Problem plotting with imagesc

Hi there,

I'de like to create a 2D plot with a 3rd dimension in colorscale exactly like 'imagesc' does but with a controlable y scale. When using imagesc(X,Y,Z) it sets the Y scale linear between the two ends of the Y vector ignoring everything in between.

Is there a way to do so? maybe by modifying the 'imagesc' function itself or perhaps by another function?

p.s I know that function such as 'pcolor' allows such scaling but it does not plot the same output as i require (and imagesc gives).

Thanks in advance

Y

Answer 1

[Mathieu NOE]

hello

this is the way I control the Z scale rendering of imagesc :

A = rand(100,100);
figure(1);imagesc(A);colorbar('vert');

% let's say we don't want to display values below "lower_limit" and above "upper_limit"
lower_limit = 0.75;
upper_limit = 0.9;
A(A<lower_limit) = lower_limit; % or NaN
A(A>upper_limit) = upper_limit; % or NaN
figure(2);imagesc(A);colorbar('vert');

[Yonatan Gershuni]

Thank you for your answer. However my problem is not setting upper or lower limits on an axis but rather setting a costume bar. I.e say you have a y vector with values y=[1, 1.1, 1.2, 1.3, 5] (with matching x vector and z matrix). If you use imagesc(x,y,z) you will see the y axis on your image will be from 1 to 5 but in even increments.

[Mathieu NOE]

ok , so you would like imagesc to be displayed with uneven "pixels" to match the uneven spacing of x and y ?

[Yonatan Gershuni]

Exactly, only im not sold on imagesc so any function would do just fine if it could do it

[Mathieu NOE]

Would suggest you look here :

https://fr.mathworks.com/matlabcentral/fileexchange/11368-uimage-uimagesc

https://stackoverflow.com/questions/13977859/non-uniform-axis-of-imagesc-in-matlab

I believe this should solve your problem

[Yonatan Gershuni]

It works! Thank you very much!