Chatty is a nifty piece of work where the researchers attempted to characterize an area’s sound. They did this by looking for geotagged photos which also have tags describing the contents. The content tags were used as a proxy for the types of sounds a person might hear at that location. For example, a picture tagged with #leaves might sound more like a natural setting than one tagged #construction.
From there, the authors associated sounds with emotions. By tying the photos to a street layer, they created a map of soundscapes with emotions one might feel when visiting that place. Neat.