Building the World, one photo at a time

Is it possible to build a virtual world from user-contributed photographic metadata?

The Giants’ Approach: control everything Google Earth and Microsoft’s Virtual Earth have 3D elements, but they have both chosen to control the data that creates those elements. Microsoft’s photo-realistic cities are ‘built’ from especially commissioned photos.

An Alternative: we the people But the data is already out there. Amateur photographers have readily adopted the concept of location metadata; there are currently 0.5 million geotagged photographs on Flickr. Meanwhile, digital cameras embed Exif metadata (some already include GPS data), and geo-standards including KML and GML are in widespread use.

The view from 30,000 feet Where are the overlaps between what the standards advocate, what cameras can provide, and what people actually do in practice?

Data (1): wish list Is the data sufficient? What data does a 3D rendering engine ideally need to position photos in 3D space? Are the geo-standards sufficient to describe that data set? If not, how might they be extended? Could users realistically contribute that data set? What tools would help them?

Data (2): making do Finally, to what extent can an open-world-minded application make sense of the sparse, ambiguous data which is avaliable right now?

Our application This paper describes the experience of developing a 3D virtual world, based on publically available images and existing geo-metadata, including Flickr. We make recommendations for extending geo-metadata standards to facilitate such applications, and we document our D.I.Y. efforts at constructing a geo-camera of the future, capable of capturing the metadata we advocate.

Our application sits in the heart of the ubiqitous web, at the intersection between increasingly sophisticated gadgets, metadata standards, and the surprising extent to which users are interested in both.