How to plot this colormap correctly?

I am trying to plot a heat map of temperature along depth and time. However the plot does not match the provided data. For instance at z = -8612 m I have T = 80.57°C, but it would be something near 165°C.

I attached my .mat files, the depth, time and temperature data. My code to plot is:

% Plotting
figure;
imagesc(time, depth, temp);
colormap('jet');
colorbar;
xlabel('Time');
ylabel('Depth');
title('Temperature Heat Map');
set(gca, 'YDir', 'normal');

Could someone please give me any idea of what is happening here?

Thanks!

Answer 1

[Voss]

The difference between adjacent elements of depths is not constant. (Same for time.)

load depth
load temp
load time

% difference between adjacent elements of depths:
disp(diff(depths.'))

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An image uses equally-sized pixels, so it's not an appropriate choice to represent data like this where the x- and y- spacing is not constant.

Better is to use a surface:

surface(time, depths, temperature, 'EdgeColor', 'none')
xlim(time([1 end]))
ylim(depths([end 1]))
colormap('jet');
colorbar;
xlabel('Time');
ylabel('Depth');
title('Temperature Heat Map');
set(gca, 'YDir', 'normal');

[Williams]

Perfect!! Many thanks for the solution!!

[Voss]

You're welcome!