Subplot spacing adjustment in Matplotlib

Introduction

We adjust subplot spacing to make sure plots do not overlap and look neat. It helps in clear visualization when multiple plots are shown together.

When you have multiple plots in one figure and their titles or labels overlap.

When you want to add more space between plots for better readability.

When the default spacing makes the plots look crowded or cluttered.

When you want to control the margins around the plots.

When adding annotations or legends that need extra space.

Syntax

Matplotlib

plt.subplots_adjust(left=None, right=None, top=None, bottom=None, wspace=None, hspace=None)

left, right, top, bottom control the margins of the whole figure (values between 0 and 1).

wspace and hspace control the width and height space between subplots (fraction of average subplot size).

Examples

Adds more space between subplots horizontally and vertically.

Matplotlib

plt.subplots_adjust(wspace=0.5, hspace=0.5)

Sets the margins of the figure to leave space around the edges.

Matplotlib

plt.subplots_adjust(left=0.1, right=0.9, top=0.9, bottom=0.1)

Increases horizontal space between subplots only.

Matplotlib

plt.subplots_adjust(wspace=0.2)

Sample Program

This code creates two figures with 2x2 subplots each. The first figure uses default spacing, which may look crowded. The second figure increases horizontal and vertical space between subplots for clarity.

Matplotlib

import matplotlib.pyplot as plt

fig, axs = plt.subplots(2, 2)

for i, ax in enumerate(axs.flat, 1):
    ax.plot([1, 2, 3], [i, i*2, i*3])
    ax.set_title(f'Plot {i}')

# Default spacing
plt.suptitle('Default spacing')
plt.show()

fig, axs = plt.subplots(2, 2)
for i, ax in enumerate(axs.flat, 1):
    ax.plot([1, 2, 3], [i, i*2, i*3])
    ax.set_title(f'Plot {i}')

# Adjust spacing
plt.subplots_adjust(wspace=0.5, hspace=0.7)
plt.suptitle('Adjusted spacing')
plt.show()

Important Notes

You can call plt.subplots_adjust() after creating subplots to change spacing anytime before showing the plot.

Values for spacing parameters are fractions of the figure or subplot size, so try small changes and see the effect.

Summary

Adjust subplot spacing to avoid overlapping and improve plot clarity.

Use plt.subplots_adjust() with parameters like wspace and hspace to control space between plots.

Margins can be controlled with left, right, top, and bottom.

Practice

1. What does the plt.subplots_adjust() function do in matplotlib?

easy

A. It changes the space between subplots in a figure.

B. It creates new subplots in a figure.

C. It saves the figure to a file.

D. It changes the color of the plot lines.

Solution

1. Step 1: Understand the purpose of plt.subplots_adjust()

   This function is used to control the spacing between subplots in a matplotlib figure.

2. Step 2: Compare options

   Only It changes the space between subplots in a figure. correctly describes adjusting space between subplots. Other options describe different functions.

3. Final Answer:

   It changes the space between subplots in a figure. -> Option A

4. Quick Check:

   Subplot spacing adjustment = plt.subplots_adjust() [OK]

Hint: Remember: adjust spacing, not create or save plots [OK]

Common Mistakes:

• Confusing subplot creation with spacing adjustment
• Thinking it saves the figure
• Mixing it with styling functions

2. Which of the following is the correct syntax to increase horizontal space between subplots using plt.subplots_adjust()?

easy

A. plt.subplots_adjust(hspace=0.5)

B. plt.subplots_adjust(space=0.5)

C. plt.subplots_adjust(wspace=0.5)

D. plt.subplots_adjust(widthspace=0.5)

Solution

1. Step 1: Identify parameter for horizontal spacing

   The parameter wspace controls horizontal space between subplots.

2. Step 2: Check syntax correctness

   plt.subplots_adjust(wspace=0.5) uses wspace=0.5, which is correct. Other options use incorrect or non-existent parameters.

3. Final Answer:

   plt.subplots_adjust(wspace=0.5) -> Option C

4. Quick Check:

   wspace adjusts horizontal space [OK]

Hint: Use wspace for width (horizontal), hspace for height (vertical) [OK]

Common Mistakes:

• Using hspace instead of wspace for horizontal spacing
• Using wrong parameter names like space or widthspace
• Syntax errors in function call

3. What will be the effect of this code on subplot spacing?

import matplotlib.pyplot as plt
fig, axs = plt.subplots(1, 2)
plt.subplots_adjust(wspace=1.0)
plt.show()

medium

A. Subplots will have increased horizontal space between them.

B. Subplots will be very close horizontally with almost no space.

C. Subplots will overlap each other.

D. Subplots will have increased vertical space between them.

Solution

1. Step 1: Understand wspace=1.0 effect

   Setting wspace to 1.0 increases horizontal space between subplots significantly.

2. Step 2: Analyze code behavior

   Since there are 2 subplots side by side, they will be spaced apart horizontally, not vertically.

3. Final Answer:

   Subplots will have increased horizontal space between them. -> Option A

4. Quick Check:

   wspace=1.0 means more horizontal space [OK]

Hint: wspace controls horizontal gap size between subplots [OK]

Common Mistakes:

• Confusing wspace with hspace
• Expecting subplots to overlap
• Thinking spacing affects vertical gap

4. Identify the error in this code that tries to adjust subplot spacing:

import matplotlib.pyplot as plt
fig, axs = plt.subplots(2, 1)
plt.subplots_adjust(wspace=0.3, hspace=0.5)
plt.show()

medium

A. Using hspace with vertical subplots is invalid.

B. Using wspace when subplots are stacked vertically.

C. Incorrect number of subplots created.

D. Missing plt.show() call.

Solution

1. Step 1: Analyze subplot layout

   The code creates 2 subplots stacked vertically (2 rows, 1 column).

2. Step 2: Check spacing parameters

   wspace controls horizontal spacing, which is irrelevant here because subplots are vertical. Only hspace affects vertical spacing.

3. Final Answer:

   Using wspace when subplots are stacked vertically. -> Option B

4. Quick Check:

   wspace for horizontal, not vertical spacing [OK]

Hint: Match wspace to horizontal, hspace to vertical layout [OK]

Common Mistakes:

• Using wspace for vertical subplot spacing
• Ignoring subplot grid shape
• Assuming hspace is invalid for vertical layout

5. You have a 2x2 grid of subplots with overlapping x-axis labels. Which plt.subplots_adjust() call best reduces overlap by increasing vertical space and adding some horizontal space?

hard

A. plt.subplots_adjust(wspace=1.5, hspace=0.0)

B. plt.subplots_adjust(wspace=0.0, hspace=0.0)

C. plt.subplots_adjust(wspace=0.0, hspace=1.5)

D. plt.subplots_adjust(wspace=0.4, hspace=0.6)

Solution

1. Step 1: Understand the problem of overlapping x-axis labels

   Overlapping x-axis labels usually happen vertically between rows, so increasing vertical space (hspace) helps.

2. Step 2: Consider horizontal space

   Adding some horizontal space (wspace) also improves readability between columns.

3. Step 3: Evaluate options

   plt.subplots_adjust(wspace=0.4, hspace=0.6) increases both wspace and hspace moderately, which best reduces overlap without wasting space.

4. Final Answer:

   plt.subplots_adjust(wspace=0.4, hspace=0.6) -> Option D

5. Quick Check:

   Increase hspace and wspace moderately to reduce overlap [OK]

Hint: Increase hspace for vertical gaps, wspace for horizontal gaps [OK]

Common Mistakes:

• Setting spacing to zero causing overlap
• Increasing only one spacing dimension
• Using too large spacing causing wasted space