Sadly, you can no longer see the full version on Khan Academy.

https://khanacademy.zendesk.com/hc/en-us/articles/203353750-Where-is-the-Knowledge-Map-Star-Map-math-overview-

The Exercise Dashboard is not as helpful for highlighting dependencies: https://www.khanacademy.org/exercisedashboard

You may be able to find other knowledge maps; Khan wasn't the first to have the idea. I like Kaj's idea as well. I compared the curricula of several majors at MIT to come up with a core curriculum, useful across engineering, computer science, and biology.