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Personal connections may be what a lot of people want, but going by the numbers, Google Earth is far more popular than any other type of virtual world, including the big role-playing worlds like Lineage II (which has 14 million subscribers) and World of Warcraft (more than 8 million). By the spring of 2007, less than two years after it was launched, Google Earth had already been downloaded more than 250 million times.

Google Earth and its lesser-known imitator, Microsoft Virtual Earth, owe their existence to a convergence in the early 2000s of several trends, including a drop in the price of satellite and aerial imagery, the more widespread availability of topographical and other geographical information collected by national governments around the world, the standardization of 3-D modeling technologies originally developed for video games, and the spread of consumer PCs with graphics cards capable of 3-D hardware acceleration. But the programs’ philosophical roots go back much further than that. John Hanke, who developed the original software behind Google Earth at a small company called Keyhole (which Google acquired in 2004), says that Snow Crash’s description of a 3-D program called Earth–“a globe about the size of a grapefruit, a perfectly detailed rendition of Planet Earth”–was part of his inspiration.

An equally detailed vision of a virtual earth was laid out in another book from the same era, David Gelernter’s Mirror Worlds: Or the Day Software Puts the Universe in a Shoebox … How It Will Happen and What It Will Mean. “The software model of your city, once it’s set up, will be available (like a public park) to however many people are interested,” Gelernter predicted. “It will sustain a million different views. … Each visitor will zoom in and pan around and roam through the model as he chooses.” Institutions such as universities and city governments would nourish the mirror world with a constant flow of data. The latest information on traffic jams, stock prices, or water quality would appear exactly where expected–overlaid on virtual roads and stock exchanges and water mains. But just as important, mirror worlds would function as social spaces, where people seeking similar information would frequently cross paths and share ideas. They would be “beer halls and grand piazzas, natural gathering places for information hunters and insight searchers.”

On page 203 of Mirror Worlds is a striking architectural drawing showing a bird’s-eye view of a fictional city distinguished by elegant skyscrapers, broad avenues, and abundant parkland. Superimposed on the view are several blank white boxes where, in Gelernter’s hypothetical mirror world, information about the streets and buildings would be displayed. The caption describes the drawing as “an abstract sketch, merely the general idea” of what a ­mirror-­world interface might look like.

If the sketch looks familiar today, it’s because thousands of views like it can be found using Google Earth or Microsoft Virtual Earth, complete with 3-D buildings and white pop-up info boxes. There are superficial differences: the Google and Microsoft cityscapes, for example, are photo­realistic, at least in the limited areas where buildings are covered with “skins” based on photographs of the real structures (like the virtual Amsterdam in Second Life). But ­Gelernter anticipated so many features of today’s ­virtual-globe software that these programs could readily serve today as the windows on a mirror world as he imagined it. In fact, Google Earth users can access a growing library of public and personal data, from national borders to Starbucks locations, jogging routes, and vacation photos–in effect, any kind of information that’s been “geocoded.”

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Credit: Technology Review

Tagged: Communications

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