Very nice map.

Historical comment only. I first listened to this music in the late 1970s. One big change in the story, over time, is how few people trace the sound to Hendrix now. (Not this map in particular. Metal fans I know would agree with the map.) I think (?) a common current viewpoint is that Led Zep [!?] was foundational but the genre really started with Black Sabbath and Judas Priest.

Which, definitions change. But in 1977 I listened to Purple Haze and, sure, it was "Psychedelic Rock" as indicated on the map. 100%! But it was also almost definitionally metal. Forty-nine years ago, I mean, not today.

[!?] I love Zeppelin. But I would have been laughed out of high school if I'd compared them to metal, or claimed they were even hard rock.