Path simplification in Matplotlib - Mini Project: Build & Apply

Path Simplification with Matplotlib

📖 Scenario: Imagine you have a GPS device that records your walking path as many points. Sometimes, the path has too many points, making it hard to analyze or draw. We want to simplify this path by reducing the number of points while keeping the shape similar.

🎯 Goal: You will create a list of points representing a path, set a tolerance level for simplification, apply path simplification using Matplotlib's Path object, and finally display the simplified path.

📋 What You'll Learn

Create a list of 2D points representing a path

Set a tolerance value for path simplification

Use Matplotlib's Path.simplify_threshold method to simplify the path

Plot the original and simplified paths using Matplotlib

💡 Why This Matters

🌍 Real World

GPS devices and mapping software often record many points. Simplifying paths helps reduce data size and speeds up rendering on maps.

💼 Career

Data scientists and GIS analysts use path simplification to clean and analyze spatial data efficiently.

1

Create the path points

Create a list called points with these exact 2D points: (0, 0), (1, 2), (2, 4), (3, 6), (4, 8), (5, 10), (6, 12), (7, 14), (8, 16), (9, 18).

Matplotlib

# Create the list of points representing the path
# Your code here

Need a hint?

Use a Python list with tuples for each point. Example: [(x1, y1), (x2, y2), ...]

2

Set the simplification tolerance

Create a variable called tolerance and set it to 1.0 to control how much the path will be simplified.

Matplotlib

points = [(0, 0), (1, 2), (2, 4), (3, 6), (4, 8), (5, 10), (6, 12), (7, 14), (8, 16), (9, 18)]
# Set the tolerance value for path simplification
# Your code here

Need a hint?

The tolerance is a float number that controls how much the path is simplified. Smaller means less simplification.

3

Simplify the path using Matplotlib

Import Path from matplotlib.path. Create a Path object called original_path using the points list. Then create a simplified path called simple_path by calling original_path.simplify_threshold(tolerance).

Matplotlib

points = [(0, 0), (1, 2), (2, 4), (3, 6), (4, 8), (5, 10), (6, 12), (7, 14), (8, 16), (9, 18)]
tolerance = 1.0
# Import Path and create original_path and simple_path
# Your code here

Need a hint?

Use Path(points) to create the path and simplify_threshold(tolerance) to simplify it.

4

Plot the original and simplified paths

Import matplotlib.pyplot as plt. Plot the original path points as a blue line and the simplified path points as a red line with circle markers. Use plt.show() to display the plot.

Matplotlib

from matplotlib.path import Path

points = [(0, 0), (1, 2), (2, 4), (3, 6), (4, 8), (5, 10), (6, 12), (7, 14), (8, 16), (9, 18)]
tolerance = 1.0

original_path = Path(points)
simple_path = original_path.simplify_threshold(tolerance)
# Import matplotlib.pyplot as plt and plot both paths
# Your code here

Need a hint?

Use plt.plot() twice: once for original path with a blue line, once for simplified path with red circles connected by lines. Add labels and show the plot.