Google is mining photos from a satellite launched in 2013 to create a better, cloud-free image of Earth from above.
The newest mosaic is an updated version of one produced in 2013. The new version was pieced together mostly using data from the Landsat 8 satellite, launched by NASA, which snaps “twice as many images as Landsat 7 does every day,” according to Google.
“This new rendition of Earth uses the most recent data available — mostly from Landsat 8 — making it our freshest global mosaic to date,” Chris Herwig, program manager for Google Earth Engine wrote in a blog post.
Much of Earth is usually covered by clouds, but Google Maps combed through photo after photo to piece together the “clearest pixels” from more than 700 trillion pixels. The result is an unobstructed view of the Earth’s surface with more details visible than before.
New York before
New York after
“Our previous mosaic used imagery from Landsat 7 only, which at the time was the best imagery of its kind,” Herwig said. “Unfortunately, Landsat 7 images captured after 2003 were affected by a hardware failure, resulting in large diagonal gaps of missing data.”
Scientists can glean a lot from this kind of data, getting a sense of deforestation and urban development in different parts of the world.
Much of this data is freely available from the Landsat program, which has been imaging Earth’s surface with various satellites since 1972.
Landsat 8 is the newest satellite in the fleet.
You can explore the cloud-free imagery yourself either using Google Earth or through the satellite layer on Google Maps.
Source : http://mashable.com/