How can Pygal be used to visualize a treemap in Python?

Visualizing data is an important step since it helps understand what is going on in the data without actually looking at the complicated working underneath it and performing complicated computations.

Pygal is an open source Python package that helps in the creation of interactive plots, and SVG (Scalar Vector Graphics) images of graphs. SVG refers to dynamically generating animated graphs with the given data. These SVG images of graphs can be used and customized depending on our requirements. The SVG images are highly scalable, hence they can be downloaded in high quality format. These downloaded images can also be embedded to various projects, websites and so on.

These interactive and customized graphs can be created with ease in Pygal. Pygal helps create bar chart, histogram, line plot, and much more.

What is a Treemap?

Treemap is used to represent that kind of data which is nested in nature. It is represented as a rectangle. The size of the map represents the values present in the dataset. Greater the size of the treemap indicates higher the value of the data point.

Installation

Pygal package can be installed using the below command on Windows ?

pip install pygal

Creating a Basic Treemap

Let us understand how Treemap can be created using Pygal ?

import pygal
from pygal.style import Style

# Define custom colors
custom_style = Style(colors=('#E80080', '#404040', '#9BC850', '#E81190'))

# Create treemap with custom styling
treemap = pygal.Treemap(height=400, width=300, style=custom_style)
treemap.title = "Treemap Visualization"

# Add data to the treemap
treemap.add("Group 1", [0.4, 0.5, 0.6, 0.7])
treemap.add("Group 2", [1.2, 1.3, 1.4])
treemap.add("Group 3", [1.5, 1.6, 1.9])
treemap.add("Group 4", [1.8, 1.9, 2.0, 2.1, 2.2])

# Render the treemap (saves as SVG file)
treemap.render_to_file('treemap.svg')
print("Treemap saved as 'treemap.svg'")

Treemap saved as 'treemap.svg'

Key Features of Pygal Treemap

• Custom Styling: Define custom colors using Style class
• Multiple Data Points: Each group can contain multiple values
• Interactive SVG: Generated treemaps are scalable SVG images
• Rectangle Size: Automatically calculated based on data values

Parameters

• height/width: Dimensions of the treemap in pixels
• style: Custom styling including colors and fonts
• title: Main title displayed on the treemap
• add(): Method to add labeled data groups

Conclusion

Pygal treemaps provide an effective way to visualize hierarchical data with rectangle sizes proportional to data values. The SVG output format ensures high-quality, scalable visualizations that can be easily integrated into web applications and documents.