"Geo-caching is fun, but the most intriguing new applications of GPS may end up transforming everyone's sense of physical space. What if you think of GPS as a kind of 3-D version of the Internet, a hypertext Web spun out in real-world geography?
GPS is based on the fundamental geometric principle of trilateration: If you know your distance from three distinct points, then you know your exact position on a map. (If you're interested in altitude as well, you need four points.) GPS receivers coordinate with a system of 24 satellites maintained by the Department of Defense. Because these satellites follow predictable orbits, their exact location at any given time is easy to determine. A GPS receiver in your car or on your personal digital assistant (PDA) receives radio signals from satellites overhead and gauges its distance from each satellite by calculating how long it takes the signals to arrive. Before 2000, the military deliberately scrambled GPS signals for consumer use to limit the precision of location readings. However, today the accuracy range of ordinary receivers is typically 30 feet. (Some high-end models, using several frequencies, can generate accurate location readings to within a foot.)...
The great breakthrough on the GPS horizon lies in thinking of those geographic coordinates as a real-world URL. In other words, think of those digits not simply as a description of a point in space but as a place to store information. Today you can create a Web address and publish pages and pages of anything you want there. But soon you'll be able to take a GPS location—say, 40°43.833' N, 073°59.814' W, the coordinates for Washington Square Park in New York—and publish material there as well. Anyone walking through the park would then be able to browse through the data you've uploaded. Some of this information might be targeted at a general audience and include recommendations for nearby restaurants, or a public bulletin board for discussing improvements to the park itself. But the messages stored might also be more personal, such as diary entries stored at the very place where the events described in the diary occurred, a kind of first-person geo-cache. There might even be bits of text targeted at a specific person, like an e-mail message floating in space, waiting for its recipient to come into range and receive it.
IBM researcher J. C. Spohrer, who helped concoct an early prototype for a GPS-based hypertext called WorldBoard, describes this kind of system as a 'planetary chalkboard.' I prefer to think of it as a kind of graffiti that makes an environment more habitable and socially connected....
The planetary chalkboard will become interesting only when ordinary people can pick up a piece of chalk and write something.
'Instead of having just tourist information, the system would be open,' says Swedish researcher Fredrik Espinoza, cocreator of an experimental tool called GeoNotes. "There would be much more social activity." Espinoza's vision includes a filtering system for retrieving GeoNotes that have been posted by friends or other trusted sources, like the buddy list of Instant Messaging. Imagine, for instance, that you stumble across a beautiful side street in a historic district, the sort of urban discovery you might tell your friends about the next time you meet them for coffee. With GPS-based hypertext, you could leave a virtual note hanging near the street, addressed to your 30 closest friends. The next time they happened to stumble through the area, the text would pop up on their PDA screens: 'Hey, come check this out...'
William Gibson, the sci-fi writer who coined the term cyberspace, once wrote: 'The street finds its own uses for things, uses the manufacturers never imagined.' His words are inevitably rolled out when describing some unlikely new grassroots application of an existing tool, like geo-caching. But software such as GeoNotes or WorldBoard suggests a further twist: The street finds new uses for the street itself. Simply strolling down the sidewalk can become a hypertextual exploration, a journey into a new information space layered over the real one. Suddenly the surrounding air is full of information—some of it created for you by your closest friends, some of it created by total strangers. The streets are alive with data." [Discover, via stevenberlinjohnson.com]
Thursday, January 16, 2003
