[RE-wrenches] GPS units

[William Miller]

Does anyone have a foolproof tool to measure elevation?  I have researched 
GPS units recently.  They are notoriously inaccurate for elevation:

http://wiki.motionbased.com/mb/GPS_Unit_Elevation

Here are few more links with GPS fundamentals:

http://www.adventurenetwork.com/cgi-bin/adventurenetwork/GPS_101.html
http://www.gpsreview.net/electronic-compass/

I have a Suunto Observer watch with an altimeter.  I think I can get 
relatively accurate measurements of DIFFERENCE in elevation if I measure 
the two elevations in quick succession.  I will be trying it.



William