Pie & donut encodes values as angle (and area) of a circle slice. Playfair 1801; Florence Nightingale’s coxcomb is a polar cousin, 1858.
In reports, ads and assignments it fits two to five parts that sum to a meaningful whole. Skip it when many similar slices, 3-D pie, or comparing two pies.
Parts
- Mark — The core mark of Pie & donut is angle (and area) of a circle slice.
- Scale — The scale must show zero (or a declared break) and units.
- Axis — Axis titles name the variable, not a mood.
- Legend — A legend is weaker than a direct label. Write beside the mark when you can.
- Label — Numbers are optional. If comparison is the job, label the ends only.
- Grid — Keep the grid faint. Data should own the ink.
- Annotation — One annotation sentence. Date the source.
- Frame — A thin frame. Never a 3-D box.
Variants
- Pie chart — Variant 1 of Pie & donut. Same encoding, different layout.
- Donut chart — Variant 2 of Pie & donut. Same encoding, different layout.
- Part-to-whole — Variant 3 of Pie & donut. Same encoding, different layout.
- Pie & donut 4 — Variant 4 of Pie & donut. Same encoding, different layout.
Labels
- Axis — On Pie & donut, make Mark readable.
- Legend — On Pie & donut, make Scale readable.
- Label — On Pie & donut, make Axis readable.
- Grid — On Pie & donut, make Legend readable.
- Annotation — On Pie & donut, make Label readable.
Pie & donut: honour angle (and area) of a circle slice, and switch when many similar slices, 3-D pie, or comparing two pies.