How to change default values and limits within a colormap

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Jose abel De la Fuente 2016-10-27

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https://ww2.mathworks.cn/matlabcentral/answers/309391-how-to-change-default-values-and-limits-within-a-colormap

评论： Image Analyst 2016-10-29

Hi, How are you?.

I want to change the default values in a colormap, In order to plot a map of "diopter powers", like in this image:

However each value is related with a value (or a range of values). For example: if a "diopter power" has a value 39 to 40, the color has to be green. (It is a standard).

Someone could help to know, how I can choose the default values to each color in the colormap.

Thanks for your help.

Rewards.

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Answer 1

Image Analyst 2016-10-27

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https://ww2.mathworks.cn/matlabcentral/answers/309391-how-to-change-default-values-and-limits-within-a-colormap#answer_240926

在 MATLAB Online 中打开

Looks kind of like jet upside down. Try this

imshow(grayImage, []);
myColorMap = flipud(jet(256));
% Top row black
myColorMap(end, :) = 0;
% Bottom row white
myColorMap(1, :) = 1;
colormap(myColorMap);
colorbar;

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Jose abel De la Fuente 2016-10-28

编辑：Jose abel De la Fuente 2016-10-28

在 MATLAB Online 中打开

It is a grean idea!!

However I have tried to do it of different way (I know that is not the best idea), but It was the only way to solve my problem, like in this link:

http://stackoverflow.com/questions/11286539/matlab-surf-with-different-colour-schemes

This is my code:

supDiop = Dioptrica surface power; supAlt = surface height; pxEval = x axis; pyEval = y axis;

Each value of subAlt will be associated a color value which is related with the subDio.

   surfc(pxEval,pyEval,(1./(supDiop>=1 & supDiop<=9)).*supAlt,'facecolor',[0/256,1/256,48/256]);
        surfc(pxEval,pyEval,(1./(supDiop>=9 & supDiop<=14)).*supAlt,'facecolor', [0/256,0/256,82/256]);
        surfc(pxEval,pyEval,(1./(supDiop>=14 & supDiop<19)).*supAlt,'facecolor', [0/256,0/256,115/256]);
        surfc(pxEval,pyEval,(1./(supDiop>=19 & supDiop<24)).*supAlt,'facecolor', [0/256,0/256,163/256]);
        surfc(pxEval,pyEval,(1./(supDiop>=24 & supDiop<29)).*supAlt,'facecolor', [0/256,0/256,198/256]);
        surfc(pxEval,pyEval,(1./(supDiop>=29 & supDiop<35.5)).*supAlt,'facecolor', [0/256,0/256,254/256]);

Everything seemed fine, but I found other problem. when I coupled the surf one after the other (with hold on command) the images in the suft appear with omitted points like in this imagen:

can someone help me to know the cause?... and the solution.