How Google Earth works

Posted on February 19, 2006
Filed Under I'm lovin it |

Starting with an icosahedron (a), the triangular
tiles are split into 4 smaller tiles (b), and re-mapped into a shape
approximating a sphere (c). The process is then repeated (d,e,f).
The globe-imaging software Google Earth has become a cult web product since its release last June. Using the web-based tool, users can fly around the globe and zoom in on both natural features and whole worlds of information added by other users (see ‘The web-wide world’).

But how is it possible for you to zoom in from outer space to a point somewhere above the rooftop of your house without bringing your desktop computer to a grinding halt?

The main obstacle to a convincing three-diménsional skydive is data transfer. If one were to download over the Internet a one-metre resolution image of the entire world it would take 69 years with a 10-megabit-per-second Internet connection, and 12,400 years with a standard 56K modem.
via nature.com read on if you like

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