Carte figurative relative au choix de l'emplacement d'un nouvel Hotel des Postes de Paris
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
It replaces an argument about where with a single measurable criterion - minimum total distance travelled by the mail - and then prints the entire calculation on the same sheet as the conclusion, so the reader can audit it rather than trust it. Area-scaled black squares over tinted districts give an instant ranking of demand while the printed numbers keep the claim falsifiable, which is the whole rhetorical trick: the graphic persuades and the figures defend. Putting the prose brief in the margin instead of in a separate memo means the recommendation and its evidence can never be separated in circulation.
Steal this when
Reach for this when you are recommending a location, an allocation or a threshold and you expect the decision to be made politically rather than on merit. Put the decision rule, the weighted data and the recommendation on one page so anyone who wants to overrule you has to argue with the arithmetic in front of witnesses.