Alpha transparency for overlap in Matplotlib - Mini Project: Build & Apply

Alpha Transparency for Overlap

📖 Scenario: You are working with two sets of data points representing two different groups of people attending events. You want to visualize these points on the same scatter plot to see where they overlap.

🎯 Goal: Create a scatter plot with two groups of points using matplotlib. Use alpha transparency to make overlapping points visible.

📋 What You'll Learn

Create two lists of x-coordinates and two lists of y-coordinates for two groups.

Set an alpha transparency value for the scatter points.

Plot both groups on the same scatter plot with different colors.

Display the plot showing overlapping points with transparency.

💡 Why This Matters

🌍 Real World

Visualizing overlapping data points helps in understanding relationships and densities in data, such as customer locations or event attendance.

💼 Career

Data scientists and analysts use transparency in plots to reveal overlapping data patterns clearly, improving data-driven decisions.

1

Create data points for two groups

Create four lists: x1, y1 for the first group and x2, y2 for the second group with these exact values: x1 = [1, 2, 3, 4, 5], y1 = [5, 4, 3, 2, 1], x2 = [3, 4, 5, 6, 7], y2 = [1, 2, 3, 4, 5].

Matplotlib

# Create lists x1, y1, x2, y2 with the exact values
# Your code here

Need a hint?

Use square brackets to create lists with the exact numbers given.

2

Set alpha transparency value

Create a variable called alpha_value and set it to 0.5 to control the transparency of the scatter points.

Matplotlib

x1 = [1, 2, 3, 4, 5]
y1 = [5, 4, 3, 2, 1]
x2 = [3, 4, 5, 6, 7]
y2 = [1, 2, 3, 4, 5]
# Create alpha_value and set it to 0.5
# Your code here

Need a hint?

Use a simple assignment to create the variable alpha_value.

3

Plot scatter points with alpha transparency

Import matplotlib.pyplot as plt. Use plt.scatter to plot the first group with x1, y1, color 'blue', and alpha set to alpha_value. Then plot the second group with x2, y2, color 'red', and alpha set to alpha_value.

Matplotlib

x1 = [1, 2, 3, 4, 5]
y1 = [5, 4, 3, 2, 1]
x2 = [3, 4, 5, 6, 7]
y2 = [1, 2, 3, 4, 5]
alpha_value = 0.5

# Import matplotlib.pyplot as plt
# Plot first group with blue color and alpha_value
# Plot second group with red color and alpha_value
# Your code here

Need a hint?

Use plt.scatter twice with the correct parameters.

4

Display the scatter plot

Use plt.show() to display the scatter plot with overlapping points shown using alpha transparency.

Matplotlib

import matplotlib.pyplot as plt

x1 = [1, 2, 3, 4, 5]
y1 = [5, 4, 3, 2, 1]
x2 = [3, 4, 5, 6, 7]
y2 = [1, 2, 3, 4, 5]
alpha_value = 0.5

plt.scatter(x1, y1, color='blue', alpha=alpha_value)
plt.scatter(x2, y2, color='red', alpha=alpha_value)

# Display the plot
# Your code here

Need a hint?

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