Colorbar configuration in Matplotlib - Mini Project: Build & Apply

Colorbar configuration

📖 Scenario: You are working with a heatmap that shows temperatures across a city grid. You want to add a colorbar to explain the colors to anyone looking at the map.

🎯 Goal: Create a heatmap using matplotlib and add a colorbar with a label and custom ticks to make the map easy to understand.

📋 What You'll Learn

Create a 2D list called temperature_data with the exact values [[20, 22, 23], [21, 24, 25], [19, 20, 22]]

Create a variable called colorbar_label and set it to the string 'Temperature (°C)'

Use matplotlib.pyplot.imshow to display temperature_data as a heatmap

Add a colorbar to the heatmap with the label from colorbar_label

Set the colorbar ticks to exactly [19, 21, 23, 25]

💡 Why This Matters

🌍 Real World

Colorbars help people understand what colors mean in heatmaps, like showing temperature, population density, or elevation on maps.

💼 Career

Data scientists and analysts use colorbars to make visualizations clear and easy to interpret for reports and presentations.

1

Create the temperature data

Create a 2D list called temperature_data with these exact values: [[20, 22, 23], [21, 24, 25], [19, 20, 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. Each inner list is a row of temperatures.

2

Set the colorbar label

Create a variable called colorbar_label and set it to the string 'Temperature (°C)'

Matplotlib

temperature_data = [[20, 22, 23], [21, 24, 25], [19, 20, 22]]
# Create the colorbar_label variable with the exact string
# Your code here

Need a hint?

Use single or double quotes to create the string exactly as shown.

3

Create the heatmap and add a colorbar

Import matplotlib.pyplot as plt. Use plt.imshow to display temperature_data as a heatmap. Then add a colorbar using plt.colorbar() and set its label to colorbar_label.

Matplotlib

temperature_data = [[20, 22, 23], [21, 24, 25], [19, 20, 22]]
colorbar_label = 'Temperature (°C)'
# Import matplotlib.pyplot as plt
# Create the heatmap with plt.imshow
# Add a colorbar and set its label
# Your code here

Need a hint?

Use plt.imshow to show the data and save the result to a variable. Then pass that variable to plt.colorbar(). Use set_label() on the colorbar to add the label.

4

Customize colorbar ticks and show the plot

Set the colorbar ticks to exactly [19, 21, 23, 25] using colorbar.set_ticks(). Then use plt.show() to display the heatmap with the colorbar.

Matplotlib

import matplotlib.pyplot as plt

temperature_data = [[20, 22, 23], [21, 24, 25], [19, 20, 22]]
colorbar_label = 'Temperature (°C)'

heatmap = plt.imshow(temperature_data, cmap='viridis')
colorbar = plt.colorbar(heatmap)
colorbar.set_label(colorbar_label)
# Set the colorbar ticks to [19, 21, 23, 25]
# Show the plot
# Your code here

Need a hint?

Use colorbar.set_ticks([19, 21, 23, 25]) to set the ticks. Then call plt.show() to display the figure.