Eric Fischer’s Geotagger’s World Atlas” series showed where photographic hotspots in various world cities were, using Flickr geotags. His Local and Tourists visualizations attempt to breakdown the photos into tourists and locals — blue is locals (people who have taken photos in the same city for more than a month), red is tourists, and yellow is indeterminate. People are using Flickr notes to explain popular photos ops.
GTWA was ordered by number of geotagged photos taken, and Chicago was on that list. The Locals and Tourists maps are ordered by number of photos and Chicago shoots to there.