plot a graph with two axis

Hi there,

I have a matrix 1440x3 and I would like to plot a graph with two axes. (x axis the same = 1440 elements)

the first two columns vary from -0.4 to 1.2, and the third one from 80 to 90.

how can I do this?

thanks a lot

Nikolas

Answer 1

[alice]

You can do like this, using yyaxis:

% fake data generation:
myMatrix = [(1.2-(-0.4))*rand(20,2)+(-0.4) , sort((90-80)*rand(20,2)+80)];
% figure with two y-axis:
figure;
yyaxis left                         % select the left y-axis
plot(myMatrix(:,3),myMatrix(:,1));  % plot (left y-axis)
ylabel('column 1');                 % label the y-axis
yyaxis right                        % select the right y-axis
plot(myMatrix(:,3),myMatrix(:,2));  % plot (right y-axis)
ylabel('column 2');                 % label the y-axis
xlabel('column 3');

[Nikolas Spiliopoulos]

thanks for the answer, I tried this but

It doesn't keep the x axis as a common one (FROM 1 to 1440)

[alice]

OK, sorry I hadn't got you right, just modify the plots to get what you want, most probably something like:

% fake data generation:
myMatrix = [(1.2-(-0.4))*rand(1440,2)+(-0.4) , (90-80)*rand(1440,2)+80];
% figure with two y-axis:
figure;
yyaxis left                         % select the left y-axis
hold on;
plot(1:size(myMatrix,1),myMatrix(:,1),'k-');  % plot (left y-axis)
plot(1:size(myMatrix,1),myMatrix(:,2),'b-');  % plot (left y-axis)
yyaxis right                        % select the right y-axis
plot(1:size(myMatrix,1),myMatrix(:,3),'r-');  % plot (right y-axis)
legend('column 1','column 2','column 3')
xlabel('index');

[Nikolas Spiliopoulos]

thanks a lot it worked!!!