Naked Science Forum
Non Life Sciences => Technology => Topic started by: neilep on 31/03/2009 18:24:42
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Hi All,
As ewe know Google Earth can have ewe zoom in like this and get some quite nice detail...Actually, The photography in Virtual Earth is really good too...
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What kind of camera is used to take these photos ?..are they all satellite based or are some on airomobiles ? How high up are these cameras ?
Thanks
Neil
xxxxx
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For that level of zoom, I believe most of the images are from aircraft, at a guess, flying between 5000-10000ft (based on some images that have captured aircraft flying in VFR conditions and out of the airways, which I think puts them below 3000ft).
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Some of the images are from aircraft and some from satellite. That particular image, I believe, could be from either though I think satellite. Images from aircraft can be much better and I guess, therefore, would be the higher resolution ones. The satellite ones can be better too, but are not available for commercial applications. A clue is that many images are taken in early morning (the sun is low) when there is often clearer skies - you sometimes also have problems with cloud which you can observe to be a long way down.
A further clue is that very many pics are at oblique angles and corrected to look like a map-view; you can tell this because you can see the sides of tall buildings and, if you tilt and move the view around, you can work out from where the picture was taken. Pics from satellites have to make good use of the time available and the orbit positions are limited. My guess is that aircraft pics would be mostly directly downwards and are taken from aircraft used for mapping purposes - I may be wrong though because aircraft time isn't cheap either. I think Google attribute where they buy there pics from though don't say which are which.
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its ts just a satellite camera
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Here's how it's done http://pict-earth.blogspot.com/ (http://pict-earth.blogspot.com/)