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normalgravity.3
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normalgravity.3
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.TH "normalgravity" "1" "2021-02-15" "Fortran 95" "SHTOOLS 4.11"
.hy
.SH NormalGravity
.PP
Calculate the normal gravity on a flattened ellipsoid in geocentric
coordinates using the formula of Somigliana.
.SH Usage
.PP
\f[V]value\f[R] = NormalGravity (\f[V]geocentriclat\f[R], \f[V]gm\f[R],
\f[V]omega\f[R], \f[V]a\f[R], \f[V]b\f[R])
.SH Parameters
.TP
\f[V]value\f[R] : output, real(dp)
The normal gravity in SI units.
.TP
\f[V]geocentriclat\f[R]: input, real(dp)
Geocentric latitude in degrees.
.TP
\f[V]gm\f[R] : input, real(dp)
The gravitational constant multiplied by the mass of the planet.
.TP
\f[V]omega\f[R] : input, real(dp)
The angular rotation rate of the planet.
.TP
\f[V]a\f[R] : input, real(dp)
The semi-major axis of the flattened ellipsoid on which the normal
gravity is computed.
.TP
\f[V]b\f[R] : input, real(dp)
The semi-minor axis of the flattened ellipsoid on which the normal
gravity is computed.
.SH Description
.PP
\f[V]NormalGravity\f[R] will calculate the magnitude of the predicted
gravity (in m/s\[ha]2) on a flattened ellipsoid using Somigliana\[cq]s
formula.
The latitude is input in geocentric coordinates in degrees, which is
later converted to geodetic coordinates in the routine for use with
Somigliana\[cq]s formula.
Other input parameters include \f[V]gm\f[R], the product of the
gravitational constant and the planet\[cq]s mass, and the semi-major and
semi-minor axes of the planet, \f[V]a\f[R] and \f[V]b\f[R],
respectively.
For further details, see sections 2.7 and 2.8 of Physical Geodesy
(Hofmann-Wellenhof and Moritz).
.SH References
.PP
Hofmann-Wellenhof B, and H.
Moritz, \[lq]Physical Geodesy,\[rq] second edition, Springer, Wien, 403
pp., 2006.
.SH See also
.PP
makegravgriddh, makegeoidgrid