Matlab. Place legend outside the plot

4
votes

I have the following code

T = [0:1:30]
a = [5:1:35]; a2 = [0:1:30];
b = [-4:1:26]; b2 = [12:1:42];
c = [16:1:46]; c2 = [15:1:45];
d = [2:1:32]; d2 = [-5:1:25];
figure(1)
title('Time histories of output variables (measured vs estimated)')
subplot(411),plot(T,a, T,a2,'r'); grid; ylabel('p (°/s)'); 
subplot(412),plot(T,b, T,b2,'r'); grid; ylabel('r (°/s)');
subplot(413),plot(T,c, T,c2,'r'); grid; ylabel('phi (º)');
subplot(414),plot(T,d, T,d2,'r'); grid; ylabel('ay (m/s2)');
legend('measured','estimated','Location','bestoutside')
xlabel('Time [s]');

Which generates the following plot enter image description here

I would like to have the legend outside the plot and that all of them remains with the normal size. (So the legend should be in one of those red circles. Any solutions?

2
matlabplotlegend

2 Answers

8
votes

You could add another subplot to act as an empty region to hold only the legend, with the axes visibility turned off and nan values for the 'YData' of the plotted lines, so they don't render:

figure(1);
hSub = subplot(511); plot(1, nan, 1, nan, 'r'); set(hSub, 'Visible', 'off');
subplot(512); plot(T, a, T, a2, 'r'); grid; ylabel('p (°/s)');
subplot(513); plot(T, b, T, b2, 'r'); grid; ylabel('r (°/s)');
subplot(514); plot(T, c, T, c2, 'r'); grid; ylabel('phi (º)');
subplot(515); plot(T, d, T, d2, 'r'); grid; ylabel('ay (m/s2)');
xlabel('Time [s]');
legend(hSub, 'measured', 'estimated', 'Location', 'east');

And here's the result:

enter image description here

1
votes

Try getting handle positions using get method and manually change positions by doing some arithmetic. For example,

T = [0:1:30];
a = [5:1:35]; a2 = [0:1:30];
b = [-4:1:26]; b2 = [12:1:42];
c = [16:1:46]; c2 = [15:1:45];
d = [2:1:32]; d2 = [-5:1:25];
figure(1)

title('Time histories of output variables (measured vs estimated)')

f1 = subplot(411);plot(T,a, T,a2,'r'); grid; ylabel('p (°/s)'); 
pos_f1 = get(f1,'Position');
hl = legend('measured','estimated','Location','bestoutside');
pos_hl = get(hl, 'Position');

subplot(412),plot(T,b, T,b2,'r'); grid; ylabel('r (°/s)');
subplot(413),plot(T,c, T,c2,'r'); grid; ylabel('phi (º)');
subplot(414),plot(T,d, T,d2,'r'); grid; ylabel('ay (m/s2)');

set(hl,'Position',[pos_f1(1)+pos_f1(3)-pos_hl(3)...
pos_hl(2)+pos_hl(4)+0.015...
pos_hl(3)...
0.5*pos_hl(4)]);

This should give you:subplot with changed position

You may need to play around with the parameters in last line, but you get the idea.