The Georgia Negro: A Social Study - Plat shows the location of residences of different classes of African Americans [LCCN2013650364]
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
Plotting at the lot level lets segregation appear as pattern rather than assertion - the reader discovers the clustering themselves, which is far harder to argue with than a stated percentage. The two street grids meeting at an angle give the plate a genuine compositional tension that a regular grid would not, and the green river wash is the only mass of colour, so the dots stay legible at their true tiny size. Switching the key to copperplate script marks it as the surveyor's own annotation, which reads as field evidence rather than design.
Steal this when
Use this when the claim is about distribution rather than totals and any summary number would let the reader off the hook - draw the real geometry, place one mark per unit, and keep every other element pale so the marks carry.