Radial Bar Chart
Source: Data Visualisation Catalogue - Radial Bar Chart
Why This Belongs In The Compiler Gallery
Radial bar charts reuse the direct generated-path surface added for polar charts, but they encode values as sweep length along concentric tracks rather than radial sector height.
Data Contract
Each raw row is one ordered category value.
| Field | Type | Purpose |
|---|---|---|
channel | categorical | Bar category and legend key. |
value | quantitative | Quantity encoded by arc sweep. |
pathD | text, derived | Generated annular value arc path. |
trackPathD | text, derived | Generated full-track annular path. |
innerRadius, outerRadius | quantitative, derived | Ring placement. |
endAngle | quantitative, derived | Value-derived sweep endpoint. |
Compiler Mapping
| Compiler part | Mapping |
|---|---|
| Data source | channel-progress raw rows and derived radial-bars. |
| Transform | layout with layoutKind: "radialBars". |
| Scales | color: ordinal(channel). |
| Layers | Context track paths, value arc paths, labels, and color legend. |
| Guides | Generated track rings and value labels. |
Faithfulness Notes
The compiler now owns radial-bar track and arc geometry. Remaining work is polar-axis guide generation, richer start/end angle presets, and label collision handling for dense or small arcs.