🫧 Day 37: Chord Chart in Python

 

🌸 Day 37: Circular Chord Diagram in Python

On Day 37 of our data visualization journey, we created a true circular Chord Diagram with a soft, Pinterest-inspired aesthetic using Holoviews + Bokeh.

This visualization beautifully captures relationships between creative platforms and inspiration sources all wrapped in a dreamy pastel theme.

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🎯 What We’re Visualizing

Our nodes:

• Pinterest

• Instagram

• Design

• Inspo

Our goal:
To visualize how these platforms and ideas connect and influence each other.

Unlike Sankey diagrams (which show directional flow), this chord diagram:

• Arranges nodes in a circle

• Connects them with curved ribbons

• Highlights relationship strength

• Feels balanced and visually aesthetic

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🛠 Step-by-Step Breakdown

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✅ 1️⃣ Import Required Libraries

import holoviews as hv
from holoviews import opts
import pandas as pd 
import numpy as np 

hv.extension('bokeh')

We use:

• Holoviews → For high-level interactive visualization

• Bokeh backend → For rendering

• Pandas → For structured data

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✅ 2️⃣ Create Relationship Data

links = pd.DataFrame([
 {'source': 'Pinterest', 'target': 'Design', 'value': 10}, 
 {'source': 'Instagram', 'target': 'Design', 'value': 15}, 
 {'source': 'Design', 'target': 'Inspo', 'value': 20}, 
 {'source': 'Inspo', 'target': 'Pinterest', 'value': 5}, 
 {'source': 'Instagram', 'target': 'Inspo', 'value': 12}, 
 {'source': 'Design', 'target': 'Instagram', 'value': 8}, ])

Each row represents:

• source → Starting node

• target → Connected node

• value → Strength of the relationship

The larger the value, the thicker the ribbon.

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✅ 3️⃣ Define the Dreamy Color Palette

colors = ["#E5989B", "#B5838D", "#6D6875", "#DBC1AD"]

Soft pastel tones create:

• Aesthetic appeal

• Pinterest-style vibe

• Visual harmony

Color choices dramatically affect storytelling and today’s goal was elegance.

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✅ 4️⃣ Create the Chord Diagram

chord = hv.Chord(links)

This automatically:

• Detects unique nodes

• Arranges them in a circular layout

• Draws curved connections

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✅ 5️⃣ Apply Styling

chord.opts(
     opts.Chord(
        cmap=colors, edge_cmap=colors, 
        edge_color=hv.dim('source').str(), 
        node_color=hv.dim('index').str(),
        labels='index', label_text_font='serif',
        edge_alpha=0.4, node_size=20,
        width=600, height=600,
        bgcolor='#FAF9F6'
    ) 
)

✨ What This Styling Does:

• cmap → Applies pastel colors

• edge_color → Colors ribbons by source

• node_color → Colors nodes uniquely

• edge_alpha=0.4 → Soft transparent ribbons

• bgcolor='#FAF9F6' → Linen aesthetic background

• label_text_font='serif' → Elegant typography

This transforms a basic network into a brand-ready visualization.

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✅ 6️⃣ Save as Interactive HTML

hv.save(chord, 'chord_chart.html')

This creates an interactive file where you can:

• Hover over connections

• Explore relationship strength

• Zoom and inspect

Perfect for:

• Portfolios

• Presentations

• Websites

• LinkedIn posts

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📊 What the Visualization Reveals

• Instagram strongly influences Design

• Design heavily feeds into Inspiration

• Inspiration loops back to Pinterest

• Design and Instagram have mutual interaction

It visually tells a story of creative content flow.

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💡 Why Chord Diagrams Are Powerful

✔ Show interconnected systems
✔ Perfect for circular relationships
✔ Visually impactful
✔ Great for storytelling
✔ Ideal for brand-driven data aesthetics

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🔥 Real-World Use Cases

• Social media ecosystem analysis

• Marketing channel relationships

• Trade networks

• Collaboration mapping

• Content flow visualization