'P' is the key

[eggyk]

I think we run into the same issue though, because yes, it says size of parchment size of map- but again, how does one determine what parts are a map without knowing the contents beyond the box? I see the logic for "map, rectangle" don't get me wrong, but I just dont know how one would apply a uniform measurement to that in a way that is non-speculative. 

Even the JSTOR literature uses a variety of the terms that create some ambiguity: parchment, vellum, and map. Vellum and parchment are different materials. 

Anyway, I think my argument is still there's lexical ambiguity.

The map is the part contained within the the box + the box itself. Library of congress have chosen to not include the ~4cm of embellishments at the top as part of the map, while the article includes it. 

Its not really that speculative. The map is the map, the ship is the ship, and the text is the text. It's quite nicely seperated. 

In every case, the distance from the top to the bottom of the page is either 28cm or 29cm.