Colorbar formatting in Matplotlib - Mini Project: Build & Apply

Colorbar formatting

📖 Scenario: You are working with a heatmap to visualize temperature data across a city grid. You want to add a colorbar to your heatmap to help viewers understand the temperature scale.

🎯 Goal: Create a heatmap using matplotlib and add a colorbar with customized formatting to clearly show the temperature scale.

📋 What You'll Learn

Create a 2D list called temperature_data with exact values

Create a matplotlib figure and axis

Plot the heatmap using imshow with temperature_data

Add a colorbar to the heatmap and format its label and ticks

Print the colorbar's label text to confirm formatting

💡 Why This Matters

🌍 Real World

Colorbars help people understand the meaning of colors in heatmaps or other visualizations, such as temperature maps or population density maps.

💼 Career

Data scientists and analysts often customize colorbars to make their visualizations clearer and more professional for reports and presentations.

1

Create the temperature data

Create a 2D list called temperature_data with these exact values: [[22, 24, 23], [25, 27, 26], [24, 23, 22]]

Matplotlib

# Create the temperature_data list with the exact values
# Your code here

Need a hint?

Use square brackets to create a list of lists with the exact numbers.

2

Set up the plot

Import matplotlib.pyplot as plt. Create a figure and axis using plt.subplots().

Matplotlib

temperature_data = [[22, 24, 23], [25, 27, 26], [24, 23, 22]]
# Import matplotlib.pyplot as plt and create figure and axis
# Your code here

Need a hint?

Use import matplotlib.pyplot as plt and then fig, ax = plt.subplots().

3

Plot heatmap and add colorbar

Use ax.imshow(temperature_data) to plot the heatmap. Then add a colorbar with fig.colorbar() and assign it to cbar. Set the colorbar label to 'Temperature (°C)' and set the label font size to 12.

Matplotlib

import matplotlib.pyplot as plt

temperature_data = [[22, 24, 23], [25, 27, 26], [24, 23, 22]]

fig, ax = plt.subplots()
# Plot heatmap and add colorbar with label and font size
# Your code here

Need a hint?

Use ax.imshow() to plot, then fig.colorbar() to add the colorbar. Use cbar.set_label() to set the label and font size.

4

Display the plot and print colorbar label

Print the colorbar label text using print(cbar.ax.yaxis.label.get_text()). Then display the plot with plt.show().

Matplotlib

import matplotlib.pyplot as plt

temperature_data = [[22, 24, 23], [25, 27, 26], [24, 23, 22]]

fig, ax = plt.subplots()

heatmap = ax.imshow(temperature_data)
cbar = fig.colorbar(heatmap)
cbar.set_label('Temperature (°C)', fontsize=12)
# Print the colorbar label text and show the plot
# Your code here

Need a hint?

Use print(cbar.ax.yaxis.label.get_text()) to print the label text, then plt.show() to display the plot.