Thanks everyone for your comments. My project involves plotting every state
grant and deed for a militia district for 50 years, so maybe by paying
attention to any changes in legal descriptions I can determine how much to
rotate plats (if at all).
I just looked at the sites I found, and the historic declination site is
DeedMapper's site! http://users.rcn.com/deeds/decl.htm
The 20th Century calculator is from NOAA and is at
From: William Doyle [mailto:email@example.com]
Sent: Thursday, October 07, 2004 3:06 PM
Subject: RE: [DMU] Determining and Using Magnetic Declination
I would be very interested in the URL of the web site you found with
magnetic variation in each decade of early state's modern capitols.
I looked for but did not find such information for North Carolina in the
period 1760 - 1810. I was able to get a fix on magnetic north in 1790s from
the directional description of one property line that was common to the
Orange County Line. If you have a metes and bounds description for a
property that has a line in common with a County, Town or State Line you
should be able to calculate the magnetic declination for the date when that
metes and bounds was written.