How to add top and bottom x-axes labels to a heatmap?

I have a heatmap to which I want to add two x-axes, top and bottom, representing two different quantities. Attached are the .fig I got, and the source .mat.

Answer 1

[Benjamin Kraus]

If you check out this other question on MATLAB Answers: https://www.mathworks.com/matlabcentral/answers/378670-move-x-axis-labels-on-a-heatmap-to-the-top

My answer from November 8, 2023 shows how to leverage tiledlayout to create an axes that sits under the heatmap and can be used to add additional labels. This same technique can be used to add duplicate labels on the top and bottom of the heatmap. It has working example code you can start with.

Answer 2

[Guilherme]

Hi @ct8! I think you may want to have a look on this page: https://www.mathworks.com/help/matlab/creating_plots/graph-with-multiple-x-axes-and-y-axes.html#mw_ca4bd216-f46d-49cd-94ed-3fe176088b04

It shows how to add two axes to a single plot. Then, you'd need to use xlabel and reference the Xaxis that you want to change as the target. You'd need something like that:

t = tiledlayout(1,1);
target_bottom = axes(t);

%% 
% Plot Bottom
%%
target_top = axes(t);
target_top.XAxisLocation = 'top';
%%
% Plot Top
%%

xlabel(target_bottom,'Bottom Axis')
xlabel(target_top,'Top Axis')

[ct8]

I have tried this, but it is not working for my heat map. Essentially I want to know how to define the titled layout in my code which generates a heatmap.

figure()
imagesc(x,z,y')
% reproduce heatmap's colormap
n=256;
cmap = [linspace(.9,0,n)', linspace(.9447,.447,n)', linspace(.9741,.741,n)'];
colormap(cmap); 
axis xy
colorbar()