.TH LIBTELLURIAN_EFFECTIVE_GRAVITY 3 libtellurian
.SH NAME
libtellurian_effective_gravity \- Calculate effective gravity

.SH SYNPOSIS
.nf
#include <libtellurian.h>

double libtellurian_effective_gravity(double \fIgravity\fP, double \fIlatitude\fP);

double libtellurian_effective_gravity_radians(double \fIgravity\fP, double \fIlatitude\fP);
.fi
.PP
Link with
.I -ltellurian
.IR -lm .

.SH DESCRIPTION
The
.BR libtellurian_effective_gravity ()
function models the Earth as a spheroid and calculates
the effective gravity for any point on a given
.I latitude
at the surface and the normal
.I gravity
at this point. This is an adjustment based on the
centrifugal force at the given latitude due to the
rotation of the Earth.
.PP
The
.I latitude
shall be specified according to GPS and in degrees,
and the normal
.I gravity
shall be specified in meters per square second.
.PP
The
.BR libtellurian_effective_gravity_radians ()
function is identical to the
.BR libtellurian_effective_gravity ()
function except that
.I latitude
shall be specified in radians.

.SH RETURN VALUE
The
.BR libtellurian_effective_gravity ()
and
.BR libtellurian_effective_gravity_radians ()
functions return the effective gravity, at the specified
latitude, measured in meters per square second.

.SH ERRORS
None.

.SH SEE ALSO
.BR libtellurian (7),
.BR libtellurian_normal_gravity (3),
.BR libtellurian_elevated_gravity (3)