Viewing angle control in Matplotlib - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the elevation angle after this code runs?

Consider this code that sets the elevation angle of a 3D plot. What will be the elevation angle printed?

Matplotlib

import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
ax.view_init(elev=30, azim=45)
elev = ax.elev
print(elev)

A None

B 45

C 0

D 30

💡 Hint

The elev parameter sets the elevation angle in degrees.

The method view_init sets the elevation (elev) and azimuth (azim) angles. Here elev=30 means the elevation angle is 30 degrees.

❓ data_output

intermediate

What is the azimuth angle after setting view_init?

After running this code, what is the azimuth angle stored in ax.azim?

Matplotlib

import matplotlib.pyplot as plt
fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
ax.view_init(elev=10, azim=120)
azim = ax.azim
print(azim)

A 120

B None

C 0

D 10

💡 Hint

The azim parameter controls the azimuth angle in degrees.

The azim parameter in view_init sets the azimuth angle. Here it is set to 120 degrees.

❓ visualization

advanced

Which option shows the correct azimuth and elevation for this 3D plot?

This code creates a 3D plot and sets the viewing angle. Which option correctly describes the viewing angles used?

Matplotlib

import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
import numpy as np
fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
X = np.linspace(-5, 5, 100)
Y = np.linspace(-5, 5, 100)
X, Y = np.meshgrid(X, Y)
Z = np.sin(np.sqrt(X**2 + Y**2))
ax.plot_surface(X, Y, Z, cmap='viridis')
ax.view_init(elev=60, azim=30)
plt.show()

A Elevation 30°, Azimuth 60°

B Elevation 0°, Azimuth 0°

C Elevation 60°, Azimuth 30°

D Elevation 45°, Azimuth 45°

💡 Hint

Check the parameters passed to view_init(elev=..., azim=...).

The code sets elev=60 and azim=30, so the viewing angle is elevation 60°, azimuth 30°.

🔧 Debug

advanced

What error does this code raise?

This code tries to set the viewing angle but has a mistake. What error will it raise?

Matplotlib

import matplotlib.pyplot as plt
fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
ax.view_init(elevation=45, azimuth=90)

A TypeError: view_init() got an unexpected keyword argument 'elevation'

B AttributeError: 'Axes3D' object has no attribute 'view_init'

C ValueError: Elevation angle must be between 0 and 90

D No error, runs successfully

💡 Hint

Check the parameter names for view_init method.

The method view_init expects parameters named elev and azim, not elevation or azimuth.

🚀 Application

expert

How to programmatically rotate a 3D plot by 10 degrees azimuth each frame?

You want to create an animation that rotates a 3D plot by increasing the azimuth angle by 10 degrees every frame, starting from 0°. Which code snippet correctly updates the azimuth angle inside a loop?

Matplotlib

import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
import numpy as np
fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
X = np.linspace(-5, 5, 100)
Y = np.linspace(-5, 5, 100)
X, Y = np.meshgrid(X, Y)
Z = np.sin(np.sqrt(X**2 + Y**2))
ax.plot_surface(X, Y, Z, cmap='coolwarm')
for i in range(0, 360, 10):
    # Update viewing angle here
    pass
    plt.pause(0.1)

A ax.view_init(elev=i, azim=30)

B ax.view_init(elev=30, azim=i)

C ax.view_init(elev=0, azim=i*10)

D ax.view_init(elev=30, azim=i*10)

💡 Hint

The azimuth angle changes by i degrees each loop, elevation stays fixed.

To rotate by azimuth angle increasing by 10 degrees each frame, set azim=i and keep elev fixed (e.g., 30).