MATLAB Answers

Delete axis, keep legend

Latest activity Edited by Adam Danz
on 6 Aug 2019
I need to have a subplot with an empty axis, but with a legend. My workaround to put a title on an empty subplot was:
if isempty(data) % Failsafe for empty section
pie(1); % Plots any pie chart
title(data_title);
cla; % Clears axis
end
But it does not work for the legend, it vanishes with it.
How can I deal with it?

  1 Comment

So, I have this figure with 6 subplots. The legend for the 3 upper and the 3 lower are the same, so it appears only in the rightmost subplots. However, sometimes the rightmost plot can be like the upper left for this sample (an empty plot created with cla()). I need to make it so that the legend appears with all 3 entries even for cases like this.
For reasons of confidenciality, the titles and legend entries must be censored

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1 Answer

Adam Danz
Answer by Adam Danz
on 5 Aug 2019
Edited by Adam Danz
on 6 Aug 2019
 Accepted Answer

To create a legend without any visible data using plot().
plot(nan, 'r-', 'DisplayName', 'MyLegendName');
legend();
Note: cla() will still clear the legend but you won't need to call cla() because nothing is plotted.
To create a legend without any visible data using pie()
% Create a dummy pie chart and its legend
h = pie([1,1,1]);
lh = legend('a','b','c')
% Delete non-patch objects
hPatch = h(strcmp(get(h,'type'),'patch'));
hNotPatch = h(~strcmp(get(h,'type'),'patch'));
delete(hNotPatch)
% Remove Faces of patches
set(hPatch,'Faces', NaN)

  2 Comments

Hey, Adam!
I tried your suggestion, but it does not work exactly as I need, I believe the command has to be necessarily pie(), and that it should plot something with exaclty 3 sectors.
Please refer to my comment on the question, I believe it clarifies what I'm after :)
Adam Danz
on 6 Aug 2019
I updated my answer to show how this is done with pie charts.
First you must create a pie chart and its legend. Then you must remove the text and then remove the faces of each patch by replacing their values with NaN. That makes the entire pie chart go away and retains the legend.

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