Quakr is an on-line virtual world built from user contributed photographs and metadata. Developer Peter Arbuthnott shares the inspirations for this three-person project, and leads a whirlwind tour of its most compelling features.

Most people are amazed by the spatial experiences in Google Earth or MS Visual Earth which include 3D objects built from photographic data. Arbuthnott discusses how these bulky desktop applications run into limitations since their internal data cannot be easily refreshed, and that they lack the flexibility to harness the power of users. The Quakr team became inspired to ask whether a virtual world from user contributed photographic metadata could be built into the browser?

Quakr's viewer allows you to browse through a landscape of photos which have been tagged by users with latitude, longitude, altitude, a compass bearing, tilt, orientation and timestamp. The quality of the experience depends on the quality of that data which continues to improve as devices advance. To this end, Arbuthnott shows off a home brewed 7D-tiltometer which pulls together all the desired measurements.

Semantic consideration are critical in order to harmonize different terminology and geographic specs. Arbuthnott discusses some intriguing aspects of the APIs and rendering technologies that open up new possibilities for cool mashups such as a time slider for historic browsing. Probably the most crucial piece for the project's success is building a community of photographers with the energy to populate the 3D world with interesting photos.