The whole idea behind Google Earth is pretty amazing. The entire world is at your fingertips. It originally started as a project called Earth Viewer and was developed by a company called Keyhole. Google acquired Keyhole in 2004, and from there it became Google Earth.
I’m sure you’re aware by now that Google Earth is really a patchwork of images from a wide variety of sources. One way in particular that this is obvious is from the blurred locations. There are several locations that are blurred out– and each source blurs differently. One might white-out an area, another source will pixelize it.
Mark Aubin who is a software engineer working on the Google Earth project took some time to explain where all of the images come from. I always assumed that they used satellites and planes to get it, which they do, but it also comes from other sources like hot air balloons, model airplanes, and kites.
Now remember, it’s not like Google sends up the Google Hot Air Balloon or a Google kite to do this, third party agencies provide the imagery which Google then licenses from them.
Aubin explains how the traditional method for getting images come from “mounting a special gyroscopic, stabilized camera in the belly of an airplane and flying it at an elevation of between 15,000 feet and 30,000 feet, depending on the resolution of imagery you’re interested in. As the plane takes a predefined route over the desired area, it forms a series of parallel lines with about 40 percent overlap between lines and 60 percent overlap in the direction of flight. This overlap of images is what provides us with enough detail to remove distortions caused by the varying shape of the Earth’s surface.”
All of this information came from the Google Librarian Newsletter. With each newsletter they answer one or two frequently asked questions about Google Earth, so if you’re wondering something, ask. It’s pretty interesting to learn just how all of this comes together to form such an amazing application.