpZjlqRnFSX0JYMUU/edit?usp=sharing

Answer 1

[Walter Roberson]

You need to create a new colormap that has the appropriate colors in the appropriate range.

It appears that you have your plot set up to automatically map your minimum data to the lowest color, and your maximum data to the highest color.

I estimate that the range you want to change is roughly 2/3 of the way to the highest color as your range looks like -4 to +2 .

So you need to use something like

newmap = jet;                    %starting map
ncol = size(newmap,1);           %how big is it?
zpos = 1 + floor(2/3 * ncol);    %2/3 of way through
newmap(zpos,:) = [1 1 1];        %set that position to white
colormap(newmap);                %activate it

[chia hua]

Thanks a lot , it work!!

But is there any way to know the correspond value to each color in the colorbar?

Because I have many figure to plot, each have different scale, if I can find

out the value to color correspondence relationship , I can write a program

to automatic change color around zero value.

thank you!!!

[Walter Roberson]

newmap = jet();       %change as desired, e.g., flag(256)

minz = double(min(YourZ(:)));
if minz > 0
  disp('Your range is all above 0, no change');
else
  maxz = double(max(YourZ(:)));
  if maxz < 0
    disp('Your range is all below 0, no change');
  else
    ncol = size(newmap, 1);
    zratio = (0 - minz) ./ (maxz - minz);
    zpos = max( round(zratio * ncol), 1);  %closest non-zero
    newmap(zpos,:) = [1 1 1];   %set there to white
    colormap(newmap);           %activate it
  end
end

[chia hua]

thank you!!!!

Answer 2

[Amith Kamath]

You can manually change the colormap, using COLORMAPEDITOR:

http://www.mathworks.com/help/matlab/ref/colormapeditor.html

Double click on the color markers below the spectrum displayed, and choose the color you want to display that range of data in, using the color picker.

Answer 3

[Makarand]

google Recolor_pcolor