The updating is done piecemeal by the firms who supply the photos.
Different panels of a given mosaic provide clues, both in terms of things
that existed only up to a certain date, or only after a certain date, and by
things like the angles of shadows, and the angle of cameras in relation to
their subject. There are several easily spotted instances of buildings
'leaning' toward or away from each other. All of these indicators are visual
confirmations that a variety of cameras working at a variety of times over a
period of years are producing a multitude of images that are stitched
together to give a reasonably coherent image.
Not sure who to recommend for further confirmation. But browsing some of the
mapping and/or Google blogs might help.
hth
David
__________________
David Papadopoulos
65D Oxford Road
Moseley
Birmingham B13 9ES
0121 242 1845
-----Original Message-----
From: A forum for critical and radical geographers
[mailto:[log in to unmask]] On Behalf Of Dr Hillary Shaw
Sent: 07 May 2006 20:47
To: [log in to unmask]
Subject: Google Earth images
Does anyone know if the Google earth images are updated, and if so how
often. I have examined various parts of the UK with a view to dating these
images and my guess is 2004 or 2005 (probably not all images are the same
year, as cloud cover has been minimised - but maybe 0.1% cloud cover still
there on some images).
If they're updated, be interesting to know how often, as one could follow
changes where these are occuring relatively rapidly, eg Aral Sea coastline.
Also could then follow urban change, the images of larger cities are v
impresssive, individual bldgs, gardens show well.
Hillary Shaw, Geography, Southampton
|