Nightingale Rose Chart
Source: Data Visualisation Catalogue - Nightingale Rose Chart
Why This Belongs In The Compiler Gallery
Nightingale rose charts test the second polar-sector mode: equal-angle sectors whose radius changes with the value. This is a useful bridge from pie/donut charts toward broader radial chart families.
Data Contract
Each raw row is one category value.
| Field | Type | Purpose |
|---|---|---|
team | categorical | Sector category and legend label. |
value | quantitative | Quantity encoded by sector radius/area. |
pathD | text, derived | Generated radial sector path. |
outerRadius | quantitative, derived | Value-derived sector radius. |
labelX, labelY | quantitative, derived | Value label anchor coordinates. |
Compiler Mapping
| Compiler part | Mapping |
|---|---|
| Data source | team-volume raw rows and derived sectors. |
| Transform | layout with layoutKind: "polarSectors" and layoutMode: "equalAngleRadius". |
| Scales | color: ordinal(team). |
| Layers | Equal-angle path sectors plus value labels. |
| Guides | Generated color legend. |
Faithfulness Notes
The gallery version uses square-root radius scaling inside the layout so sector area tracks the source value. Remaining work is radial grid rings, polar axes, and label collision handling.