I realize I am now posting this post-walking, but I will try to be fair and post what our original "clue" was on the city prior to sleuthing:
We are automatons in an unfamiliar cityscape, "rovers" sent from the red planet to discover the order of this green land. This is our directive from the totalizing eye, the solar god, the voyeur from on high who wishes to know all.
Given the city as a an ecosystem, and human inhabitants as its protagonists/antagonists, what is the nature of their interaction with the ecosystem, specifically the connective, collective tissue that is moderated by the city's governing body: public land? The question is simplified by acquiring a binary data set: boundary or no boundary. Where we are able to walk and 'trespass' upon their open land, we move quickly. Where we see open space, but cannot access it, we walk slowly, and we inspect closely the barrier which denies our access. We ask questions with our rasterizing devices, to let loose our hound-dog pixels to carve out the qualities of the barrier's thickness or thinness, vegetated or dead surface, transparency or opacity. In this way we might glean some understanding of how these earthlings live about their collectively owned spaces.