 Check out the bookstore at IRBS.com |
|
|
|
|||||
|
||||||
Subject: Re: Variation of compass
From: Herbert Prinz (hprinz@XXX.XXX)
Date: Wed Oct 02 2002 - 20:13:08 EDT
This is an inherent limitation of the underlying prediction model. It's a
compromise between better reliability for a shorter time or lesser accuracy for
a longer time. DMA chart 42, or whatever else one might use in its place,
suffers the same limitations. It's all based on the same methods and data.
Herbert Prinz
Robert Eno wrote:
> [...] GPS receivers have a built-in program that provides the magnetic
> variation for
> any place on the planet. The drawback to this feature is that is only valid
> for a certain epoch which I think is no more than 5 - 10 years.
|