When should I use a chord diagram?

Showing mutual flows between a small set of entities ● Highlighting strongest bilateral relationships

When should I avoid a chord diagram?

When there are more than 10-12 entities ● When flows are unidirectional (use Sankey instead)

What are common mistakes with chord diagrams?

Overloading with too many groups making arcs unreadable ● Not sorting arcs to reduce visual crossings

Flow

Chord Diagram

Displays flows between entities arranged in a circle, with arc widths encoding volume of bidirectional relationships.

Inter-Continental Trade Flow

Bilateral trade volume between regions

View data (8 rows)

Chart data table: Inter-Continental Trade Flow
value	source	target
45	Asia	Europe
30	Asia	Americas
25	Europe	Americas
15	Europe	Africa
20	Americas	Asia
10	Africa	Europe
8	Africa	Asia
12	Americas	Africa

Make a chord diagram with your data

Use a chord diagram when…

Showing mutual flows between a small set of entities
Highlighting strongest bilateral relationships

Avoid when…

When there are more than 10-12 entities
When flows are unidirectional (use Sankey instead)

Data it needs

Property	Value
Min Rows	4
Min Columns	3
Column Types	stringstringnumber

Visual anatomy

Marks

arcribbon

Channels

arc length (total flow)ribbon width (pairwise flow)color (entity)

Axes

Guiding principles

Consider instead

Sankey Diagram

When flow direction matters and there are clear stages

Network Graph

When topology matters more than flow volume

Common mistakes

Overloading with too many groups making arcs unreadable
Not sorting arcs to reduce visual crossings

History

Popularized for genomics by Krzywinski's Circos plots (2009) and for migration matrices in 2010s data journalism via D3.js.

Accessibility notes

Provide a matrix table of pairwise flows as a text alternative.

Got data? Let's see what works.

Drop your CSV. You'll get a Chord Diagram plus four alternatives - ranked by which one actually fits your data best.

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