Re: Deviation plot
Subject: Re: Deviation plot
From: Scott Meyer (smeyer@XXX.XXX)
Date: Tue Feb 05 2002 - 11:41:43 EST
At 08:15 AM 2/5/02 +0000, Chuck Taylor wrote:
>> on 2/4/02 12:47 PM, Chuck Taylor at ctaylor@XXX.XXX 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@XXX.XXX 650 355 0460 (h)
"Endless Summer" F41 #17
