NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Deviation plot
From: Scott Meyer
Date: 2002 Feb 5, 08:41 -0800
From: Scott Meyer
Date: 2002 Feb 5, 08:41 -0800
At 08:15 AM 2/5/02 +0000, Chuck Taylor wrote: >> on 2/4/02 12:47 PM, Chuck Taylor at ctaylor@PREMIER1.NET wrote: >> >> > The documentation for my Garmin Etrex Mariner GPS defines the following >data >> > items: >.. >> > Heading - Your moving direction. > >And John LeRoy replied: > >> Unfortunately the guy who wrote the manual is wrong. >> >> Actually your moving direction is track, sometime called course made good >> (CMG.) The GPS can't possibly know what your heading is ... > >Point well taken. That reinforces the point that it is important to be sure >that >you know what the GPS means when it says "Heading" (or anything else), because >what it means by "Heading" might not be what you think that word should mean. I don't have the Mariner, but I suspect that it may be similar to the other Garmins in that it has a fluxgate compass. Mine, the "Summit" uses the compass to display "Heading" if you're not moving fast enough to do it via GPS (or so the manual claims). Probably OK for walking around but hopeless for sailing. To make matters worse, they may use the same manual for several different models. -Scott Scott Meyer mailto:Scott.Meyer@oracle.com 650 355 0460 (h) "Endless Summer" F41 #17
