North-central N.H. '68 (NH)

Survey type M-Dz (magnetic; digitized from contour maps)
Flown by USGS
Date flown 05/68
Line spacing 0.8 (km)
Altitude 1524 (m) by barometer measurement
Total distance 2,503 (km)
References
Counties Oxford - Carroll - Coos - Grafton
Overlapping surveys

Data: Magnetic (M-Dz)