Part of a whole
Rose / polar-area chart
Uses equal-angle sectors with radii chosen so sector area represents magnitude.
- Chart
- Composition
- Cyclic comparison
What it answers
How do magnitudes compare around a cycle?
- Shape
- Equal-angle sectors of varying area
- What it shows
- Cyclic magnitude differences.
Example
The question
Which months bring the most support tickets?
Support tickets by month, 2025 (rose chart; area shows the count)
Illustrative data. It belongs to no company.
When to use it
Use it when
Cyclic categories with an area-proportional design.
Avoid it when
When readers may compare radii as if they were values.
How to read it
Compare equal-angle sector areas and use the radius/value key.
Note
Not a pie chart or a general wind rose.
The data you need
- Layout
- Long table
- Fields
- Sector: ordered category; Value: nonnegative number
- One row is
- One equal-angle sector and its magnitude. What is the grain?
- Rules
- Keep angular sectors equal for an area-proportional rose. Radius must follow the square root of value for equal angles.
- Optional
- Optional Group. Define cyclic ordering.
- Preparation
- Order equal-angle sectors and scale squared radius to magnitude so sector area is proportional to value.
- Units
- Equal-angle sector area is proportional to value; radius follows its square root.
Worked example
Values 1 and 4 in equal-angle sectors require radii in ratio 1:2. The second sector has four times the area.
| Sector | Value |
|---|---|
| Q1 | 30 |
| Q2 | 45 |
| Q3 | 25 |
| Q4 | 40 |