Parliament Chart
Arranges dots in a hemicycle to show seat distributions in a legislative body, with color encoding party affiliation.
Parliamentary Seat Distribution
460 total seats after general election
View data (7 rows)
| Seats | Party |
|---|---|
| 120 | Left |
| 85 | Center-Left |
| 62 | Center |
| 95 | Right |
| 50 | Nationalists |
| 38 | Greens |
| 10 | Ind. |
Use a parliament chart when…
- Visualizing seat distributions in parliaments or assemblies
- Showing proportional representation in a familiar political format
Avoid when…
- When the data is not about discrete seats or votes
- When precise numeric comparisons are needed
Data it needs
| Property | Value |
|---|---|
| Min Rows | 2 |
| Min Columns | 2 |
| Column Types | stringnumber |
Visual anatomy
Guiding principles
- PerceptionThe Encoding Hierarchy
Group seats by party in contiguous arcs
- PerceptionPreattentive Processing
Order parties left-to-right by political spectrum (preferred) or by size when spectrum is unknown
- PerceptionGestalt Grouping
Annotate the majority line (50% + 1 seat) when the chart's purpose is to show whether a coalition crosses it
Consider instead
Common mistakes
Not grouping seats by party in the hemicycle
Using too many colors for small parties - merge into 'Other'
History
Parliament charts became popular in European political visualization, inspired by the physical layout of hemicycle legislatures.
Accessibility notes
List party names and seat counts in text; don't rely solely on color.
Related reading
Got data? Let's see what works.
Drop your CSV. You'll get a Parliament Chart plus four alternatives - ranked by which one actually fits your data best.