Charts & Visualizations
Chord Diagram
A circular visualization showing relationships between entities through arcs and curves.
Definition
Chord diagrams visualize relationships or flows between a set of entities arranged radially around a circle. Connections between entities are shown as arcs (chords) inside the circle. The thickness of the chord often represents the magnitude of the flow or relationship between the two connected entities.
Examples
Migration flows between regions A, B, and C
Chart Visualization
This example includes an interactive chart visualization with 4 data points.
Chart type: chord
Usage
Best Used For
- Visualizing relationship matrices or flow data between distinct groups
- Showing bidirectional flows or co-occurrence patterns
- Comparing the strength of connections between entities
- Displaying network connectivity in a compact, circular format
Data Requirements
[Object]
Limitations
Important Considerations
- ⚠Can become cluttered with many entities or dense connections
- ⚠Difficult to interpret exact values from chord thickness alone
- ⚠Less intuitive for audiences unfamiliar with the format
- ⚠Labeling entities around the circle can be challenging with many segments
Best Used For
- Visualizing relationship matrices or flow data between distinct groups
- Showing bidirectional flows or co-occurrence patterns
- Comparing the strength of connections between entities
- Displaying network connectivity in a compact, circular format
Frequently asked questions
Common questions about Chord Diagram, answered.
What is a chord diagram?
A chord diagram places a set of entities around the circumference of a circle and draws curved ribbons (chords) between them to represent relationships or flows, where the thickness of each ribbon encodes the magnitude of the connection. It's well suited to showing how a fixed set of categories relate or exchange with one another — migration between regions, transfers between accounts, or co-occurrence between tags.
When should I use a chord diagram?
Use one to show the relationships or flows among a defined, smallish set of categories (roughly up to 10–12) where the connections between them are the focus and the layout's symmetry helps. Good cases include channel-to-channel attribution overlap, cross-sell between product categories, or movement between states. Avoid it for many categories (the ribbons become an unreadable knot) or when you simply need to rank values (use a bar chart).
Chord diagram vs Sankey diagram — what's the difference?
Both show flows with ribbon thickness encoding magnitude, but the layout differs. A chord diagram is circular and best for relationships among a single set of categories, including bidirectional ones (A↔B). A Sankey is linear and best for directional flow through stages from sources to destinations (A→B→C). Use a chord diagram for relationships within one group; use a Sankey for multi-stage directional flow.
How do I keep a chord diagram readable?
Limit the number of categories (around 10–12 max), order them around the circle meaningfully (by group or size) rather than randomly, color ribbons by source or category, and use interactivity — highlighting one category's chords on hover — to cut through the overlap. If you have too many categories or the ribbons still tangle, aggregate small ones or switch to a matrix heat map of the relationships.
What does ribbon thickness represent in a chord diagram?
Ribbon (chord) thickness encodes the magnitude of the connection between two entities — the volume of flow, number of interactions, or strength of the relationship. Where a ribbon meets each entity's arc, its width reflects that entity's share of the connection, and the total arc length for an entity reflects its overall involvement. As always, include a note or legend, since these encodings aren't self-explanatory.
