Hamilton Valley does have a compass course that all surveyors are required to
calibrate to.
bs
________________________________
From: Geary Schindel <gschin...@edwardsaquifer.org>
To: Gill Edigar <gi...@att.net>; "texascavers@texascavers.com"
<texascavers@texascavers.com>
Sent: Wed, December 30, 2009 11:33:55 AM
Subject: RE: [Texascavers] north pole moving
Some survey projects have done this. There were a set up calibration stations
at Mammoth Cave at the old Flint Ridge Field Station. I don’t know if there is
a set at the new Hamilton Valley site or not. However, if I remember correctly,
they were set up for magnetic north and not true north.
I also remember someone telling me what a giant pain it was to set them up
using a transit and finding folks who knew how to do it. I would assume it was
no trivial matter.
It would be interesting to plot the change in north over time with the same
compass using the same stations and see the shift occurring.
G
