Figure size for publication in Matplotlib - Mini Project: Build & Apply

Figure size for publication

📖 Scenario: You are preparing a graph to include in a scientific paper. The journal requires figures to be exactly 6 inches wide and 4 inches tall for consistent formatting.

🎯 Goal: Create a matplotlib plot with the exact figure size required by the journal, then display a simple line plot.

📋 What You'll Learn

Create a figure with size 6 inches wide and 4 inches tall using matplotlib

Plot a simple line graph with points (1, 1), (2, 4), (3, 9)

Display the plot

💡 Why This Matters

🌍 Real World

Researchers and scientists often need to prepare figures that fit exact size requirements for journals or presentations.

💼 Career

Knowing how to control figure size and create clear plots is essential for data scientists and analysts who share visual results.

1

Create the data points

Create two lists called x and y with values [1, 2, 3] and [1, 4, 9] respectively.

Matplotlib

# Create lists x and y with the given values
# Your code here

Hint

Use square brackets to create lists. For example, x = [1, 2, 3].

2

Set the figure size

Import matplotlib.pyplot as plt and create a figure with size 6 inches wide and 4 inches tall using plt.figure(figsize=(6, 4)).

Matplotlib

x = [1, 2, 3]
y = [1, 4, 9]

# Import matplotlib.pyplot as plt and create a figure with size (6, 4)
# Your code here

Hint

Use import matplotlib.pyplot as plt to import, then plt.figure(figsize=(6, 4)) to set size.

3

Plot the line graph

Use plt.plot(x, y) to plot the line graph with the data points.

Matplotlib

import matplotlib.pyplot as plt

x = [1, 2, 3]
y = [1, 4, 9]

plt.figure(figsize=(6, 4))

# Plot the line graph using plt.plot(x, y)
# Your code here

Hint

Use plt.plot(x, y) to draw the line connecting the points.

4

Display the plot

Use plt.show() to display the plot on the screen.

Matplotlib

import matplotlib.pyplot as plt

x = [1, 2, 3]
y = [1, 4, 9]

plt.figure(figsize=(6, 4))
plt.plot(x, y)

# Display the plot using plt.show()
# Your code here

Hint

Call plt.show() to open the plot window.

Practice

1. What does the figsize parameter control in a matplotlib figure?

easy

A. The font size of the labels

B. The width and height of the figure in inches

C. The color of the figure background

D. The style of the plot lines

Solution

1. Step 1: Understand the role of figsize

   The figsize parameter sets the size of the entire figure in inches, controlling width and height.

2. Step 2: Differentiate from other parameters

   Other parameters like color or font size do not affect figure size but appearance details.

3. Final Answer:

   The width and height of the figure in inches -> Option B

4. Quick Check:

   Figure size = width and height in inches [OK]

Hint: Remember figsize sets width and height in inches [OK]

Common Mistakes:

• Confusing figsize with color or font size
• Thinking figsize controls plot line style
• Assuming figsize is in pixels

2. Which of the following is the correct way to set a figure size of 8 inches wide and 4 inches tall in matplotlib?

easy

A. plt.figure(size=[8, 4])

B. plt.figure(size=(8, 4))

C. plt.figure(width=8, height=4)

D. plt.figure(figsize=(8, 4))

Solution

1. Step 1: Recall correct parameter name and type

   The parameter to set figure size is figsize and it expects a tuple (width, height).

2. Step 2: Check syntax correctness

   plt.figure(figsize=(8, 4)) uses figsize=(8, 4) which is correct syntax. Using size causes TypeError (unexpected keyword). Using width=8, height=4 also causes TypeError (no such parameters).

3. Final Answer:

   plt.figure(figsize=(8, 4)) -> Option D

4. Quick Check:

   Use figsize=(width, height) tuple [OK]

Hint: Use figsize=(width, height) tuple in plt.figure() [OK]

Common Mistakes:

• Using 'size' instead of 'figsize'
• Using separate width and height parameters
• Forgetting parentheses around figsize values

3. What will be the size of the figure in inches after running this code?

import matplotlib.pyplot as plt
plt.figure(figsize=(6, 3))
plt.plot([1, 2, 3], [4, 5, 6])
plt.show()

medium

A. 6 inches wide and 3 inches tall

B. 3 inches wide and 6 inches tall

C. Default size (usually 6.4 x 4.8 inches)

D. Cannot determine without dpi

Solution

1. Step 1: Identify figsize parameter values

   The code sets figsize=(6, 3), which means width=6 inches and height=3 inches.

2. Step 2: Understand effect on figure size

   This directly sets the figure size regardless of dpi, so the figure will be 6 inches wide and 3 inches tall.

3. Final Answer:

   6 inches wide and 3 inches tall -> Option A

4. Quick Check:

   figsize=(6, 3) means width=6, height=3 inches [OK]

Hint: figsize=(width, height) sets exact figure size in inches [OK]

Common Mistakes:

• Swapping width and height values
• Thinking dpi affects figsize dimensions
• Assuming default size if figsize is set

4. Identify the error in this code that tries to set figure size:

import matplotlib.pyplot as plt
plt.figure(figsize=8, 4)
plt.plot([1, 2], [3, 4])
plt.show()

medium

A. No error, code runs fine

B. plt.plot syntax is incorrect

C. figsize should be a tuple, not two separate arguments

D. plt.show() is missing parentheses

Solution

1. Step 1: Check figsize parameter usage

   The code uses figsize=8, 4 which passes two separate arguments instead of a single tuple.

2. Step 2: Understand correct figsize syntax

   Correct syntax requires a tuple: figsize=(8, 4). Without parentheses, it causes a TypeError.

3. Final Answer:

   figsize should be a tuple, not two separate arguments -> Option C

4. Quick Check:

   figsize=(width, height) needs parentheses [OK]

Hint: Always use parentheses for figsize tuple [OK]

Common Mistakes:

• Passing figsize values without parentheses
• Confusing plt.plot syntax errors
• Forgetting plt.show() parentheses (not the case here)

5. You want to create a publication-ready plot with a width of 7 inches and height of 5 inches. You also want to save it as a PNG file with 300 dpi resolution. Which code snippet correctly sets the figure size and saves the plot?

hard

A. plt.figure(figsize=(7, 5))
plt.plot(data)
plt.savefig('plot.png', dpi=300)

B. plt.figure(size=(7, 5))
plt.plot(data)
plt.savefig('plot.png', dpi=300)

C. plt.figure(figsize=[7, 5])
plt.plot(data)
plt.savefig('plot.png')

D. plt.figure(figsize=(7, 5))
plt.plot(data)
plt.save('plot.png', dpi=300)

Solution

1. Step 1: Set figure size correctly

   Use figsize=(7, 5) tuple in plt.figure() to set width and height in inches.

2. Step 2: Save figure with correct dpi and function

   Use plt.savefig('plot.png', dpi=300) to save with 300 dpi resolution. plt.figure(size=(7, 5)) plt.plot(data) plt.savefig('plot.png', dpi=300) uses wrong parameter size. plt.figure(figsize=[7, 5]) plt.plot(data) plt.savefig('plot.png') misses dpi. plt.figure(figsize=(7, 5)) plt.plot(data) plt.save('plot.png', dpi=300) uses wrong function plt.save.

3. Final Answer:

   plt.figure(figsize=(7, 5)) plt.plot(data) plt.savefig('plot.png', dpi=300) -> Option A

4. Quick Check:

   figsize tuple + savefig with dpi=300 [OK]

Hint: Use figsize tuple and savefig with dpi for publication [OK]

Common Mistakes:

• Using 'size' instead of 'figsize'
• Forgetting dpi in savefig for quality
• Using plt.save instead of plt.savefig