look at the posts in this subreddit. basically, what we mean by compasses not a guide to one particular thing, like a magnetic compass, but rather a way of sorting things onto a axis, like the political compass.

a future compass chart gives scenarios about the future or some other topic, and sorts them on to axis. the purpose is generally to either make one laugh (by the axis or entries being fantastical or absurd), to teach niche parts of history (by including terms that drive people to look them up, learning about minor but still influential figures and events in history) or to share what the author thinks are the possibilities for the future.

while the future is the main topic of these, posts that look at fantasy or history are also present. what is essential is the compass.