Analysis of the map as historical place

I wish for a second, before I delve into my research on the Rideau Canal and the relationship of geography and history, to relate a final observation that was crucial to my thinking of my pictures of the map on my Ipad.
To recall:

When I reviewed my photographs that evening, I was a little disappointed and frustrated that there was a glare of the buildings behind on the map. Then I realized it was terribly poetic to have the buildings of the university, and the trees that were purposely planted superimposed onto the map in such a manner. It was a visual metaphor of everything I had been thinking - My understanding of historical place was linked to the legacy of geography and the repeated 'superimposing' of colonies, peoples, roads, and yes canals in the natural landscape. We see all of the layers in one single image - the earth, the greenery, then the roads, the little 'points of interest', the paths marked in yellow (suspiciously like a highlighter of what's important to see), and finally the place in which we come to see such a map - the wider site in which it stands, the buildings, the trees, the sun, the people, the city, and my own figure in the present.
What then, does the map 'say' in the discursive sense about the historical positioning of the Rideau Canal?