[UFO Chicago] Google Maps vs Terraserver

[Jordan Bettis]

Neil R. Ormos said:
> On Fri, 14 Oct 2005, Jordan Bettis wrote:
>
>> Google appears to get most of its aerial survey data from
>> <http://digitalglobe.com>. According to this:
>> <http://en.wikipedia.org/wiki/Google_earth> the data is "usually less
>> than
>> three years old." This confirms that terraserver gets its data from
>> USGS:
>> <http://en.wikipedia.org/wiki/TerraServer-USA>. Interestingly it used to
>> have Russian data as well.
>
> I don't think that anyone was saying that the
> satellite image data distributed by Google and the
> map data distributed by Terraserver arrive at each
> distributor via identical routes or are perfectly
> coextensive.
>
> What I did say was that the satellite image data
> distributed by Google is derived from the same
> USGS imagery that Terraserver delivers via the
> "Urban Areas" tab, at least for the Chicago area,
> and that the Google-provided imagery seems to have
> been stripped of some color depth.  TerraServer
> itself credits USGS as the source of its imagery.

Everything on digitalglobe's website suggests that all
the data they sell is produced by them. It is possible
though that the Chicago data in question is USGS data.
Google appearently uses many sources for their satellite
and aerial photo data, but DG appears to be their main
source.

-- 
Jordan Bettis -- Chicago Il.
  <http://neighborhoods.chicago.il.us>
    Photographs of Life in the Neighborhoods of Chicago