Penmachine

Since 1972, the Landsat satellites have been photographing the surface of the Earth from space. However, the amount of data involved meant that only recently could researchers start assembling the millions of images into an actual map, where they could all be viewed as a mosaic.

NASA has posted an article explaining the process. The map covers only land areas (including islands), but it is not static—it includes data from different years so you can see changes in land use and climate.

Here's the neat thing. Back in the 1980s, while the information was there, putting even a single year's images into a map would have cost you at least $36 million (USD). Now you can get the whole thing online for free. Take a look. If you poke around, there's a lot more info than in Google Earth.

Labels: astronomy, geekery, photography, science, space