In message .com
"fat_boy" wrote:

How? If a GPS devices prime role is to give the lat and long, it will
give you your position in terms of a flat grid on the earths surface.

For it to calculate speed, it measures the change in distance over time
relative to that flat grid.

So, unless the GPS unit ALSO measures altitude, and can add a vertical
component to the calculation, it can not work for skiing.


You're clearly out of touch with modern GPS devices. I have a Geko301
which includes data for both barometric and GPS altimeter and can do
auto correction of one by the other over time. The software in the
device also includes algorithms to calculate things such as glide ratio,
average rate of descent and also average rate of ascent, primarily
designed for aerial pursuits such as parachuting and paragliding but it
would also allow the read out of a ski descent.

I've collected active data on the Geko 301 whilst skiing and it is easy
to analyse data later on a PC for all kinds of parameters using software
such as GPS Utility.

Mike http://www.path.cam.ac.uk/~mrc7/cccc/hauteroute/
--
o/ \\ // |\ ,_ o Mike Clark
\__,\\ // __o | \ / /\, "A mountain climbing, cycling, skiing,
" || _`\,_ |__\ \ | immunology lecturer, antibody engineer and
` || (_)/ (_) | \corn computer user"