s.m at group-s.sk
Thu Dec 20 16:03:24 CET 2007
According to Wikipedia (http://en.wikipedia.org/wiki/Magnetic_declination)
Declination converts between true and magnetic bearings: True Bearing equals
Magnetic Bearing plus Magnetic Declination. (See
In therion - declination is implemented this way (to avoid confusion), while in
(true bearing) = ((bearing)-(declination zero err))
Thanks for pointing out, we will mention this difference in thbook.
Quoting Wolfgang Zillig <wolfgang.zillig at web.de>:
> I've just changed one input file from survex format to therion format to
> get the LRUD data into the model. The declination is corrected manually
> by "declination xx degree" within the centreline. I've noticed that I
> had to change the prefix from "-" (minus) to "+" to get the same result
> as with survex. In survex it is done by "*calibrate declination xx".
> It would be nice to add a comment in the Therion book that declination
> correction is opposite from Survex.
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> Therion at speleo.sk
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