This is old news, but do check out Ward Shelley's website. This is real map art. Take a closer look at his History of Science Fiction. The genre emerges from the left far in the past rooted in fear and wonder with help from art and philosophy. The big orange-lined cloud further to the right and later in time is the Enlightment, giving rise to science, utopias, AND the anti-rational moving on to the romantic movement.
I'm really impressed by the "holes" in the page where some tentacles leave the map to enter other territories… Edgar Allen Poe starts a green branch all his own which eventually exits below the big blue Star Wars/Star Trek blob-tentacle.
One may not agree with all his categories, but what I especially like is the coming together of all these different fields to create an entirely new genre…the not-entirely parallel time streams technique! What an esthetic…