Land survey question: Adjustment on compass for magnetic north?
February 7, 2010 – 2:09 pmHow much adjustment must I use on a magnetic compass to account for the fluctuation of magnetic north in finding boundary points from a surveryor map made in 1978? How many degrees, plus or minus? Land is in Virginia, approx long -80, lat 37.
One Response to “Land survey question: Adjustment on compass for magnetic north?”
A web page about compass reading in Virginia (first link) says that the adjustment is -6° in the southwestern corner of Virginia and -11° on the coast.
A declination calculator at the National Geophysical Data Center’s site (second link) says the adjustment for your coordinates and the date of the map (using 1 Jan 1978) is "5° 12′ W changing by 0° 8′ W per year."
By Navigator on Feb 7, 2010