Carte figurative et approximative des tonnages des grands ports et des principales rivieres d'Europe
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
Two encodings share the sheet without competing because they attach to different things: proportional-area circles for points, proportional-width bands for lines, and each carries its own number printed inside so the reader is never forced to judge area by eye alone. Minard states in the legend that he deliberately distorted the geography, which converts what looks like an error into a declared method and lets the sheet be read as a diagram rather than a map. The cut-off at 200,000 tonnes is printed rather than hidden, so the editing becomes part of the argument instead of a weakness in it.
Steal this when
When the real layout, a map, an org chart, a market structure, is crowding out the quantity you need people to see, stretch the layout to fit the data and say in the legend that you did.