CODEWITHSUNDEEP
matlabplot
Balraj Boyal
Balraj Boyal

Reputation: 155

Matlab: Change plot axis to get the [0,0] point in the middle of the plot

I am trying to plot some 2D lines with Matlab. I am trying to get the plot to show the intersection point between the x-axis and y-axis in the middle of the plot so I can see how the lines proceed in the negative x-range and y-range.

I've tried the axis command. But this will just scale the XMIN XMAX YMIN YMAX... etc in the plot

enter image description here

Thanks!

here is my code for plotting:

plot(AOA,y,'g-o')
hold on 
pl = plot(AOA,CLspanloading,'c-o');
 set(pl,'linewidth',2);
xlabel('Alpha')
ylabel('CL')
title('Lift Polar')
axis([-5 8 -1 1.5])
% legend('LowerCL','UpperCL','-Spanloading','Location','SouthEast')
legend('F27 Paper','Spanloading','Location','SouthEast')

Upvotes: 0

Views: 1151

Answers (2)

gariepy
gariepy

Reputation: 3674

You can also use xlim and ylim to adjust the scale of the current axes:

xlim([XMIN XMAX]);
ylim([YMIN YMAX]);

And to center the axis on the origin in the plot, make sure the magnitudes of XMIN/XMAX are the same, as well as the magnitudes of YMIN/YMAX:

xlim([-XMAX XMAX]);
ylim([-YMAX YMAX]);

Upvotes: 1

AlessioX
AlessioX

Reputation: 3177

The axis command must be used wisely. The XMIN and the XMAX should have the same value and the same goes for YMIN ad YMAX. The only thing that must be changed, is the sign: indeed, XMIN=-XMAX and YMIN=-YMAX (where, of course XMAX>0 and YMAX>0).

By running this simple code

plot(1:50,1:50,'g-o')
xlabel('Alpha')
ylabel('CL')
title('Lift Polar')
axis([-8 8 -8 8]); grid on;

i get

enter image description here

Now, sure this line doesn't mean a thing...it's just for demo purposes. But as you can see the origin is exactly in the middle of the plot.

Upvotes: 2

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