How current are the images that we see when we use satellite image web sites?

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p.mcneel

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I would like to know how current the images are. Are they a month old ,a year old, two or what.? How often do they update them would be kind of interesting to know also.
 
One good way to find out is to visit google earth and check out how up to date the images there are versus natural disasters such as the bush fires in Australia recently, or construction progress in your own locale.

Like google earth was still showing a perfectly intact New Orleans for weeks after the flooding disaster there.
 
Google Map's images of New Orleans are three years old, unless they have updated them within the last two or three weeks. Microsoft Virtual Earth's images of the New Orleans area are more recent. Some image atlas I found had New Orleans images from September 18, 2007 supposedly. On Google Earth you MIGHT be able to tell when an image was taken, but I found it very confusing and gave up. I've been working with satellite images since the spring semester of 1993. Remote sensing is one of my obsessions. I could tell, some times, where images from different times had been mosaic-ed together because I could see the seam and the change in colors where images had been stitched (mosaic-ed) together. How often they are updated is entirely up to company providing the service, Google, Microsoft Virtual Earth, DigitalGlobe, etc.
 
It depends on what's available and how much it costs. The area I live in (rural) uses a satellite image that is at least 20 years old, judging by the highway construction visible in it. The area I used to live in (urban) has had updated images several times over the past few years. The county I live in has online aerial photographs which are far more detailed and up-to-date than Google Earth, etc.
 
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