Album de statistique graphique de la Ville de Paris - sheet 5 of 12 (BnF btv1b52505495j)
The pattern
This still is filed under Data as proof.
Define
A chart, map, or count that is the argument, not an illustration next to the argument.
Mechanism
Sighted evidence. The reader is asked to believe their eyes: a bar, a share, a spread on a map.
Verdict
The claim is comparative or quantitative and the figure can be read without a caption doing the sell.
Why it works
Position is given away to geography and is therefore not available for quantity, so the sheet uses circle area for magnitude and sector angle for composition, which is the only combination that leaves the map legible. The oversized total circle solves the range problem head on: instead of compressing everything to fit the largest value, it declares a second, stated scale and keeps the small gates readable. Printing the exact figure in red under each circle admits that area is a poor quantity channel and repairs it with a number. The colour table is built as swatch, name and leader line, so a reader matches a slice to a class of goods without leaving the plate.
Steal this when
Reach for this when the question is not just how big each location is but what each location is made of, and the locations have to stay in their real positions. The two-scale trick, one for the parts and a declared larger one for the whole, is worth copying whenever a single total would otherwise flatten every detail.