.TH LIBTELLURIAN_NORMAL_GRAVITY 3 libtellurian
.SH NAME
libtellurian_normal_gravity \- Calculate normal gravity

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

double libtellurian_normal_gravity(double \fIlatitude\fP);

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

.SH DESCRIPTION
The
.BR libtellurian_normal_gravity ()
function models the Earth as a spheroid and calculates
the normal (theoretical) gravity for any point on a given
.I latitude
at the surface. This acceleration does not account for
the angular velocity of the Earth's rotation.
.PP
The
.I latitude
shall be specified according to GPS and in degrees.
.PP
The
.BR libtellurian_normal_gravity_radians ()
function is identical to the
.BR libtellurian_normal_gravity ()
function except that
.I latitude
shall be specified in radians.

.SH RETURN VALUE
The
.BR libtellurian_normal_gravity ()
and
.BR libtellurian_normal_gravity_radians ()
functions return the normal gravity, at the specified
latitude, measured in meters per square second.

.SH ERRORS
None.

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