Wednesday, April 29, 2009

The Most Photographed Places in the World

A team of Cornell researchers has developed a method for mapping out the locations of about 35 million images from Flickr. The resultant visualizations, as described in their paper (pdf), look like this image, which shows the locations where Flickr photos were taken, and includes representative images of the most photographed landmarks in the 20 most photographed cities in Europe.



The goal of their work is to "investigate the interplay between structure and content — using text tags and image features for content analysis and geospatial information for structural analysis." In other words, all photographs are of places; it therefore makes sense to organize them spatially, i.e., with maps. Furthermore, this information can be combined with the subjects of photographs to, as the researchers put it, create
a fascinating picture of what the world is paying attention to. In the case of global photo collections, it means that we can discover, through collective behavior, what people consider to be the most significant landmarks both in the world and within specific cities; which cities are most photographed; which cities have the highest and lowest proportions of attention drawing landmarks; which views of these landmarks are the most characteristic; and how people move through cities and regions as they visit different locations within them. These resulting views of the data add to an emerging theme in which planetary-scale datasets provide insight into different kinds of human activity — in this case those based on images; on locales, landmarks, and focal points scattered throughout the world; and on the ways in which people are drawn to them.
The researchers analyze photos taken at the levels of both metropolitan areas and individual landmarks. They can determine, for instance, that the seven most photographed landmarks in the world are

1. The Eiffel Tower
2. Trafalgar Square
3. Tate Modern Art Museum
4. Big Ben
5. Notre Dame Cathedral
6. The London Eye
7. The Empire State Building

They can also rank landmarks within cities; the three most photographed places in Boston, for instance, are Fenway Park, Trinity Church, and Faneuil Hall.

The ten most photographed cities, meanwhile, are

1. New York
2. London
3. San Francisco
4. Paris
5. Los Angeles
6. Chicago
7. Washington
8. Seattle
9. Rome
10. Amsterdam

Another interesting product of their work is that, using time stamps on photos, they're able to approximate the routes traveled by Flickr photographers.
Geotagged and timestamped photos on Flickr create something like the output of a rudimentary GPS tracking device: every time a photo is taken, we have an observation of where a particular person is at a particular moment of time. By aggregating this data together over many people, we can reconstruct the typical pathways that people take as they move around a geospatial region. For example, Figure 1 shows such diagrams for Manhattan and the San Francisco Bay area. To produce these figures, we plotted the geolocated coordinates of sequences of images taken by the same user, sorted by time, for which consecutive photos were no more than 30 minutes apart. We also discarded outliers caused by inaccurate timestamps or geolocations. In the figure we have superimposed the resulting diagrams on city maps for ease of visualization.
The top image shows pathways through Manhattan; the densest movement appears to be through Midtown and the Times Square area, with a secondary area of popularity in Lower Manhattan and across the Brooklyn Bridge. The bottom image shows pathways in the San Francisco Bay area; downtown appears to be popular, as well as the trendy neighborhoods of Nob Hill, Russian Hill, North Beach, and the touristy Fisherman's Wharf. Golden Gate Bridge and what looks to be the University of California at Berkeley are secondary nodes of interest.

This is all very reminiscent of what the folks at Columbia were trying to do in describing the geography of buzz; it depends on the same principle that we can learn something about what places are important by analyzing what places people are paying attention to, and we can do that by looking at what places people are taking pictures of. It's a clever idea, and an example, I think, of how the digitization of information is allowing us to have an exceptionally more fine-grained understanding of not just the world itself, but also of how we look at the world. But it also recalls something from Don DeLillo's novel White Noisein which a bridge somewhere in the Midwest is famous for being the most photographed bridge in the world. In other words, it's famous just because it's famous; and the experience of perceiving the object - famous for being perceived - becomes a weirdly important moment for the perceiver in that it authenticates the perceiver's sense of belonging in society and in history (what Umberto Eco might call a hyperreal moment). And I think it's true that people find it important, for whatever reason, to document their perception of highly-perceived objects like the Eiffel Tower - your photo of the Eiffel Tower is the "proof" that you've been to Paris; it's a token of a certain sort of experience, not because the Eiffel Tower is itself important, or particularly interesting to you, but because it is an iconic representation which many people can relate to precisely because it is a famous image with which people are familiar; it is, in short, famous for being famous. (Look at the images of landmarks on postcards at any sidewalk vendor in the world for other examples of images which have this same function of authenticating one's experience of a place.) But if this is the case, then I don't think the authors of this paper are justified in claiming that what they've documented is "what people are paying attention to," because taking a photograph of something is not necessarily a significant act of "paying attention to" something. Rather, it is often the more trivial act of doing something like documenting your perception of the most often perceived bridge in the world; it is a documentation of your having seen something which is famous for being seen. So at the end of the day, these researchers' exercise has a certain circular quality: it is documenting what places people are paying attention to based on what places people believe are being paid attention to. It's sort of interesting to have such documentation; but it doesn't amount to a documentation of what places are "most important," or even of what places people are paying most attention to. If people are genuinely focused on some object, after all, in most cases they probably wouldn't even think to photograph it.

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