About Chord Diagram Generator

Create chord diagrams to visualize connections between entities. Part of the DevTools Surf developer suite. Browse more tools in the Data / SQL collection.

Use Cases

• Visualize inter-team communication frequency from meeting data
• Display trade flow volumes between countries or economic regions
• Show cross-referencing patterns between document sections or modules
• Represent migration or population movement between cities or regions

Tips

• The input is a symmetric matrix — the value at row i, column j represents the flow magnitude from entity i to entity j
• Use the arc thickness to encode total flow volume per entity: thicker arcs indicate higher aggregate activity
• Sort entities by total flow (descending) to put the most interconnected nodes at the top of the chord diagram

Fun Facts

• Chord diagrams were first used in biology to visualize chromosomal rearrangements — specifically translocations between chromosomes in cancer genomics. The Circos tool (2009) popularized this visualization format for genomic data.
• The New York Times used chord diagrams in 2010 to visualize international migration flows between countries — bringing the format to mainstream data journalism and making it one of the most recognized complex visualizations in news media.
• A fully connected chord diagram with n entities has n*(n-1)/2 chords. For 10 entities that is 45 chords — the point at which visual clutter typically overwhelms insight, making filtering or highlighting essential.

FAQ

What is the difference between a chord diagram and a Sankey diagram?

Sankey diagrams show directional flow from source to destination, with nodes in a linear layout. Chord diagrams show bidirectional relationships between entities arranged in a circle, emphasizing mutual exchange rather than directional flow.

What data format does the input require?

A square matrix (CSV or JSON) where each cell [i][j] contains the flow value from entity i to entity j. The diagonal is typically 0. The tool also accepts an edge list format (source, target, value).

When is a chord diagram not appropriate?

When the relationships are directional and asymmetric (use Sankey), when there are more than 15-20 entities (use a heatmap or network graph), or when precise value comparison matters more than pattern recognition (use a matrix chart).