MATLAB Draw Arrow

1. Add an Arrow on a Plot Using the annotation() Function in MATLAB
2. Adding an Arrow on a Plot Using the text() Function in MATLAB

This tutorial will discuss adding an arrow on a plot using the annotation() and text() function in MATLAB.

Add an Arrow on a Plot Using the annotation() Function in MATLAB

To add an arrow with some text on a plot in MATLAB, you can use the annotation() function. The annotation() function creates an arrow with given dimensions on the plot. For example, let’s plot a sine wave and add an arrow to it. See the code below.

t = 1:0.01:2;
x = sin(2*pi*t);
figure
plot(t,x)
dimen = [.3 .1 .5 .5];
a = annotation('arrow','Position',dimen)

Output:

In the above code, you can change the dimensions of the arrow according to your requirements. You can also change the color of the arrow using the Color property, the line style using the LineStyle property, the line width using the LineWidth property, the style of the head using the HeadStyle property, and position of the arrow using the Position property. For example, let’s change all these properties of the arrow using a function handle. See the code below.

t = 1:0.01:2;
x = sin(2*pi*t);
figure
plot(t,x)
dimen = [.3 .1 .5 .5];
a = annotation('arrow',[0.31 0.4],[0.7 0.8])
a.Position = dimen;
a.Color = [1 0 0];
a.LineWidth = 2;
a.HeadStyle = 'vback3';

Output:

In the above code, we changed the color of the arrow to red, the line width of the arrow to 2, and the style of the head to vback3. The function handle a will display all the arrow properties on the command window, which we can change using the function handle a. Check this link for more details about the annotation() function.

Adding an Arrow on a Plot Using the text() Function in MATLAB

You can also use the text() function to add an arrow to the plot. You need to pass the x and y coordinate on which you want to place the text along with the arrow. Simply plot the variable, select the coordinates from the plot, and then use the text() function to place the text and the arrow on the selected coordinates. If you give the coordinates which don’t lie on the plot, you won’t see the text and the arrow. You can also change the properties of the text like the font size using the FontSize property and the color using the Color property etc. For example, let’s plot a cosine wave and put some text with an arrow on it with font size 18 and red color and a black box around the text. See the code below.

t = 1:0.01:2;
plot(cos(2*pi*t))
tex = text(20,0.8,'\leftarrowCosine wave','FontSize',18,'Color','r')

Output:

You can give your desired color to the text using the Color property and the font size using the FontSize property. You can also add multiple texts with arrows at multiple positions on the plot with different text, line styles, color, size, and box. Check this link for more details about the text() function.