Psychogeographical Markup Language
As socialfiction's explanation
As socialfiction's explanation puts it, it's kind of a way for a bunch of people walking around to assemble non-geographic maps that reflect how people feel about the urban fabric at a given location. Old-school analogue is Kevin Lynch's mental model, as in Image of the City.
Or, looked at another (cooler) way, it's the cheat code for a city. You know, like in Doom, when you type IDDQD and become invulnerable? Oh, come on, people -- all the kids are playing the "computer games." You should check it out.
Very nifty are the different metadata tags that PML allows for a given space. Check it:
Places can be perceived as:
Distinct (when a place is distinct in any way from the surroundings)
Open (the node present itself as welcoming, it seems to invite your entrance)
Close (the node present itself as not welcome to visitors)
Lively (a place seems evolving, a centre for social interaction)
Ease (a place where you feel at ease, a friendly atmosphere, positive vibes, etc)
Desolate (a feeling of being at loss)
Hectic (too many sensory perceptions)
Terror (a place that 'expands the soul, and awakens the faculties to a high degree of live')
Horror (a place that 'contracts, freezes, and nearly annihilates' the soul)
Stim (a point of stimulation)
Dross (a space that is ignored, a wasted space)
Colour (instead of tagging with words, this tag allows for classification using your own colour-coding system)
How we feel about our cities and how we record/track/codify/encode our cities should not be separate.