DEFLEC96
DEFLEC96 is a companion product derived from
GEOID96.
The geoid is a
surface of constant potential which conforms to sea level in an average
sense. Deflections of the vertical are the slopes associated with the
Earth's equipotential layers. The deflection of the vertical is the
departure a plumb bob would take from vertical defined by an ideal
ellipsoidal Earth. These quantities are typically a few arc seconds,
but can reach an arc minute of departure.
Deflections are used to relate the orientation of a locally-leveled
instrument, such as a theodolite, to a spatial reference system.
Important uses are corrections to zenith distance (vertical angle)
measurements, and the conversion between astronomic and ellipsoidal
azimuths (the Laplace correction).
PC Software
Interactive Computation of DEFLEC96 deflections
Full Size Image, DEFLEC96 Model
Images of Terrain, Gravity, Geoid, and Deflections
Geoid, Gravity, Deflection, and Data Coverage Grids
Frequently Asked Questions
On-Line Papers
The Geoid Research Page
Got a question?
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