Why the subplot is missed after adjusting the position

Hi all,

I want to use "subplot" function to draw multiple figures in one window and want these figures be tight along y axis. However, when I used the following example codes to construct the plot, one is missed, can any one help me to solve this problem?

a = randn(30,1);
for ii = 1:4
  subplot(4,1,ii)
  plot(a)
  set(gca,'XTick',[],'YTick',[],'TickLength',[0,0],...
      'XColor','b','YColor','b',...
      'Position',[0.01,0.01+0.245*(4-ii),0.98,0.245])
end

Result after running such codes is:

But everything seems OK if I do not set "Position" of each subplot. Is this a bug? Thanks in advance.

Answer 1

[Azzi Abdelmalek]

Because your position are not well chosen. Try this for example

a = randn(30,1);
for ii = 1:4
subplot(4,1,ii)
plot(a)
set(gca,'XTick',[],'YTick',[],'TickLength',[0,0],...
    'XColor','b','YColor','b',...
    'Position',[0.01,0.2+0.2*(4-ii),0.98,0.15])
end

[Jorey]

Thanks, your codes work. But I wonder why this phenomenon occurs. According to the document, the second element in position vector, i.e., 0.2+0.2*(4-ii) in your "Position" value, is the bottom of a subplot. So if my setting is out of window, part of the subplot should be shown, as shown in follow figure.

The position I set is

set(gca,'XTick',[],'YTick',[],'TickLength',[0,0],...
  'XColor','b','YColor','b',...
  'Position',[0.01,0.1+0.245*(4-ii),0.98,0.245])

As shown, because coordinate of the top of first subplot is higher than 1 which exceeds the edge of the figure window, it was cut, but the whole subplot was not removed.

So why my subplot is lost?

[Tony Castillo]

Dear all,

I am using your code for make the subplots in my case only five, one per loop iteraction, but I have noticed that at the end the five of them are repeated as if they were plotted and pasted five times. I think it worths mentioning these are part of a upper for loop.

    figure
    for scenario=1:3
    subplot(3,1,scenario)
    h_bp=boxplot([SOC_, SOC_Max, SOC_mean], 'Labels',{'SOC','SOC(Max)','SOC(mean)'});
    hold on
    ylabel('State of charge (%)')
    hold off
    end

Any insight to overcome this?

Best regards

Answer 2

[Walter Roberson]

subplot() is defined to remove any existing axis that it overlaps with at all. If the Position of the 3rd subplot is at all overlapping the position that is automatically calculated for the 4th subplot then the third subplot will be deleted.

If you are going to set the Position of subplots, create all the subplots first, then set their Positions and draw in them.

[Jorey]

I don't think the third subplot overlaps the forth subplot. Positions of the four subplots are ([left bottom width height], consistent with MATLAB's documentation):

0.01 0.745 0.98 0.245

0.01 0.5 0.98 0.245

0.01 0.255 0.98 0.245

0.01 0.01 0.98 0.245

And why the second subplot is still displayed?

[Walter Roberson]

Remember that the Position of the 4th subplot does not take effect until after you have already created the 4th axes using subplot(4,1,4), at which time it calculates the position it would prefer to use and determines whether that overlaps with any previous axes.

Remember too that you need to take into account OuterPosition not just Position.

Try this:

clf
ax4 = subplot(4,1,4);
ax4pos = get(ax4, 'OuterPosition');
delete(ax4);
rectangle('Position', ax4pos, 'EdgeColor', 'r');  %where it would have gone
rectangle('Position', [0.01 0.255 0.98 0.245], 'EdgeColor', 'g');  %where your third subplot has its Position

You can see that they quite obviously overlap, not even taking into account the proper OuterPosition for your third axes.

[Jorey]

But why all subplots are displayed if I adjust the bottom value of each subplot but keep other parameters for defining "Position" (see my comment of the first answer)?

Further, I have tested your hypothesis, found that second subplot overlaps third one, same situation which third subplot meets when 4th is added, why the second subplot is displayed?

[Walter Roberson]

At least up to R2014a, subplot() is a .m file that you can debug. You can spend a couple of hours determining exactly what is happening.

Or you can learn the lesson without that effort and simply create all the subplots before you change their Positions.

I have been up all night answering questions, so at the moment I am completely willing to say that the answer is that "You let the magic smoke get out, and that is why it doesn't work anymore."

[Jorey]

I'm very appreciated for your kink help. But I tried your suggestion, it did not work. The problem is solved by manual adjusting...

I wonder whether this can be done automatically without tedious manual operation.

Answer 3

[Cao Xuan Canh]

You could try with ii = 4:-1:1

Because the 4th is generated automatically (as default- axis... due to subplot(4....)) before you set position for the 3rd. If the 3rd overlapping the auto-4th (due to the subplots bigger the default) then it will be deleted (loss).

So, you set the possition for the last first, and it can not be overlapped.

If the subplots smaller the default, you can take ii=1:4...