[pct-l] GPS Altimeters

[elee at microsoft.com (Eric Lee (GAMES))]

Vic wrote:
>
I am still confused on GPS units, please help! The more expensive ones
have a barometric altimeter. Acording to the Garmin website, it takes
two sats to get a location, three to get altitude. I take this to mean
that any GPS can give you the altitude reading, it this correct? If so,
what is the advantage of having a barometric altimeter in a GPS? I was
with a friend a few weeks ago, he was using a Garmin Summit. When he
checked the altitude, it asked if he wanted to calibrate by satelite.
When he did, it showed an altitude over 500 feet greater (we were at
16,000', in a car, having lunch!).
>

Well, I would hope that the people at Garmin knows what they're talking
about, but all the information I've ever read says that three satellites
are required to get the location and four are required for altitude.

Eric