How to plot half or quarter polar plots in Matplotlib?

To plot half or quarter polar plots in Matplotlib, we can control the angular range using the set_thetamax() and set_thetamin() methods. This allows us to create partial polar plots that show only specific angular segments.

Steps to Create Partial Polar Plots

• Set the figure size and adjust the padding between and around the subplots.

• Create a new figure or activate an existing figure using figure() method.

• Add an axes to the figure as part of a subplot arrangement with projection="polar".

• For half or quarter polar plots, use set_thetamax() method to limit the maximum angle.

• Optionally use set_thetamin() to set the minimum angle.

• To display the figure, use show() method.

Quarter Polar Plot Example

Here's how to create a quarter polar plot (90 degrees) ?

import matplotlib.pyplot as plt
import numpy as np

plt.rcParams["figure.figsize"] = [7.50, 3.50]
plt.rcParams["figure.autolayout"] = True

fig = plt.figure()
ax = fig.add_subplot(111, projection="polar")

# Set maximum angle to 90 degrees for quarter plot
max_theta = 90
ax.set_thetamax(max_theta)

# Add some sample data
theta = np.linspace(0, np.radians(90), 100)
r = theta

ax.plot(theta, r)
plt.show()

Half Polar Plot Example

To create a half polar plot, set the maximum angle to 180 degrees ?

import matplotlib.pyplot as plt
import numpy as np

plt.rcParams["figure.figsize"] = [7.50, 3.50]
plt.rcParams["figure.autolayout"] = True

fig = plt.figure()
ax = fig.add_subplot(111, projection="polar")

# Set maximum angle to 180 degrees for half plot
ax.set_thetamax(180)

# Add some sample data
theta = np.linspace(0, np.radians(180), 100)
r = np.sin(2 * theta)

ax.plot(theta, r)
plt.show()

Custom Angular Range

You can also create custom angular ranges by combining set_thetamin() and set_thetamax() ?

import matplotlib.pyplot as plt
import numpy as np

plt.rcParams["figure.figsize"] = [7.50, 3.50]
plt.rcParams["figure.autolayout"] = True

fig = plt.figure()
ax = fig.add_subplot(111, projection="polar")

# Custom range from 45 to 135 degrees
ax.set_thetamin(45)
ax.set_thetamax(135)

# Add some sample data
theta = np.linspace(np.radians(45), np.radians(135), 100)
r = np.ones_like(theta)

ax.plot(theta, r)
plt.show()

Common Angular Ranges

Conclusion

Use set_thetamax() to create quarter, half, or custom polar plots by limiting the angular range. Combine with set_thetamin() for precise control over the displayed angular segment.