Matplotlib Connection Patch Visualization

Introduction

Matplotlib is a powerful data visualization library in Python. It provides a variety of visualization tools to create stunning graphics and charts. In this lab, we will learn about ConnectionPatch, which is used to draw a line between points defined in different coordinate systems and/or axes.

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Skills Graph

Import the necessary libraries

Before we start, let's import the necessary libraries.

import matplotlib.pyplot as plt
from matplotlib.patches import ConnectionPatch

Create the plot

Next, let's create the plot with two subplots.

fig, (ax1, ax2) = plt.subplots(1, 2, figsize=(6, 3))

Draw a simple arrow

Now, let's draw a simple arrow between two points in axes coordinates within a single axes.

xyA = (0.2, 0.2)
xyB = (0.8, 0.8)
coordsA = "data"
coordsB = "data"
con = ConnectionPatch(xyA, xyB, coordsA, coordsB,
                      arrowstyle="-|>", shrinkA=5, shrinkB=5,
                      mutation_scale=20, fc="w")
ax1.plot([xyA[0], xyB[0]], [xyA[1], xyB[1]], "o")
ax1.add_artist(con)

Draw an arrow between different axes

Let's draw an arrow between the same point in data coordinates, but in different axes.

xy = (0.3, 0.2)
con = ConnectionPatch(
    xyA=xy, coordsA=ax2.transData,
    xyB=xy, coordsB=ax1.transData,
    arrowstyle="->", shrinkB=5)
fig.add_artist(con)

Draw a line between the different points

Finally, let's draw a line between the different points, defined in different coordinate systems.

con = ConnectionPatch(
    ## in axes coordinates
    xyA=(0.6, 1.0), coordsA=ax2.transAxes,
    ## x in axes coordinates, y in data coordinates
    xyB=(0.0, 0.2), coordsB=ax2.get_yaxis_transform(),
    arrowstyle="-")
ax2.add_artist(con)

Summary

In this lab, we learned about ConnectionPatch, which is used to draw a line between points defined in different coordinate systems and/or axes. We also learned how to draw a simple arrow and a line between different points in a plot.