by Doug Allen
Theoretical physicist Dirk Brockmann used data entered on the dollar-bill tracking site wheresgeorge.com to explore boundaries in the US:
Brockmann took data for how the dollar bills traveled, and used network theory to draw lines where dollar bills are less likely to cross. In places they follow state borders, but not always; Missouri is divided into East and West, as is Pennsylvania. The “Chicago catchment area” includes a big chunk of both Indiana and Wisconsin.
The resulting map shows how “effective communities” don’t necessarily follow state lines. “I don’t know so much about the culture of the U.S.,” says Brockmann, who grew up in Germany. “But when I give talks on this, normally someone in the audience says, ‘Oh, this makes perfect sense.”
Update from a reader:
I’d like to point out that the “effective communities” that Mr. Brockmann references in his map may not be as organic as he implies. The boundaries roughly correspond to the districts serviced by the Federal Reserve Banks, which exchange old bills collected by banks for new bills.
(Image from Dirk Brockmann)