Northern Washington (WA)

Survey type M-Dz (magnetic; digitized from contour maps)
Flown by U.S. Geological Survey
Date flown 05/76
Line spacing 1.6 (km)
Altitude 2896 (m) by barometer measurement
Total distance 5,349 (km)
References
Counties Chelan - Okanogan - Skagit - Whatcom
Overlapping surveys

Data: Magnetic (M-Dz)