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                T               V               M               D
C

                316d            11dE            305d


When going from left to right I have been subtracting Var East and adding
Var West.
All of my books tell me that this is the right way to do it.
Does anyone have documentation that this is wrong?

Bill Allan



-----Original Message-----
From: Andrew Denman [mailto:megnden@OZEMAIL.COM.AU]
Sent: Monday, February 11, 2002 2:04 PM
To: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM
Subject: Re: Newbie - Variation Question


Pierre,

Thanks for the reply but I am still a little confused.  Even if the French
way is to add the negative easterly variation, shouldn't the resultant
magnetic heading be the same as the non French way?

In my case, my compass was reading 305 magnetic, variation is 11 degrees
East at my location.  Before adjustment for local magnetic variation, the
GPS was giving me a course relative to true north of 316 degrees true.  When
I put in the local variation, rather than the GPS displaying a magnetic
course of 305, it added the 11 degrees easterly variation to give a magnetic
course of 327 degrees magnetic.  It would appear that the unit  treats the
Easterly variation as positive.  When I input the variation as 11 degrees
West, the unit subtracted the variation to give me a magnetic course of 305
degrees, same as the compass.

My other fixed GPS (Garmin) subtracts the Easterly variation to agree with
the compass.

Any other clarification would be appreciated.

Regards,

Andrew Denman

   

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