Dealing with a large map is often troublesome. They get torn and wrinkeled and caught by the wind, or you just don’t have the space to unfold them.
About 15 years ago I came across a map that was folded and cut in such a way that even though it was about 1.5m x 1.5m, it unfolded to no more than magazine size.
I am trying to reverse engineer the design here.
If the first page was left a little wider than the rest, this might also be handy to look up values in a very large table and still be able to see the row and column headers, much like the Excel split frame function.
More: continued here