Michael Mcneil wrote:

"Karl Cooper" wrote in message


English cities showing up well on the current (20:38 UTC) image:

http://en.allmetsat.com/images/noaa_dlr_uk.php

I take that the dark regions are the centres?

At its simplest it is dark where there are buildings and light where
there is vegetation. Nothing too surprising about that - green
chlorophyll reflects near IR radiation...

You can see the difference between dense cities even in the visible.
Concrete and rooves show up clearly as a different colour to grass etc.

Regards,
Martin Brown