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I'm involved with the Highland County Cave Survey (VA).  The project is
intended to discover and detail caves in the area.  At this time we are
walking the county farm by farm, a difficult and time-consuming endeavor
considering our small numbers.
 
We would like to know whether infra-red imagery of the area would expedite our
project by revealing near-surface heat sources.  Ideally, the images should hav
e been taken in winter in order to maximize the temperature differentials.
 
Thanks
   Frank