Google Earth 6.2 Uses Simple Algorithms To Look Good
Written by Harry Fairhead
Friday, 27 January 2012
What a difference an algorithm makes. Add a simple photo processing technique to Google Earth and the result really is a beautiful world.
If you are a fan of Google Earth then you will be very pleased to have the latest version 6.2 because it does away with our patchwork planet.
Users of any satellite imaging system are very accustomed to seeing the differences in the tiles that make up the view as a sort of chequerboard effect. This is due to the fact that the tiles correspond to a mosaic of satellite images taken on different days in different lighting conditions. The result is that the tone of adjacent tiles can be very different. And yet how easy it would be to simply apply a tonal correction to make adjacent tiles occupy the same area of color space. This is exactly that Google Earth 6.2 does:
Today, we’re introducing a new way of rendering imagery that smooths out this quilt of images. The end result is a beautiful new Earth-viewing experience that preserves the unique textures of the world’s most defining geographic landscapes—without the quilt effect. This change is being made on both mobile and desktop versions of Google Earth. While this change will appear on all versions of Google Earth, the 6.2 release provides the best viewing experience for this new data.
If you try it out then you will find that the result really is a "seamless globe". This one fairly simple change really does increase the apparent quility of the presentation. For example take a look at the Grand Canyon before:
The improvement is obvious but there is still scope for improving the algorithm in use. It seems that the matching is being done on the boundaries of tiles and this sometimes goes wrong. For example, if there is some cloud cover that obscures a tile but isn't in the adjacent one, then the color recalibration fails. For example:
As well as the tonal matching algorithm the new version includes features in support of Google+. You can now share a screen dump or current view via Google+. I can imagine this would be occasionally useful but not something most users want to do on a regular basis. The search facility has also been redesigned with the addition of autocomplete.
Google Earth 6.2 is available for download now and it's free to use.
Twitter is creating an index of every public tweet ever made, to make it possible to search without restrictions on the age of the tweet. This is being achieved using Apache Mesos, an open source [ ... ]