"Matt Barrow" wrote in message =
...
=20
"John R. Copeland" wrote in message
...
=20
In the Rockies, there are ground stations at widely varying =
elevations.
I've guessed that ATC might not use settings from airports in deep =
valleys
for enroute settings, wherever more representative values are =
available.
=20
How would a station be more representative if it was/wasn't in a =
valley or
on a hill top?
=20


In the case of non-standard lapse rates, the lower the airport,
the more the altimeter differs from true height across mountain peaks.