

All these fancy answers and I’ll give you a real simple one: sidewalks and paved roads. Does it have fully paved roads and sidewalks? Urban. Does it have that and mostly houses? Suburban. Some/no sidewalks and the roads aren’t all paved or is done poorly? Small town/rural. It’s all about the concrete/asphalt to dirt ratio.
It’s a reference to an actual note someone put up and is basically calling them a giant nerd instead of leaving a normal message like “hey, found wallet, call this number”. Although in fairness, the idea is actually pretty interesting because it creates an easy cypher only the intended recipient can crack, thus filtering out cons.
The original note was almost identical, MINUS the Star Trek part.