Since Saturday, a new satellite has been transiting through space, the GeoEye-1. Its mission is to provide the highest resolution commercial images on the market to various companies and organizations, including Google, which will use the photographs to improve its Google Earth service.
GeoEye-1 will send images with a resolution reaching 0,45 meters in black and white and 1,65 meters in color. The satellite, which has cost around 350 million euros, will orbit around the Earth at more than 680 kilometers high at a speed of seven kilometers per second.
Media like this explain why Google has managed to photograph the entire planet in detail, almost 150 million square kilometers. In some cases, its attention to detail has raised alarm among those who monitor the right to privacy in public places.
Google has also tapped dozens of mapping agencies around the world. Just look at the credits that appear on the photo itself. Many carry the attribution "Image NASA", but as soon as we do a zoom meeting In detail, other authorships emerge: For example, "Cnes-Spot image" indicates that at least part of the image was obtained by the European Spot satellite. "Digital Globe" refers to an American company, which has its own satellites.
Other companies provide less obvious data. Europa Technologies supplies toponymy and digital border and coastline layouts. The Dutch Tele-Atlas specializes in roads and city maps. The Cartographic Institute of Catalonia recently provided Google with complete coverage of its territory based on high-resolution aerial images. The difference in formats with the adjacent images -Aragón, for example- means that with zoom meeting Catalonia looks different in color than the rest.
The newly launched GeoEye-1 is the most advanced civil photography satellite. So much so that it is beginning to approach the quality offered by military spy satellites. Its cameras have a resolution of 40 centimeters in black and white and just over one and a half meters in color. But, due to legal limitations, it will not offer the public images of less than half a meter.
The main customer of this satellite will be the Federal Geospatial Intelligence Agency, dependent on the Department of Defense. The second is Google, which has reserved the rights to exploit these images on the Internet. In fact, the rocket that launched GeoEye-1 had its logo painted on the fairing.
This satellite, like most of those that have preceded it, describes a sun-synchronous orbit: sigue to the Sun, so he always photographs the same places at the same time (10:30 in the morning) and under the same lighting angle. It flies at almost 700 kilometers high; Under normal circumstances it explores a strip 15 kilometers wide along its entire trajectory.
Spain, in a day and a half
The satellite's camera (actually a telescope) can process 700 megapixels per second. A day and a half would be enough for him to photograph all of Spain.
Some fear that these satellites constitute a threat to privacy. Not yet; With 50 centimeters of resolution it is impossible to identify a specific person. Although a vehicle and many details of the roof of any building can be located. Furthermore, maximum quality is only achieved on extraordinarily clear and cloudless days. These - and the night - are the worst enemy of an observation satellite.
In the absence of seeing the fruits of the new satellite, today, both on the Google and Microsoft world maps (Virtual Earth), cities in the United States and Australia are available with resolutions of 15 centimeters (aerial photography, not satellite). . In general, all of North America and Europe are seen at a resolution of 1 meter, although some cities such as Berlin reach 15 centimeters. The rest of the world, at 15 meters.
At the other extreme, cities like Manhattan or Hamburg are not only seen with high resolution, but are fully digitized, building by building and with photographic quality. The case of the small town of Westport, in Ireland, is famous. Rendered using a combination of long-range laser scanning and digital photography. Even the shop signs can be read.