So get this. There are these things called radio stations that broadcast music using frequency modulation. They call it “FM radio.” You don’t download or stream the music, and you don’t get to choose what songs you want to hear right away, but sometimes you can call locally and request a song you like. It’s also free to listen to if you have this thing called a “radio.” In exchange, you have to listen to “commercials” sometimes where someone tries to sell you stuff. Seems like a fair exchange.
Anyways, Erin Davis mapped these radio stations and their coverage, based on FCC data. She joined the data with radio-locator.com data, which provides music genre. This allowed for the splits above.
Technology is amazing.