stock plots, errorbars in a growing variable.

Hello,

I find a little bit difficult to understand how to propperly handle multiple figures in matlab.

I am creating different plots (set of points (of vector values) and errorbars) that are created inside a loop and stacking them together as the loop is runned (using hold on).something like this:

for i=1:5

for j=1:2

figure (1)

plot(a{i}{j}(:,1),b{i}{j}(:,1))

errorbars(a{i}{j}(:,1),b{i}{j}(:,1),Uuper{i}{j}(:,1),Ulower{i}{j}(:,1))

figure(2)

plot(a{i}{j}(:,1),c{i}{j}(:,1))

errorbars(a{i}{j}(:,1),c{i}{j}(:,1),Uuperc{i}{j}(:,1),Ulowerc{i}{j}(:,1))

end

end

and wanted to create a subplot of the combination of them. I know that I can use the subplot directly inside of the loop to stack them directly. but what I was wondering is to be able to define the figures as a "single" figure and then calling it back to use the tiledlayout .Something like stacking them inside a variable array that could be called as fig(1) , fig(2) etc.

thanks

Answer 1

[Benjamin Kraus]

I'm not sure I completely follow your question, but I think you are asking about using handles to graphics objects. For example, when you call figure, instead of passing in "1" or "2" (which is the figure numeric identifier), you can just call the figure command and store the output. Similarly, you can call the axes or nexttile commands to create axes, and then store the output to use as a handle to the axes. This will let you add new things to existing axes. Then, when you call plot or errorbar, provide the axes handle as the first input so the command knows which axes to use when plotting.

Here is a code example:

f1 = figure; % Create a new figure.
ax1 = axes(f1); % Create an axes in the first figure.
hold(ax1, 'on');
f2 = figure; % Create a new figure.
ax2 = axes(f2); % Create an axes in the second figure.
hold(ax2, 'on');

for i=1:5
  for j=1:2
      plot(ax1, (i+j):(i+j+4), j:(j+4))
      errorbar(ax1, (i+j+1):(i+j+5), j:(j+4))
      plot(ax2, (i+j):(i+j+4), j:(j+4))
      errorbar(ax2, (i+j+1):(i+j+5), j:(j+4))
   end
end

If you want the two axes in a single figure, I recommend using nexttile to create the axes:

f = figure; % Create a new figure.
t = tiledlayout('flow');
ax1 = nexttile(t); 
ax2 = nexttile(t);
hold(ax1, 'on');
hold(ax2, 'on');

for i=1:5
  for j=1:2
      plot(ax1, (i+j):(i+j+4), j:(j+4))
      errorbar(ax1, (i+j+1):(i+j+5), j:(j+4))
      plot(ax2, (i+j):(i+j+4), j:(j+4))
      errorbar(ax2, (i+j+1):(i+j+5), j:(j+4))
   end
end

[franco otaola]

hello, thanks for the answer and taking the effort of trying to understand, it is a little bit difficult to explain ahaha.

I still have some issues,

1. some of my plots have a secondary axis, that (at least for the moment) was creating by doing yyaxis left and yyaxis right, not sure how can use them with this approach.
2. what I meant in my first post was, when I get an output as your first code (with secondary axis) from the script itself or by opening a fig file. after this being able to create another figure with the subplots of these figures as I want. To be more clear, I run my code, I finish with fig 1, 2 and 3, now (what I was trying to ask...) i said to myself ok, I should put fig 2 with 3 in one, so, subplot(1,2,1) =fig 2, subplot(1,2,2)= fig 3 (I know it does not work like that but thats what I meant to ask)

[Benjamin Kraus]

Handling yyaxis with this approach is pretty straightforward. For example:

ax = axes;
yyaxis(ax,'left')
plot(ax, 1:10)
yyaxis(ax,'right')
errorbar(ax, 11:20, 1:10, 0.1:0.1:1)

As for moving axes from one figure to another, that is a bit tricker. One thing to note is the distinction between a figure (which represents a window that contains some graphics) vs. an axes (which is one set of x-ruler + y-ruler + ticks + the data inside). What I suspect you want to do is to take the axes that are within a saved figure, and move them into another new figure. Here is one way to do that using tiledlayout.

f1 = figure;
ax1 = axes(f1);
plot(ax1, 1:10)
savefig(f1,'fig1')
close(f1)

f2 = figure;
ax2 = axes(f2);
plot(ax2, sin(1:10))
savefig(f2, 'fig2')
close(f2)

% I'll put two axes into this figure, just to show how that might change
% things.
f3 = figure;
t = tiledlayout(f3,'flow');
ax3 = nexttile(t);
plot(ax3, 11:20)
ax4 = nexttile(t);
plot(ax4, cos(1:10))
savefig(f3, 'fig3')
close(f3)

% Now create a new figure to contain the contents of the other figures.
fnew = figure;

% Put a tiledlayout into the figure to hold all the axes from the other
% figures.
tnew = tiledlayout(fnew, 'flow');

% Create a list of fig files to load.
figFiles = ["fig1", "fig2", "fig3"];
numAxes = 0;
for f = 1:numel(figFiles)
    % Load the fig file
    loadedFig = openfig(figFiles(f));
    
    % Find all the axes in the figure.
    ax = findobj(loadedFig, 'Type', 'axes');
    
    % Move the axes into the new tiledlayout.
    for a = 1:numel(ax)
        numAxes = numAxes + 1;
        
        % Set the parent of the axes to be the new tiled layout, which will
        % move the axes into that new figure.
        ax(a).Parent = tnew;
        
        % Set the Layout.Tile to a unique number so that each axes will not
        % overlap other axes.
        ax(a).Layout.Tile = numAxes;
    end
    
    % Now close the empty loaded figure.
    close(loadedFig);
end

[franco otaola]

Thanks a lot! now i understand a little bit better, what I was tying to do, was a combination of the two codes you gently posted. have two plots one that have two axis (and not two subplots) in the same figure. I adapted from your script if anyone comes across this post. in any case, thanks a lot!

EDIT: also for what concerned my initial quesiton we can also stock multiple axis inside a variable

f1 = figure;

ax1 = axes(f1);

plot(ax1, 1:10)

savefig(f1,'fig1')

close(f1)

f2 = figure;

ax2 = axes(f2);

plot(ax2, sin(1:10))

savefig(f2, 'fig2')

close(f2)

% I'll put two axes into this figure, just to show how that might change

% things.

f3 = figure;

ax=axes(f3)

yyaxis(ax,'left')

plot(ax, 1:10)

yyaxis(ax,'right')

plot(ax, 1:20,'*')

savefig(f3, 'fig3')

close(f3)

% Now create a new figure to contain the contents of the other figures.

fnew = figure;

% Put a tiledlayout into the figure to hold all the axes from the other

% figures.

tnew = tiledlayout(fnew, 'flow');

% Create a list of fig files to load.

figFiles = ["fig1", "fig2", "fig3"];

numAxes = 0;

for f = 1:numel(figFiles)

% Load the fig file

loadedFig = openfig(figFiles(f));

% Find all the axes in the figure.

ax = findobj(loadedFig, 'Type', 'axes');

% Move the axes into the new tiledlayout.

for a = 1:numel(ax)

numAxes = numAxes + 1;

% Set the parent of the axes to be the new tiled layout, which will

% move the axes into that new figure.

ax(a).Parent = tnew;

% Set the Layout.Tile to a unique number so that each axes will not

% overlap other axes.

ax(a).Layout.Tile = numAxes;

end

% Now close the empty loaded figure.

close(loadedFig);

end