Zoom Inset Axes

Introduction

Matplotlib is a Python library used for creating static, animated, and interactive visualizations in Python. It is a powerful tool for data visualization, and it is widely used in the scientific community. In this lab, we will learn how to create a zoomed-in region in a Matplotlib plot.

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Skills Graph

Import necessary libraries

The first step is to import the necessary libraries. We will be using NumPy and Matplotlib for this example.

import numpy as np
from matplotlib import cbook
from matplotlib import pyplot as plt

Create the plot

Next, we will create a plot using some sample data. We will be using a bivariate normal distribution as our data source.

fig, ax = plt.subplots()

## make data
Z = cbook.get_sample_data("axes_grid/bivariate_normal.npy")  ## 15x15 array
Z2 = np.zeros((150, 150))
ny, nx = Z.shape
Z2[30:30+ny, 30:30+nx] = Z
extent = (-3, 4, -4, 3)

ax.imshow(Z2, extent=extent, origin="lower")

Add an inset plot

In this step, we will add an inset plot to the main plot. This inset plot will show a zoomed-in region of the main plot.

## inset axes....
x1, x2, y1, y2 = -1.5, -0.9, -2.5, -1.9  ## subregion of the original image
axins = ax.inset_axes(
    [0.5, 0.5, 0.47, 0.47],
    xlim=(x1, x2), ylim=(y1, y2), xticklabels=[], yticklabels=[])
axins.imshow(Z2, extent=extent, origin="lower")

Add a rectangle to show the zoomed-in region

In this step, we will add a rectangle to the main plot to show where the zoomed-in region is located.

ax.indicate_inset_zoom(axins, edgecolor="black")

Display the plot

Finally, we will display the plot using the plt.show() function.

plt.show()

Summary

In this lab, we learned how to create a zoomed-in region in a Matplotlib plot. We created a main plot using sample data, added an inset plot to show a zoomed-in region of the main plot, and added a rectangle to show where the zoomed-in region is located. We then displayed the plot using the plt.show() function.