[helij]

It is obvious because that is how you move a big physical map. You pull it towards or away from yourself to view specific area, just like with a mouse. That's how it was done since first maps. It's just obvious to move a big piece of paper on the table that way.

[jackcviers3]

It's not that - it's the inertial glide to a stop that makes it feel like a big piece of paper that was innovative at the time. See my other comment.