|PR/VI North-South Deflections (DEFLEC96)
|This 2’ surface deflection of the vertical grid for Puerto Rico and the Virgin Islands
is distributed as the DEFLEC96 model. The computation used about 26,000 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 Defence Mapping 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 1971IGSN71). The deflections are referred to theGeodetic Reference System 1980
(GRS80) ellipsoidal normals. The curvature of the plumbline correction has been applied.
We are particularly grateful to NGA (former National Imagery and Mapping Agency) for
theirassistance and their data contributions.