|Alaska North-South Deflections (DEFLEC96)
|This 2’ x 4’ surface deflection of the vertical grid for Alaska is the DEFLEC96 model.
The computation used about 1.1 million terrestrial and marine gravity data held in
the National Geodetic Survey gravity data base in July 1996. These data were augmented
by gravity data contributions from NGA (former National Imagery and Mapping Agency)
(former DefenseMapping Agency). The deflections were obtained by numerical differentiation
of cubic spline models along the meridians of the GEOID96 grid. The gravity values
are based on the International Gravity Standardization Net 1971 (IGSN71). The deflections
are referred to the Geodetic Reference System 1980 (GRS80) ellipsoidal normals. The
curvature of the plumb line correction has been applied.Additional information is
available at:http://www.ngs.noaa.gov/ We are particularlygrateful to NGA (former National
Imagery and Mapping Agency) for their assistance and their data contributions.