I wish I could find the reference, but some time ago I read an article on diagrams vs maps and it was pointed out that in this time period diagrams were increasingly incorporating map-type features.
To me, the page is a diagram with some map-like features of a symbolic nature. When interpreting symbolism you have to strip down to simplicity. Take for instance the actual walls (as opposed to more natural-looking elements such as possible cliffs and water. What is a wall? A simple answer is a structure to keep things/people in, or for medieval walls, even more likely to keep things/people out. So, without going into my own interpretation which provides an answer, what are these walls keeping out, and why do they surround only portions of the diagram?
To me, the page is a diagram with some map-like features of a symbolic nature. When interpreting symbolism you have to strip down to simplicity. Take for instance the actual walls (as opposed to more natural-looking elements such as possible cliffs and water. What is a wall? A simple answer is a structure to keep things/people in, or for medieval walls, even more likely to keep things/people out. So, without going into my own interpretation which provides an answer, what are these walls keeping out, and why do they surround only portions of the diagram?