Setting altimeters with no radio

"Peter Duniho" wrote in message ...
: "Jim Macklin" wrote in message
: ...
: they give altitude, accurate to within a few feet. just set
: the altimeter to read the same. then you know adjusted
: pressure. considering the legal requirements, it is
: perfectly adequate.
:
: First of all, no they don't give altitude accurate to within a few feet.
: Secondly, they give a completely different kind of altitude measurement than
: the altimeter provides. Even if the GPS were accurate to within feet for
: altitude, setting your altimeter to the GPS displayed altitude would not be
: the same as having the current, local altimeter setting.
:
: Pete
:
:

What about GPS precision approaches...where does the glideslope information come from?


WAAS?