Gesellschaft und Wirtschaft: Bildstatistisches Elementarwerk - Römerreich: Produktion [14080.008]
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
Colour carries the taxonomy and shape carries the item, so a reader learns two dimensions from one mark and can scan for a pattern - black clusters in Spain and Britain, green everywhere, blue around the Italian and Aegean workshops - before reading a single label. The element symbols on the mining tags borrow an existing shared notation instead of inventing another arbitrary glyph, which is why those marks need no legend at all. Using an identical base map to the population plate turns the two sheets into a matched pair the reader can hold in mind together. The single arrow marked (China) at the edge admits a trade relationship that lies off the map without distorting the map to include it.
Steal this when
Use this when a distribution has both a location and a type, and a table would force the reader to rebuild the geography in their head. Give the type to colour, the item to shape, and keep the base flat so the marks are the only texture.