subplot aligment automatic method

Hi,

I would like to know if there is an easy way to align subplots ina figure. Here is my problem.

I have a figure with a subplot with a colorbar (on the right of the plot) and a subplot without a colorbar but with two y axis and relative labels bennith it. I would like the plot to be aligned (meaning the x values of the two subplot should be at the same horizontal location). The only way I found to achive that is to thinker with the 'Position' options of the subplot. Like:

subplot(4,2,6,'Position', [0.095 0.1 0.81 0.1428])

But thsi solution depends on the size of the figure itself and on the screen the figure is beign plotted to (at least that is my guess since I get different results dependig on the screen matlab is plotting it in and if I maximize the figure or not).

minimal working example of the problem:

C = [0 2 4 6; 8 10 12 14; 16 18 20 22];
figure
subplot(2,1,1)
imagesc(C)
colorbar
subplot(2,1,2)
hold on
yyaxis left
plot(C(:)); ylabel('C')
yyaxis right
plot(-C(:)); ylabel('-C')

Real case problem output

Any advice is appriciated!

[Mathieu NOE]

plot - Matlab: How to align the axes of subplots when one of them contains a colorbar? - Stack Overflow

[giacomo labbri]

thanks but his does not work (unless I am doing something wrong).

here is what I have tried:

C = [0 2 4 6; 8 10 12 14; 16 18 20 22];
figure
h1=subplot(2,1,1);
imagesc(C)
colorbar
h2=subplot(2,1,2);
%hold on
%yyaxis left
plot(C(:)); ylabel('C')
% yyaxis right
% plot(-C(:)); ylabel('-C')
linkaxes([h1,h2],'x')

pos1=get(h1,'Position');
pos2=get(h2,'Position');
pos2(3)=pos1(3);
set(h2,'Position',pos2);

running this code result in an unchanged situation (the figure are not aligned). I have noticed that the position vectors (pos1 and pos2) are equal except for the y-postion element (even without changing the position vectors). Maybe the axis include the colorbar somehow? I didn't say I am using Matlab 2020b. Maybe it is relevant.

I have found out that tiledlayout is an alternative to subplot and the "tiles" are all aligned. Still I would like to understand why this is not working.

[Adam Danz]

> I would like to understand why this is not working

It does work in the sense of equating axis sizes. It's similar to method 1 in my answer. The problem is the linkaxes line which changes the xlim property which has nothing to do with axis position within the figure.

[giacomo labbri]

Just for the record even commenting the linkaxes line I still get the same result. But your answer (see below) do work, so thanks!

Answer 1

[Adam Danz]

Method 1: equate axis sizes for all axes after adding colorbar

Size of axes without a colorbar will be set to the size of axes with a colorbar.

% Create Demo
ax = gobjects(2,3); 
for i = 1:5
    ax(i) = subplot(3,2,i);
    imagesc(ax(i),rand(100,1000))
    colorbar(ax(i))
end
ax(end) = subplot(3,2,6);
plot(ax(end), 1:1000,(1:1000).*rand(1,1000)*2)

% Set the width and height of all axes to the min width & height
allAxPos = vertcat(ax.Position);
allAxPos(:,3:4) = min(allAxPos(:,3:4)).*ones(numel(ax),1);
set(ax,{'position'},mat2cell(allAxPos,ones(numel(ax),1),4))

Method 2: Restore axis position and set colobar positions

The axes maintain their original sizes prior to adding colorbar. The colorbar position and width is adjusted.

function addOutsideColorbar(ax)
pos = ax.Position; 
cb = colorbar(ax,'EastOutside'); 
ax.Position = pos; 
cb.Position(1) = sum(ax.Position([1,3]))+.01;
cb.Position(3) = cb.Position(3).*.5;
end

Demo

ax = gobjects(2,3); 
for i = 1:5
    ax(i) = subplot(3,2,i);
    imagesc(ax(i),rand(100,1000))
    addOutsideColorbar(ax(i))
end
ax(end) = subplot(3,2,6);
plot(ax(end), 1:1000,(1:1000).*rand(1,1000)*2)

Method 3: Use tiledlayout

ax = gobjects(2,3); 
tlo = tiledlayout(3,2);
for i = 1:5
    ax(i) = nexttile(tlo);
    imagesc(ax(i),rand(100,1000))
	colorbar(ax(i))
end
ax(end) = nexttile(tlo);
plot(ax(end), 1:1000,(1:1000).*rand(1,1000)*2)

[giacomo labbri]

thanks for the detailed aswers!