Is there a way to insert a common ylabel to secondary axes in a tiled layout?

Hi everyone,

Dabbling a bit in MATLAB for the past year, mostly for data analysis. I am currently using version 2020 a and recently started enjoying the tiledlayout functionality. I was wondering, if there is a way to insert a shared y-axis title for secondary y-axes? For example, in this code:

t = tiledlayout(2,2);
for i = 1:4
    f = figure(1);
    ax = nexttile;
    yyaxis left
    x = (1:10);
    y = rand(1,10)*100;
    plot(x,y)
    yyaxis right
    plot(x,sin(y))
end
xlabel(t,'X')
ylabel(t,'Y')

I would like to insert a ylabel for the right axes (lets say 'Y2') that is 'shared' just as 'Y' is for the left axes. I haven't found a solution that worked for me yet, all information I could find would either relate to tiled layouts or two y axes, I haven't found something that combines the two.

I hope you understand my problem, any help is highly appreciated.

Answer 1

[Rishik Ramena]

You need not create a figure for each of your tile, instead you can have a common figure which can then later be labelled as shown.

close all;

fig = figure;
t = tiledlayout(2,2);
for i = 1:4
    nexttile;
    yyaxis left
    x = (1:10);
    y = rand(1,10)*100;
    plot(x,y)
    yyaxis right
    plot(x,sin(y))
end

ax = axes(fig);
han = gca;
han.Visible = 'off';

% X label
xlabel('X')
han.XLabel.Visible = 'on';

% Left label
yyaxis(ax, 'left');
ylabel('Y1')
han.YLabel.Visible = 'on';

% Right label
yyaxis(ax, 'right');
ylabel('Y2')
han.YLabel.Visible = 'on';

[Manuel Bruch]

Thank you very much! This definitely does the trick. The left y-label was in my case overlapping with the axes of the plots next to it but by changing the label position that is no issue.

[Shahrose Khan]

didn't work

Answer 2

[Andrei Alexandru Duma]

I had a much more complex figure and with the answer from Rishik I could not get the axes to properly align to the right and to not get overlayed on top of the ytick labels. Here's my minimal implementation which adds a new axes object to the figure:

% reset(groot)
close all;
fig = figure;
t = tiledlayout(2,2);

for i = 1:4
    nexttile;
    yyaxis left
    x = (1:10);
    y = rand(1,10)*100;
    plot(x,y)
    yyaxis right
    plot(x,sin(y))
end

h = xlabel(t, 'XAXIS LABEL');
% get font style of left axes
axl = h;
ylabel(t, 'YAXIS LABEL (LEFT)')

axr = axes(t.Parent); % same parent as tiledlayout
% match the new axes position [left bottom width height] to tiledlayout
axr.Position = t.Position; 
% compress width of tiledLayout to fit the right axes
t.Position(3) = t.Position(3) - 0.05; 
% make new axes invisible
axr.Color = 'none';        % transparent background
axr.XTick = [];
axr.YTick = [];
axr.XColor = 'none';
axr.YColor = 'none';
axr.YAxisLocation = 'right';

ylabel(axr, 'YAXIS LABEL (RIGHT)', 'Color', 'k');

Answer 3

[Matt J]

t = tiledlayout(2,2);
for i = 1:4
    f = figure(1);
    ax = nexttile;
    yyaxis left
    x = (1:10);
    y = rand(1,10)*100;
    plot(x,y)
    yyaxis right
    plot(x,sin(y))
end

addYLabels(t, 'Y1','Y2');

function axOverlay = addYLabels(t, leftLabel, rightLabel)

    % Create invisible axes
    axOverlay= axes(t.Parent);
    t.OuterPosition=axOverlay.Position;
    axOverlay.Color = 'none';
     
    pos=["left","right"];
    labels={leftLabel, rightLabel};

    for i=1:2
    % Put ylabel on the right
    yyaxis(axOverlay,pos(i))
    axOverlay.XColor='none';
    axOverlay.YColor='none';
    axOverlay.XTick = [];
    axOverlay.YTick = [];
    ylabel(axOverlay,labels{i},'Color','k');
    end


end