Visitors.Files is a neat project in between art and information visualization by Christina Ray.

Christina Ray's Visitor.Files originated with a wish to replicate the heightened awareness commonly felt when first landing in a foreign city, when every person, sight and smell appears curious and full of potential. By including herself in the common flow of sidewalk activity and intensely studying the events happening around her,

The making of the visualization is of particular interest:

The Visitor.Files process involves acting as a passive observer of the activity at street intersections. At the locations she visits, Ray takes notes, shoots video and photographs and collects "samples" such as flyers, newspapers or other urban detritus. Each session of overt surveillance lasts approximately 15 minutes, or until 25 specific activities have been noted. Observations are tied to the date, time, weather, location and direction (i.e. "Woman in a red coat walking a large dog walks west, then south" or "police car stops at light, then goes north"). The information collected is entered into a database which then informs a series of coded maps. These "maps" in turn become geometric abstract paintings on vellum that simultaneously resonate with random activity and systemic order. The paintings, photographs, samples and video footage are gathered into slim file cases, one for each session, to literally encapsulate the original experience and the multiplicity of the data collection.

There is also a blog about it, with great pictures.