Unigine::Ellipsoid Class
| Header: | #include <UnigineEllipsoid.h> |
The Ellipsoid class handles the geodetic transformations:
- Specifies the Ellipsoid settings: semimajor axis, flattening coefficient
- Performs systems coordinates (ECF, ENU, NED, Geodetic) conversion
- Solves direct and inverse geodetic problems with different calculation mode (Great Circle and Vincenty algorithms)
This class is used to create an Ellipsoid instance to the GeodeticPivot class.
Here is a code snippet of the Ellipsoid class usage:
Source code (C++)
#include "UnigineMathLib.h"
#include "UnigineGeodetics.h"
#include "UnigineEllipsoid.h"
using namespace Unigine;
using namespace Unigine::Math;
/* ... */
// define the geodetic origin
dvec3 tomsk_origin = dvec3(58.49771, 84.97437, 117.0);
// create a new GeodeticPivot object
GeodeticPivotPtr pivot = GeodeticPivot::create();
// create a new ellipsoid and specify its settings
EllipsoidPtr ellipsoid = pivot->getEllipsoid();
ellipsoid->setSemimajorAxis(80000.0f);
ellipsoid->setMode(Ellipsoid::MODE_FAST);
// set the ellipsoid to the pivot
pivot->setOrigin(tomsk_origin);
pivot->setEllipsoid(ellipsoid);Ellipsoid Class
Members
static EllipsoidPtr create ( double semimajor_axis, double flattening ) #
Constructor. Creates a new Ellipsoid class instance with given flattening and semimajor axis.Arguments
- double semimajor_axis - Semimajor axis.
- double flattening - Flattening coefficient.
static EllipsoidPtr create ( ) #
Constructor. Creates a new Ellipsoid class instance (WGS84 Ellipsoid).Math::dvec3 getENUSurfacePoint ( const Math::dvec3 & geodetic_origin, const Math::dvec3 & tangent_point ) #
Returns surface point by using tangent point coordinates.Notice
The Up-axis (Z+) direction in ENU points upward along the ellipsoid normal, while in UNIGINE implementation of ENU it goes from the Earth's center.
Arguments
- const Math::dvec3 & geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
- const Math::dvec3 & tangent_point - Tangent point coordinates to converted (curved) to surface coordinates (offset related to point of junction).
Return value
Surface point coordinates.Math::dvec3 getENUTangentPoint ( const Math::dvec3 & geodetic_origin, const Math::dvec3 & surface_point ) #
Returns tangent point ENU coordinates based on the geographical coordinates.Notice
The Up-axis (Z+) direction in ENU points upward along the ellipsoid normal, while in UNIGINE implementation of ENU it goes from the Earth's center.
Arguments
- const Math::dvec3 & geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
- const Math::dvec3 & surface_point - Surface point coordinates to be converted (flatten) to tangent point (offset related to point of junction).
Return value
Tangent point coordinates.Math::quat getENUWorldRotation ( const Math::dvec3 & geodetic_origin ) #
Returns the world rotation quaternion in ENU coordinates.Notice
The Up-axis (Z+) direction in ENU points upward along the ellipsoid normal, while in UNIGINE implementation of ENU it goes from the Earth's center.
Arguments
- const Math::dvec3 & geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
Return value
World rotation in ENU coordinates.Math::dmat4 getENUWorldTransform ( const Math::dvec3 & geodetic_origin ) #
Returns the world transformation matrix in ENU coordinates.Notice
The Up-axis (Z+) direction in ENU points upward along the ellipsoid normal, while in UNIGINE implementation of ENU it goes from the Earth's center.
Arguments
- const Math::dvec3 & geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
Return value
World transformation matrix in ENU coordinates.void setFlattening ( double flattening ) #
Sets new flattening for the ellipsoid.Arguments
- double flattening - Flattening coefficient of the ellipsoid. If the value is 0, the ellipsoid has a sphere shape, for 1 the ellipsoid has a circle (completely flat) shape.
double getFlattening ( ) #
Returns flattening coefficient of the ellipsoid.Return value
Flattening coefficient of the ellipsoid.double getMeanRadius ( ) #
Returns the mean radius of the ellipsoid.Return value
The mean radius of the ellipsoid.int isSupported ( ) #
Returns a value indicating if the geodetics feature is enabled.Return value
1 if the geodetics feature is enabled; otherwise, 0.void setMode ( int mode ) #
Sets the calculation mode.Arguments
- int mode - The variable of the calculation mode. It can be one of the following:
int getMode ( ) #
Returns the calculation mode int value: 1 if the mode is MODE_ACCURATE, 0 if the mode is MODE_FAST.Return value
1 if the mode is MODE_ACCURATE, 0 if the mode is MODE_FAST.Math::dvec3 getNEDSurfacePoint ( const Math::dvec3 & geodetic_origin, const Math::dvec3 & tangent_point ) #
Returns surface point by using tangent point coordinates.Notice
The Down-axis direction in NED points downward along the ellipsoid normal, while in UNIGINE implementation of NED it goes through the Earth's center.
Arguments
- const Math::dvec3 & geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
- const Math::dvec3 & tangent_point - Tangent point coordinates to converted (curved) to surface coordinates (offset related to point of junction).
Return value
Surface point coordinates.Math::dvec3 getNEDTangentPoint ( const Math::dvec3 & geodetic_origin, const Math::dvec3 & surface_point ) #
Returns tangent point NED coordinates based on the geographical coordinates.Notice
The Down-axis direction in NED points downward along the ellipsoid normal, while in UNIGINE implementation of NED it goes through the Earth's center.
Arguments
- const Math::dvec3 & geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
- const Math::dvec3 & surface_point - Surface point coordinates to be converted (flatten) to tangent point (offset related to point of junction).
Return value
Tangent point coordinates.Math::quat getNEDWorldRotation ( const Math::dvec3 & geodetic_origin ) #
Returns the world rotation quaternion in NED coordinates.Notice
The Down-axis direction in NED points downward along the ellipsoid normal, while in UNIGINE implementation of NED it goes through the Earth's center.
Arguments
- const Math::dvec3 & geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
Return value
World rotation in NED coordinates.Math::dmat4 getNEDWorldTransform ( const Math::dvec3 & geodetic_origin ) #
Returns the world transformation matrix in NED coordinates.Notice
The Down-axis direction in NED points downward along the ellipsoid normal, while in UNIGINE implementation of NED it goes through the Earth's center.
Arguments
- const Math::dvec3 & geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
Return value
World transformation matrix in NED coordinates.void setSemimajorAxis ( double axis ) #
Sets new semimajor axis of the ellipsoid.Arguments
- double axis - Semimajor axis length in units.
double getSemimajorAxis ( ) #
Returns semimajor axis length of the ellipsoid in units.Return value
Semimajor axis of the ellipsoid.double getSemimajorEccentricitySqr ( ) #
Returns the squared eccentricity calculated along the semimajor axis.Return value
Squared eccentricity calculated along the semimajor axis.double getSemiminorAxis ( ) #
Returns semiminor axis of the ellipsoid in units.Return value
Semiminor axis of the ellipsoid in units.double getSemiminorEccentricitySqr ( ) #
Returns the squared eccentricity calculated along the semiminor axis.Return value
Squared eccentricity calculated along the semiminor axis.Math::dvec3 solveGeodeticDirect ( const Math::dvec3 & geodetic_start, double bearing, double distance ) #
Solves the direct geodetic problem: calculates end point coordinates on the ellipsoid by using given start point, distance between points, and bearing value.Arguments
- const Math::dvec3 & geodetic_start - Start point on the ellipsoid.
- double bearing - Bearing value.
- double distance - Distance between two points on the ellipsoid.
void solveGeodeticInverse ( const Math::dvec3 & geodetic_start, const Math::dvec3 & geodetic_end, double & bearing, double & distance ) #
Solves the inverse geodetic problem: calculates distance and bearing values by using given start and end points on the ellipsoid.Arguments
- const Math::dvec3 & geodetic_start - Start point on the ellipsoid.
- const Math::dvec3 & geodetic_end - End point on the ellipsoid.
- double & bearing - Variable to save the calculated bearing value.
- double & distance - Variable to save the calculated distance value.
Math::dvec3 toECF ( const Math::dvec3 & geodetic_coords ) #
Converts geodetic coordinates to Cartesian (ECF).Arguments
- const Math::dvec3 & geodetic_coords - Ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters)) to be converted to Cartesian.
Return value
Cartesian coordinates.Math::dvec3 toENU ( const Math::dvec3 & geodetic_origin, const Math::dvec3 & geodetic_coords ) #
Converts geodetic coordinates to ENU (East, North, Up).Notice
The Up-axis (Z+) direction in ENU points upward along the ellipsoid normal, while in UNIGINE implementation of ENU it goes from the Earth's center.
Arguments
- const Math::dvec3 & geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
- const Math::dvec3 & geodetic_coords - Coordinates to be converted to ENU.
Return value
ENU coordinates.Math::dvec3 toGeodetic ( const Math::dvec3 & ecf_coords, int need_alt = 1 ) #
Converts Cartesian (ECF) coordinates to Ellipsoid.Arguments
- const Math::dvec3 & ecf_coords - Cartesian ECF coordinates to be converted.
- int need_alt - Flag indicating if altitude is to be calculated. 1 to calculate altitude, 0 - to skip altitude calculation.The default value is 1.
Return value
Ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters)Math::dvec3 toNED ( const Math::dvec3 & geodetic_origin, const Math::dvec3 & geodetic_coords ) #
Converts geodetics coordinates to NED (North, East, Down).Notice
The Down-axis direction in NED points downward along the ellipsoid normal, while in UNIGINE implementation of NED it goes through the Earth's center.
Arguments
- const Math::dvec3 & geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
- const Math::dvec3 & geodetic_coords - Coordinates to be converted to NED.
Return value
NED coordinates.Last update:
01.04.2021
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