Composition
Nightingale Chart
Polar area chart with wedges of equal angle but varying radius, a polar histogram.
Monthly Rainfall
Average precipitation (mm)
View data (12 rows)
| Rainfall | Month |
|---|---|
| 78 | Jan |
| 65 | Feb |
| 52 | Mar |
| 40 | Apr |
| 30 | May |
| 22 | Jun |
| 18 | Jul |
| 25 | Aug |
| 38 | Sep |
| 55 | Oct |
| 68 | Nov |
| 82 | Dec |
Use a nightingale chart when…
- Cyclical data (months, hours)
- When visual impact matters
- Small number of categories
Avoid when…
- Precise comparison (radial distorts area)
- Non-cyclical data
Data it needs
| Property | Value |
|---|---|
| Min Rows | 4 |
| Min Columns | 2 |
| Column Types | stringnumber |
Visual anatomy
Marks
arc
Channels
radiusangle (equal)color-hue
Axes
angular-categorical
Guiding principles
Common mistakes
Reading wedge area as linearly proportional to value (radius varies, so area scales as r²)
Re-sorting cyclical categories by magnitude and losing the cycle
History
Created by Florence Nightingale in 1858 to visualize causes of death in the Crimean War.
Accessibility notes
Provide percentage values as text. Use patterns alongside color.
Related reading
Got data? Let's see what works.
Drop your CSV. You'll get a Nightingale Chart plus four alternatives - ranked by which one actually fits your data best.