On Friday we looked at a view of the earth at night created by NASA. Today we are looking at another map created by NASA called Blue Marble. We have looked at NASA’s Blue Marble images a number of times before. The early versions of Google Earth looked very patchy, just as it does today when you turn on ‘historical imagery’. Frank used the Blue Marble images to create a KML that could be used to make the Earth look better when viewed from high altitudes. Since then, Google has used similar techniques to achieve the same effect and built it into Google Earth.
If you want to see the Blue Marble images today, the easiest way is to download this KML file
, which comes from this map posted by NASA in the Google Maps Gallery. It includes twelve layers, one for each month of the year. There are downsides to using the version from the Google Maps Gallery. You cannot save the map to your ‘My Places’ and the KML cannot be used as part of a larger KML so it cannot easily be animated as Frank has done previously. It would have been nice to do a new animation using the Maps Gallery version, as it is higher resolution than the ones Frank used, and is regionated, which improves performance. High resolution images of the maps can be obtained from NASA’s website, but they are quite large.
Blue Marble – January 2004. The Blue Marble images must be composites selected from days with minimal snow cover.
Last week we showed you some Landsat imagery and noted how Google Earth is much greener than the Earth is in reality. The Blue Marble images do show the seasons and the snowline moves with the months, but comparing it to the Landsat imagery suggests that even the Blue Marble images have the snow cover reduced to a minimum.
About Timothy Whitehead
Timothy has been using Google Earth since 2004 when it was still called Keyhole before it was renamed Google Earth in 2005 and has been a huge fan ever since. He is a programmer working for Red Wing Aerobatx and lives in Cape Town, South Africa.