Chord diagram

Screenshot from "A Thousand Fibers Connect Us — Wikipedia's Global Reach", winning entry of the WikiViz 2011 Data Visualization Challenge. Lines represent readership of different Wikipedia language versions (lower half) from countries (top half)

A chord diagram is a graphical method of displaying the inter-relationships between data in a matrix. The data is arranged radially around a circle with the relationships between the points typically drawn as arcs connecting the data together.

The format can be aesthetically pleasing, making it a popular choice in the world of data visualization.

Name

Chord diagrams get their name from terminology used in geometry. A chord of a circle is a geometric line segment whose endpoints both lie on the circle. Chord diagrams are also known as radial network diagrams and may sometimes be referred to as a type of circular layout.

Hierarchical Edge Bundling

While a small amount of data could be represented in a circular diagram using straight lines to show the interconnections, a diagram featuring numerous lines would quickly become illegible. To reduce the visual complexity, chord diagrams employ a technique called hierarchical edge bundling.^[1]

History

This type of diagram was popularized in 2007 by the New York Times infographic Close-Ups of the Genome^[2]

References

1. Holten, Danny (SEPTEMBER/OCTOBER 2006). "Hierarchical Edge Bundles: Visualization of Adjacency Relations in Hierarchical Data" (PDF). IEEE Transactions on Visualization and Computer Graphics (IEEE Computer Society) 12 (5). ISSN 1077-2626. Check date values in: |date= (help)
2. http://circos.ca/ Ciros

External links

• Hierarchical Edge Bundling is the technique by which the lines connect nodes together are grouped to reduce visual clutter.