A person walking through a street produces an experience, not a statistical portrait of that street. The distinction matters because urban descriptions frequently jump from a situated encounter to a general proposition about a public space. A bench occupied at midday is not evidence that a square is always welcoming; an empty path is not proof of fear; a lively café terrace does not establish social inclusion. Yet repeated bodily encounters can become valuable public evidence when their circumstances remain visible. Route, hour, weather, duration, observer, activity and environmental condition form part of the observation rather than background information to discard. The passage from body to street, from street to park and from park to neighbourhood is therefore a question of evidential scale: what additional relations must be established before an individual trace can support a wider claim? Walking, photography, behavioural observation, video, shade and sound records can be compared without assuming that all of them measure the same phenomenon. A route describes exposure; a photograph records a configuration; a count addresses a bounded occurrence; a conversation reveals situated interpretation. Projects such as WalkableWisdom and HOODKNOWS suggest how these different records might be related within a shared field of inquiry. The ambition is not to transform walkers into anonymous sensors, but to preserve their positionality while allowing observations to become inspectable and comparable. Public space begins to enter research when individual traces can be related to places and times without being mistaken for the whole population that uses them.
