Separate graph arrows for two y-axes on the matlab

In the figure below, the circle arrows are used for two y-axes to indicate which axis the graph follows, how do you do this?

Answer 1

[sai charan sampara]

Hello,

You can try to acheive a similar result by using the "annotations" feature in MATLAB. The following code shows an example for plotting an ellipse and an arrow:

figure
x = linspace(-4,4);
y = x.^3 - 12*x;
plot(x,y)

dim = [.4 .55 .1 .25];
annotation('ellipse',dim)
annotation('arrow',[dim(1),dim(1)-dim(3)/2],[dim(2)+dim(4)/2,dim(2)+dim(4)/2])

The "dim" vector gives the the size and location of the smallest rectangle that encloses the ellipse. The dimensions of the arrow can also be defined separately as per requirement. The values are in normalized units. This can be changed by changing the "Units" property. Here is the link to the documentation for "annotations":

• https://www.mathworks.com/help/matlab/ref/annotation.html
• https://www.mathworks.com/help/matlab/ref/matlab.graphics.shape.ellipse-properties.html#:~:text=Units%20%E2%80%94%20Position%20units

Answer 2

[Angelo Yeo]

To add Sai's answer, you can change the color of annotations like below.

EDIT: Fixed the direction of the second arrow as @Aquatris pointed out.

colors = lines(2);

x = linspace(0,10);
y = sin(3*x);
yyaxis left
plot(x,y)
dim = [.4 .55 .1 .25];
annotation('ellipse',dim, 'Color', colors(1,:))
annotation('arrow',[dim(1),dim(1)-dim(3)/2],[dim(2)+dim(4)/2,dim(2)+dim(4)/2], 'Color', colors(1,:))

z = sin(3*x).*exp(0.5*x);
yyaxis right
plot(x,z)
ylim([-150 150])
dim = [.6 .55 .1 .25];
annotation('ellipse',dim, 'Color', colors(2,:))
annotation('arrow',[dim(1)+dim(3), dim(1)+dim(3)+dim(3)/2],[dim(2)+dim(4)/2,dim(2)+dim(4)/2], 'Color', colors(2,:))

[Aquatris]

Red arrow seems to be showing the wrong way Angelo :P