Matlab 2016a - how to get xTickLabels on only some of the xTicks on an imagesc?

Question

I'm trying to create a 24x366 heatmap using imagesc with the x-axis labelled at 13 evenly spaced points as {'jan 15','feb 15',...,'dec 15','jan 16'}, and the y-axis labelled at every row from 1 to 24, like this:

Desired imagesc axes

When I run the script, it displays the y-axis as I want it, but it only displays the first label on the x axis and ignores the others. I can get this to work for a plot, but I can't get it to work for an imagesc. I've included my script below. Does anyone know how to make the imagesc display all 13 labels on the x-axis at evenly spaced intervals?

mylabels = {'jan 15','feb 15','mar 15','apr 15','may 15','jun 15','jul 15','aug 15','sep 15','oct 15','nov 15','dec 15','jan 16'};  
testspacing = (1:(60*24*30):528480);  
figure  
imagesc(rand(24,366))  
set(gca,'XTick',testspacing,'XTickLabel',mylabels,'XTickLabelRotation',45,'YTick',1:24,'YTickLabel',1:24)

E. Odj E. Odj · Accepted Answer · 2016-12-06T07:38:03

The problem with your code is that your only one of your ticks from testspacing falls in the range of the plot testspacing=[1 43201 ...]. You can check the range of your x-axis by running xlim without any arguments.

You can rescale testspacing to fit your x-axis e.g. like:

xmax = 366;
mylabels = {'jan 15','feb 15','mar 15','apr 15','may 15','jun 15','jul 15','aug 15','sep 15','oct 15','nov 15','dec 15','jan 16'};  
testspacing = (1:(60*24*30):528480);
testspacing = testspacing/max(testspacing)*xmax;  
figure  
imagesc(rand(24,xmax))  
set(gca,'XTick',testspacing,'XTickLabel',mylabels,'XTickLabelRotation',45,'YTick',1:24,'YTickLabel',1:24)

or you just generate testspacing properly. Since you are putting own labels on the axis anyway you might just choose use testspacing = [0:30.5:366] or testspacing = [0:30:366] depending on what you want. This will also help you debug your own code later on.

On another note you should think about reducing the number of labels in general and decide which of the labels are really helpful. Maybe every 2nd or 3rd month is enough. You can "remove" individual labels by setting them to empty strings ''.

Matlab 2016a - how to get xTickLabels on only some of the xTicks on an imagesc?

1 Answers