How to Annotate in Matplotlib

In this tutorial, we’ll look at how to add an annotation to the plot using the annotate() method with Matplotlib in Python.

Use the annotate() Method to Add Annotation to the Plot in Matplotlib

The plot annotation adds the note to the diagram or text to explain that point in the diagram or text. We can do the same way to add an annotation to the plot using the annotate() method.

There is another method of Matplotlib called text(). It also allows us to add the annotation to the plot but compared to the annotate() method, the text() method has very basic features.

The syntax of the annotate() method.

annotate(s, xy, *args, **kwargs)

Code:

import matplotlib.pyplot as plot

plot.plot([10, 20, 30, 40], marker="o")

plot.annotate("Points", (1, 20))
plot.show()

Output:

This next example is with the xytext and *args argument.

Code:

import matplotlib.pyplot as plot

plot.plot([10, 20, 30, 40], marker="o")

plot.annotate("Points", (1, 20), (0.5, 25), size=20, color="red")
plot.show()

Output:

We can add an arrow using the arrowprops property of the annotate() method.

Code:

import matplotlib.pyplot as plot

plot.plot([10, 20, 30, 40], marker="o")

plot.annotate("Points", (1, 20), (0.5, 25), arrowprops={})
plot.show()

Output:

We can change the style of the arrow using the arrowstyle key.

Code:

import matplotlib.pyplot as plot

plot.plot([10, 20, 30, 40], marker="o")

plot.annotate("Points", (1, 20), (0.5, 25), arrowprops={"arrowstyle": "<->"})
plot.show()

Output:

We can also use the width key to increase the arrow’s width, but we can not use the width and arrowstyle keys together. If we do this, then we will get an error.

We can only use this key when we do not use the key as arrowstyle.

Code:

import matplotlib.pyplot as plot

plot.plot([10, 20, 30, 40], marker="o")

plot.annotate("Points", (1, 20), (0.5, 25), arrowprops={"width": 10})
plot.show()

Output:

We can hide the annotation using the annotation_clip property when the coordinates of the annotation are outside of axes, so we will need to pass it the Boolean value as "True", but we want to see the annotation even the annotation coordinates are placed at outside the plot, so we pass it "False".

Code:

import matplotlib.pyplot as plot

plot.plot([10, 20, 30, 40], marker="o")

plot.annotate(
    "Points",
    (1, 20),
    (0.5, 45),
    arrowprops={"arrowstyle": "<->"},
    annotation_clip=False,
)
plot.show()

Output: