Wednesday, 3 June 2009

Movement Mapping Using Flickr


As a by-product of a research project called “Mapping the World’s Photos” a nice movement map was generated. The work by Davis Crandall, Lars Backstrom, Daniel Huttenlocher and Jon Kleinberg from the Department of Computer Science, Cornell University is looking at organizing a large collection of geotagged photos. Large in this context means something around 35 million images, collected from Flickr via the public API. The main hypothesis of the project is “that geospatial information provides an important source of structure that can be directly integrated with visual and textual-tag content for organizing global-scale photo collections”. They where using image recognition software to locate the photos together with the interpretation of the photo tags.
In this context the computation bit behind this is not the focus of the interest, although it sounds very impressive. If you are interested in this bit, have a look at their paper directly, which is published online here.
The bit I am interested for this post is the bit where they plot the geospatial information. As they describe it in their paper it was more of a by-product that came with the project, but never the less it generated interesting visuals.
By using the time stamp and the geolocation the movement of the photographer can be traced. Similar to a rough GPS track the different locations a photo is taken can be mapped as a sequence in space and time. Crandall et all where plotting this information and the result was a series of urban tourist’s movement maps. In the paper they published two of them on of Manhattan, NY and the other one of the San Francisco Bay area.

MappingTheWorldsPhotographer01
Image courtesy of David Crandall / New York - 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.

A great way to collect data by mining the existing and continuously growing, as they call it “global photo library” by using the public API and the published image information. It is a project very similar to the recently posted project “Just landed”, where the Twitter API was used together with a tweet analysis regarding phrases containing “just landed” to map global movement.
The selection of the image generators, the photographers and sharers is again, just as it was with twitter a critical point. Who does this represent, who is this group and what can we learn from this groups data?

An other city mapped by the photos taken is London.
London generated from FLickr photo locations
Image courtesy of David Crandall / London as seen through the camera clicks shared on Flickr with geolocation.

Quoted paper: David Crandall, Lars Backstrom, Daniel Huttenlocher and Jon Kleinberg, 2009. Mapping the World’s Photos.

Found through 7.5th Floor by Fabien Girardin - As he points out in his blog post there are a number of related projects including Currid and Williams’ work on Mapping the Cultural Buzz.

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