Legend with two colors same as surface colors

Hello,

i wanted to change the rectangle of one color in the legend with the two colors of the surface.

Code:

---------------

close all;clear;clc;

% data

x = 0:1:10;

y = 0:1:20;

Z = sin(x') + cos(y);

% creates matrix with alternating ones and zeros

CData_0101 = zeros(length(x),length(y));

for r=1:size(CData_0101,1)

for c = 1:2:size(CData_0101,2)

CData_0101(r,c) = 1;

end

if mod(r,2)

CData_0101(r,:) = circshift(CData_0101(r,:),1);

end

end

surf(x,y,transpose(Z),transpose(CData_0101));

% legend should have the same two colors as surface. How?

legend;

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Afterwards i want the legend to look like this:

Has anyone a solution?

Thanks for replies!

Answer 1

[Gojo]

Hey Bernd,

For adding multiple colors in the legend, you would need to create annotations that mimics the behaviour you are aiming to achieve. Have a look at the following MATLAB Answer post suggesting a way to create legends with color gradients: https://www.mathworks.com/matlabcentral/answers/805881-how-can-i-gradient-the-legend-color-in-matlab

But if both the colors of the legend correspond to the same data, then for simplicity we can add multiple lines in the legend itself to map the color and the data it represents. For instance, I added dummy patches for adding the legend:

hold on;

% create patches for each color used in the surface plot
patch_y = patch(NaN, NaN, 'y'); % Yellow patch for legend
patch_b = patch(NaN, NaN, 'b'); % Blue patch for legend

% add custom legend
legend([patch_y, patch_b], {'data', 'data'});

I hope this was helpful!

[Bernd]

Thanks! The solution I was looking for was explained in the link provided and works quite well after few code adjustments.

[Gojo]

Glad to know the issue has been resolved!