[X] My Assistant

[Bjorn Jonsson]

For some reason it didn't come to my attention until recently (less than a year ago) that the entire Landsat imagery plus a lot of data from other Earth orbiting spacecraft is freely available for download at http://earthexplorer.usgs.gov/ . Maybe this is because for a long time it was more difficult to find good and freely available global maps (or get data to make maps) of the Earth than it was for other planets/satellites - I somehow was under the impression that the vast majority of Earth imagery was commercial.

The Earth is visually a really spectacular planet (in my opinion possibly even the most photogenic body in the entire solar system) so it's possible to get spectacular results by downloading some of this data. The data can be selected by spacecraft, instrument, location, months/years, cloud cover percentage etc.

Data is available from several Landsat satellites but the best data is from Landsat 7; Landsat 5 is also good. This is multispectral data with a resolution of 30 meters/pixel. Here is an experimental and spectacular 12 frame mosaic showing southern Greenland (10% the original size):



The full size version (19000 pixels square) plus additional information can be seen in this blog entry at the Planetary Society website. This image shows a spectacular and complex 'maze' of long and narrow fjords and islands, narrow valleys flanked by steep mountains, glaciers and glacial rivers, countless lakes and ponds and in general a landscape that has been shaped by advancing and retreating glaciers, depending on climate. One important thing to note is that overall this data turned out to be easier to process than is typical for data from other planets.

[monty python]

Sean, thank you so much. ART!