Chartdatum

ChartDatum is a term used in charting and data visualization to denote a single data point within a chart. It typically represents the minimal unit of data that can be plotted, labeled, and styled.

A ChartDatum usually contains coordinates or values: an x value and a y value; for time series, x may be a date or timestamp; a numeric y; in some 3D charts, a z value. Additional attributes can include a value, a category or series identifier, a label, color, size, and a tooltip text. Many implementations also include an optional id and a metadata dictionary for arbitrary key-value pairs to support custom rendering or interaction.

In practice, ChartDatum is used by chart rendering engines to compute positions via scales, apply formatting, and manage interactions such as tooltips or highlights. It often corresponds to a row in a data table and can be serialized to formats like JSON for transfer between systems.

Variations exist across libraries. Some APIs treat ChartDatum as an immutable object, others allow mutation. Some support time-based axes with date parsing, while others require pre-normalized numeric coordinates. The concept remains consistent: a unit of data that a chart uses to plot a point and derive visual attributes.

See also: data point, data series, charting library, scale, tooltip.