/* See LICENSE file for copyright and license details. */
#ifndef LIBTELLURIAN_H
#define LIBTELLURIAN_H
#if defined(__GNUC__)
# define LIBTELLURIAN_CONST__ __attribute__((__const__, __warn_unused_result__))
# define LIBTELLURIAN_WUR__ __attribute__((__warn_unused_result__))
#else
# define LIBTELLURIAN_CONST__
# define LIBTELLURIAN_WUR__
#endif
/**
* The Earth's equatorial radius, in meters
*/
#define LIBTELLURIAN_EQUATORIAL_RADIUS 6378137.0 /* a */
/**
* The Earth's polar radius, in meters
*/
#define LIBTELLURIAN_POLAR_RADIUS 6356752.314245 /* b */
/**
* The Earth's mean radius (arithmetic mean), in meters
*/
#define LIBTELLURIAN_MEAN_RADIUS 6371008.771415 /* (2a + b) / 3 */
/**
* The Earth's volumetric radius (geometric mean), in meters
*/
#define LIBTELLURIAN_VOLUMETRIC_RADIUS 6371000.7900090935 /* ∛(a² * b) */
/**
* The Earth's authalic radius (equal-area mean), in meters
*/
#define LIBTELLURIAN_AUTHALIC_RADIUS 6371007.180918414 /* √(a²/2 + (b² artanh e) / 2e) */
/**
* The Earth's rectifying radius, in meters
*/
#define LIBTELLURIAN_RECTIFYING_RADIUS 6367449.14582 /* 2π⁻¹∫{0 → ½π} √(a² cos² φ + b² sin² φ) dφ ≅ ∛(½(√a³+√b³))² */
/**
* The Earth's nominal equatorial radius, in meters
*/
#define LIBTELLURIAN_NOMINAL_EQUATORIAL_RADIUS 6378100.
/**
* The Earth's nominal polar radius, in meters
*/
#define LIBTELLURIAN_NOMINAL_POLAR_RADIUS 6356800.
/**
* The Earth's nominal radius, in meters
*/
#define LIBTELLURIAN_NOMINAL_RADIUS LIBTELLURIAN_NOMINAL_EQUATORIAL_RADIUS
/**
* The Earth's equatorial circumference, in meters
*/
#define LIBTELLURIAN_EQUATORIAL_CIRCUMFERENCE 40075016.68557849 /* 2bπ */
/**
* The Earth's meridional circumference, in meters
*/
#define LIBTELLURIAN_MERIDIONAL_CIRCUMFERENCE 39940652.74224401 /* 2bπ */
/**
* The Earth's mean circumference (arithmetic mean), in meters
*/
#define LIBTELLURIAN_MEAN_CIRCUMFERENCE 40030228.70446699 /* 2π(2a + b) / 3 */
/**
* The Earth's volumetric circumference (geometric mean), in meters
*/
#define LIBTELLURIAN_VOLUMETRIC_CIRCUMFERENCE 40030178.555814676 /* 2π∛(a² * b) */
/**
* The Earth's authalic circumference (equal-area mean), in meters
*/
#define LIBTELLURIAN_AUTHALIC_CIRCUMFERENCE 40030218.71108221 /* 2π√(a²/2 + (b² artanh e) / 2e) */
/**
* The Earth's rectifying circumference, in meters
*/
#define LIBTELLURIAN_RECTIFYING_CIRCUMFERENCE 40007862.91722943 /* 4 ∫{0 → ½π} √(a² cos² φ + b² sin² φ) dφ */
/**
* The Earth's gravity at the equator, in meters per square-second
*/
#define LIBTELLURIAN_EQUATORIAL_GRAVITY 9.7803253359
/**
* The Earth's gravity at the poles, in meters per square-second
*/
#define LIBTELLURIAN_POLAR_GRAVITY 9.8321849378
/**
* The Earth's normal gravity at the equator, in meters per square-second
*/
#define LIBTELLURIAN_NORMAL_EQUATORIAL_GRAVITY 9.7803267715
/**
* The Earth's normal gravity at the poles, in meters per square-second
*/
#define LIBTELLURIAN_NORMAL_POLAR_GRAVITY 9.8321863685
/**
* The Earth's mass, in kilograms
*/
#define LIBTELLURIAN_MASS_OF_EARTH 5.972168e24
/**
* Calculate the distance of the nominal sea level (geocentric
* radius), for some point on the Earth's surface, from the
* centre of the Earth
*
* @param latitude GPS latitude coordinate, in degrees
* @return The geocentric altitude of the sea level, in meters
*/
LIBTELLURIAN_CONST__
double libtellurian_sea_level(double latitude);
/**
* Calculate the distance of the nominal sea level (geocentric
* radius), for some point on the Earth's surface, from the
* centre of the Earth
*
* @param latitude GPS latitude coordinate, in radians
* @return The geocentric altitude of the sea level, in meters
*/
LIBTELLURIAN_CONST__
double libtellurian_sea_level_radians(double latitude);
/**
* Calculate the distance between two points on the Earth's surface
*
* This function is gives an approximate value using
* a sphere as a model for the Earth
*
* @param latitude1 GPS latitude coordinate for the first point, in degrees
* @param longitude1 GPS longitude coordinate for the first point, in degrees
* @param latitude2 GPS latitude coordinate for the second point, in degrees
* @param longitude2 GPS longitude coordinate for the second point, in degrees
* @return Approximate distance between the two points
*/
LIBTELLURIAN_CONST__
double libtellurian_coarse_distance(double latitude1, double longitude1,
double latitude2, double longitude2);
/**
* Calculate the distance between two points on the Earth's surface
*
* This function is gives an approximate value using
* a sphere as a model for the Earth
*
* @param latitude1 GPS latitude coordinate for the first point, in radians
* @param longitude1 GPS longitude coordinate for the first point, in radians
* @param latitude2 GPS latitude coordinate for the second point, in radians
* @param longitude2 GPS longitude coordinate for the second point, in radians
* @return Approximate distance between the two points
*/
LIBTELLURIAN_CONST__
double libtellurian_coarse_distance_radians(double latitude1, double longitude1,
double latitude2, double longitude2);
/**
* Calculate the distance and azimuths between two points on the Earth's surface
*
* This function is gives good approximate values
* using an oblate spheroid as a model for the Earth
*
* @param latitude1 GPS latitude coordinate for the first point, in degrees
* @param longitude1 GPS longitude coordinate for the first point, in degrees
* @param latitude2 GPS latitude coordinate for the second point, in degrees
* @param longitude2 GPS longitude coordinate for the second point, in degrees
* @param azimuth1_out Output parameter for the forward azimuth, in degrees,
* at the first point; or `NULL`
* @param azimuth2_out Output parameter for the forward azimuth, in degrees,
* at the second point; or `NULL`
* @return Approximate distance between the two points
*
* Calculating the the forward azimuths is not free, but it
* is cheap to compute them (especially the first one) when
* most of the computations for the distance have been
* performed. If you have no need for an azimuth you can set
* the corresponding output parameter to `NULL`, and the
* function will not compute it.
*/
LIBTELLURIAN_WUR__
double libtellurian_distance(double latitude1, double longitude1,
double latitude2, double longitude2,
double *azimuth1_out, double *azimuth2_out);
/**
* Calculate the distance and azimuths between two points on the Earth's surface
*
* This function is gives good approximate values
* using an oblate spheroid as a model for the Earth
*
* @param latitude1 GPS latitude coordinate for the first point, in radians
* @param longitude1 GPS longitude coordinate for the first point, in radians
* @param latitude2 GPS latitude coordinate for the second point, in radians
* @param longitude2 GPS longitude coordinate for the second point, in radians
* @param azimuth1_out Output parameter for the forward azimuth, in radians,
* at the first point; or `NULL`
* @param azimuth2_out Output parameter for the forward azimuth, in radians,
* at the second point; or `NULL`
* @return Approximate distance between the two points
*
* Calculating the the forward azimuths is not free, but it
* is cheap to compute them (especially the first one) when
* most of the computations for the distance have been
* performed. If you have no need for an azimuth you can set
* the corresponding output parameter to `NULL`, and the
* function will not compute it.
*/
LIBTELLURIAN_WUR__
double libtellurian_distance_radians(double latitude1, double longitude1,
double latitude2, double longitude2,
double *azimuth1_out, double *azimuth2_out);
/**
* Calculate the azimuths between two points on the Earth's surface
*
* This function is gives good approximate values
* using an oblate spheroid as a model for the Earth
*
* @param latitude1 GPS latitude coordinate for the first point, in degrees
* @param longitude1 GPS longitude coordinate for the first point, in degrees
* @param latitude2 GPS latitude coordinate for the second point, in degrees
* @param longitude2 GPS longitude coordinate for the second point, in degrees
* @param azimuth1_out Output parameter for the forward azimuth, in degrees,
* at the first point; or `NULL`
* @param azimuth2_out Output parameter for the forward azimuth, in degrees,
* at the second point; or `NULL`
*
* This function is identical to libtellurian_distance`
* except it does not compute the distance between the
* points
*/
void libtellurian_azimuth(double latitude1, double longitude1,
double latitude2, double longitude2,
double *azimuth1_out, double *azimuth2_out);
/**
* Calculate the azimuths between two points on the Earth's surface
*
* This function is gives good approximate values
* using an oblate spheroid as a model for the Earth
*
* @param latitude1 GPS latitude coordinate for the first point, in radians
* @param longitude1 GPS longitude coordinate for the first point, in radians
* @param latitude2 GPS latitude coordinate for the second point, in radians
* @param longitude2 GPS longitude coordinate for the second point, in radians
* @param azimuth1_out Output parameter for the forward azimuth, in radians,
* at the first point; or `NULL`
* @param azimuth2_out Output parameter for the forward azimuth, in radians,
* at the second point; or `NULL`
*
*
* This function is identical to libtellurian_distance_radians`
* except it does not compute the distance between the points
*/
void libtellurian_azimuth_radians(double latitude1, double longitude1,
double latitude2, double longitude2,
double *azimuth1_out, double *azimuth2_out);
/**
* Calculate the location that is some distance away,
* in some direction, from some point
*
* @param latitude1 GPS latitude coordinate for the starting point, in degrees
* @param longitude1 GPS longitude coordinate for the starting point, in degrees
* @param azimuth1 The direction to travel, in degrees
* @param distance The distance to travel, in meters
* @param latitude2_out Output parameter for the end point's GPS latitude
* coordinate, in degrees; or `NULL`
* @param longitude2_out Output parameter for the end point's GPS longitude
* coordinate, in degrees; or `NULL`
* @param azimuth2_out Output parameter for the direction from the end point
* to the starting point, in degrees; or `NULL`
*/
void libtellurian_end_point(double latitude1, double longitude1, double azimuth1, double distance,
double *latitude2_out, double *longitude2_out, double *azimuth2_out);
/**
* Calculate the location that is some distance away,
* in some direction, from some point
*
* @param latitude1 GPS latitude coordinate for the starting point, in radians
* @param longitude1 GPS longitude coordinate for the starting point, in radians
* @param azimuth1 The direction to travel, in radians
* @param distance The distance to travel, in meters
* @param latitude2_out Output parameter for the end point's GPS latitude
* coordinate, in radians; or `NULL`
* @param longitude2_out Output parameter for the end point's GPS longitude
* coordinate, in radians; or `NULL`
* @param azimuth2_out Output parameter for the direction from the end point
* to the starting point, in radians; or `NULL`
*/
void libtellurian_end_point_radians(double latitude1, double longitude1, double azimuth1, double distance,
double *latitude2_out, double *longitude2_out, double *azimuth2_out);
/**
* Calculate the normal gravity for some point on
* the Earth's surface, where the Earth's is model
* as an oblate spheroid
*
* @param latitude GPS latitude coordinate, in degrees
* @return The normal gravity, in meters per square-second
*/
LIBTELLURIAN_CONST__
double libtellurian_normal_gravity(double latitude);
/**
* Calculate the normal gravity for some point on
* the Earth's surface, where the Earth's is model
* as an oblate spheroid
*
* @param latitude GPS latitude coordinate, in radians
* @return The normal gravity, in meters per square-second
*/
LIBTELLURIAN_CONST__
double libtellurian_normal_gravity_radians(double latitude);
/**
* Calculate the gravity adjusted for the elevation
* above the altitude where the gravity is measure
*
* Altitudes above circa 100000 meters is out of range
* for this function (that would be in outer space)
*
* @param gravity The gravity at sea level, in meters per square-second
* @param latitude GPS latitude coordinate, in degrees
* @param altitude Elevation above the gravity's measurement point, in meters
* @return The height-adjusted gravity, in meters per square-second
*/
LIBTELLURIAN_CONST__
double libtellurian_elevated_gravity(double gravity, double latitude, double altitude);
/**
* Calculate the gravity adjusted for the elevation
* above the altitude where the gravity is measure
*
* Altitudes above circa 100000 meters is out of range
* for this function (that would be in outer space)
*
* @param gravity The gravity at sea level, in meters per square-second
* @param latitude GPS latitude coordinate, in radians
* @param altitude Elevation above the gravity's measurement point, in meters
* @return The height-adjusted gravity, in meters per square-second
*/
LIBTELLURIAN_CONST__
double libtellurian_elevated_gravity_radians(double gravity, double latitude, double altitude);
/**
* Calculate the Earth's meridan radius of curvature at some latitude
*
* @param latitude GPS latitude coordinate, in degrees
* @return The meridan radius of curvature, in meters (for radians!)
*/
LIBTELLURIAN_CONST__
double libtellurian_meridan_radius(double latitude);
/**
* Calculate the Earth's meridan radius of curvature at some latitude
*
* @param latitude GPS latitude coordinate, in radians
* @return The meridan radius of curvature, in meters (for radians)
*/
LIBTELLURIAN_CONST__
double libtellurian_meridan_radius_radians(double latitude);
/**
* Calculate the Earth's transverse radius of curvature at some latitude
*
* @param latitude GPS latitude coordinate, in degrees
* @return The transverse radius of curvature, in meters (for radians!)
*/
LIBTELLURIAN_CONST__
double libtellurian_transverse_radius(double latitude);
/**
* Calculate the Earth's transverse radius of curvature at some latitude
*
* @param latitude GPS latitude coordinate, in radians
* @return The transverse radius of curvature, in meters (for radians)
*/
LIBTELLURIAN_CONST__
double libtellurian_transverse_radius_radians(double latitude);
/**
* Calculate the Earth's azimuthal radius of curvature
* at some latitude for some azimuth
*
* @param latitude GPS latitude coordinate, in degrees
* @param azimuth The azimuth, in degrees
* @return The transverse radius of curvature, in meters (for radians!)
*/
LIBTELLURIAN_CONST__
double libtellurian_azimuthal_radius(double latitude, double azimuth);
/**
* Calculate the Earth's azimuthal radius of curvature
* at some latitude for some azimuth
*
* @param latitude GPS latitude coordinate, in radians
* @param azimuth The azimuth, in radians
* @return The transverse radius of curvature, in meters (for radians)
*/
LIBTELLURIAN_CONST__
double libtellurian_azimuthal_radius_radians(double latitude, double azimuth);
/**
* Calculate the Earth's Gaussian radius of curvature at some latitude
*
* @param latitude GPS latitude coordinate, in degrees
* @return The Gaussian radius of curvature, in meters (for radians!)
*/
LIBTELLURIAN_CONST__
double libtellurian_gaussian_radius(double latitude);
/**
* Calculate the Earth's Gaussian radius of curvature at some latitude
*
* @param latitude GPS latitude coordinate, in radians
* @return The Gaussian radius of curvature, in meters (for radians)
*/
LIBTELLURIAN_CONST__
double libtellurian_gaussian_radius_radians(double latitude);
#undef LIBTELLURIAN_CONST__
#undef LIBTELLURIAN_WUR__
#endif
