As the internet becomes intertwined with the real world, the resulting “geoweb” has many uses
Sep 6th 2007
“EARTH materialises, rotating majestically in front of his face. Hiro reaches out and grabs it. He twists it around so he’s looking at Oregon. Tells it to get rid of the clouds, and it does, giving him a crystalline view of the mountains and the seashore.”
That vision from Neal Stephenson’s “Snow Crash”, a science-fiction novel published in 1992, aptly describes Google Earth, a computer program that lets users fly over a detailed photographic map of the world. Other information, such as roads, borders and the locations of coffee shops can be draped on to the view, which can be panned, rotated, tilted and zoomed with almost seamless continuity. First-time users often report an exhilarating revelatory pang as they realise what the software can do. As the globe spins and switches from one viewpoint to another, it can even induce vertigo.
Google’s virtual globe incorporates elevation data that describe surface features such as mountains and valleys. Other data is then overlaid on it, notably a patchwork of satellite imagery and aerial photography licensed from several public and private providers. The entire planet is covered, with around one-third of all land depicted in such detail that individual trees and cars, and the homes of 3 billion people, can be seen. All this has long been imaginable but has become possible only recently, thanks to high-resolution commercial satellite imaging, broadband links and cheap, powerful computers.
