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What is the spatial resolution of imagery used in Google Earth? At various places on the web, I have been reading it varies from place to place - 60 cm, 2.5 m, 15 m and so on. I was wondering if there is any way/tool to find out what is the spatial resolution at a place of interest to me?

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4 Answers 4

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As for satellite imagery; most of the high resolution imagery in Google Earth Maps is the DigitalGLobe Quickbird which is roughly 65cm pan-sharpened. (65 cm panchromatic at nadir, 2.62 m multispectral at nadir) You can find out all the details here.

This is the first of the 3 DG satellites, the other ones are the Worldview-1 and 2. They capture imagery at about 50cm resolution, the 1st in only B&W the second which was launched fairly recently I believe in color and also 50cm but both deliver greater accuracy.

In Google Earth you can turn on the layer of DG coverage which gives you a visual reference of the various data captured as well as collect dated, etc. Google Earth only displays some of the collected imagery. There are many areas in the north where high resolution imagery exists but is not shown in GE or GM. You can use the DG layer in GE to search for imagery then look it up on the DG site to see what sort of could cover and season it was collected in. Often you can purchase much more up to date imagery then what is available in GE.

I think that the QuickBird satellite will be soon retired (2013?) so most of the satellite imagery in GE/GM might be coming from the Worldview-2 satellite. (Provided Google and DG will continue to collaborate)

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You can find basics information regarding resolution and accuracy on Google Earth wikipedia page.

Most land areas are covered in satellite imagery with a resolution of about 15 m per pixel. This base imagery is 30m multispectral Landsat which is pansharpened with the 15m [panchromatic] Landsat imagery. However, Google is actively replacing this base imagery with 2.5m SPOTImage imagery and several higher resolution datasets mentioned below. Some population centers are also covered by aircraft imagery (orthophotography) with several pixels per meter. Oceans are covered at a much lower resolution, as are a number of islands; notably, the Isles of Scilly off southwest United Kingdom were at a resolution of about 500 m or less, although this has since been addressed.

But I guess it's more complex since they mix several sources depending on the place you are.

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As you mention there is varying resolution of imagery

There is now no difference between Google Earth (& Pro) and Google Maps Satellite Mode (Though Google Earth gets the updates a few days faster than Google Maps) http://www.google.com/enterprise/earthmaps/pro_features.html

But you might be interested in Follow Your World

You can get updates from Google when your chosen area is updated.

enter image description here

http://followyourworld.appspot.com/ (Google login required)

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Go to the area of interest and zoom in as close as possible. Look at the center bottom of the window and you'll see the copyright notices. The lines reading "Image (C) YYYY XXXXX" are for the imagery (where YYYY is a year and XXXX is a company name).

You may be able to determine the resolution by searching Google. For example, zooming into 52d51m10.11s 7d49m28.72s shows an image copyright for Terrametrics. Searching Google for Terrametrics got me to their page describing the base map imagery that they provided to Google including the resolution (15m).

This probably won't work everywhere. But, it's one avenue to try.

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