About Chord Charts
Chord charts use a circular layout to show connections between source and target dimensions. Commonly used in the travel industry, chord charts are used to show the source and destination of the route traveled and the volume of traffic that passes through.
In other industries, the chart can use source nodes to categorize the target data. For example, the following chart shows the marital status (source data) of hospital patients, categorized by age group (target data).
The circumference is divided into color-coded segments that represent dimension values. They are sized proportionally based on the sum of their incoming values. The largest section has the highest incoming values.
Inside the circle, arc-shaped chords represent connections between dimensions. The thickness of a chord at each end represents the magnitude of a single value where the attached segment is the target. The color of a chord corresponds to the connected segment with the greater output.
Chord chart options
When you create a chord chart, you specify:
- A source column
- A target column
- A numeric value column
If you are using a two-dimensional dive as a source, the first dimension is the source column and the second dimension is the target column.
Labels around the circumference appear in place of a traditional chart legend. However, legend and display settings are available that you can use to change colors and labels, including limiting the number of characters that display in the labels.
Reading a chord chart
Placing a pointer within a chord opens a tooltip that shows the numeric data associated with it. For example, Boston → New York 45 indicates 45 trips occurred from Boston to New York. Or Married → 19–44 1,240 indicates 1,240 patients aged 19 to 44 are married.
Placing a pointer on a segment shows the a breakdown of the numeric data that applies to that segment plus Volume In and Volume Out data. For example:
New Haven → Boston 30
New Haven → New York 42
Volume Out 72
Volume In 0
See also Chart Portlet Options.