Unigine.Ellipsoid Class
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#)
// define the geodetic origin
dvec3 tomsk_origin = new dvec3(58.49771, 84.97437, 117.0);
// create a new GeodeticPivot object
GeodeticPivot pivot = new GeodeticPivot();
// create a new ellipsoid and specify its settings
Ellipsoid 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
Properties
double SemiminorEccentricitySqr#
The squared eccentricity calculated along the semiminor axis.
double SemimajorEccentricitySqr#
The squared eccentricity calculated along the semimajor axis.
double MeanRadius#
The mean radius of the ellipsoid.
double SemiminorAxis#
The Semiminor axis of the ellipsoid in units.
int Mode#
The calculation mode int value: 1 if the mode is MODE_ACCURATE, 0 if the mode is MODE_FAST.
double Flattening#
The Flattening coefficient of the ellipsoid.
double SemimajorAxis#
The Semimajor axis length of the ellipsoid in units.
Members
Ellipsoid ( 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.
Ellipsoid ( ) #
Constructor. Creates a new Ellipsoid class instance (WGS84 Ellipsoid).dvec3 GetENUSurfacePoint ( dvec3 geodetic_origin, 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
- dvec3 geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
- dvec3 tangent_point - Tangent point coordinates to converted (curved) to surface coordinates (offset related to point of junction).
Return value
Surface point coordinates.dvec3 GetENUTangentPoint ( dvec3 geodetic_origin, 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
- dvec3 geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
- dvec3 surface_point - Surface point coordinates to be converted (flatten) to tangent point (offset related to point of junction).
Return value
Tangent point coordinates.quat GetENUWorldRotation ( 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
- dvec3 geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
Return value
World rotation in ENU coordinates.dmat4 GetENUWorldTransform ( 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
- dvec3 geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
Return value
World transformation matrix in ENU coordinates.int IsSupported ( ) #
Returns a value indicating if the geodetics feature is enabled.Return value
1 if the geodetics feature is enabled; otherwise, 0.dvec3 GetNEDSurfacePoint ( dvec3 geodetic_origin, 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
- dvec3 geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
- dvec3 tangent_point - Tangent point coordinates to converted (curved) to surface coordinates (offset related to point of junction).
Return value
Surface point coordinates.dvec3 GetNEDTangentPoint ( dvec3 geodetic_origin, 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
- dvec3 geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
- dvec3 surface_point - Surface point coordinates to be converted (flatten) to tangent point (offset related to point of junction).
Return value
Tangent point coordinates.quat GetNEDWorldRotation ( 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
- dvec3 geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
Return value
World rotation in NED coordinates.dmat4 GetNEDWorldTransform ( 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
- dvec3 geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
Return value
World transformation matrix in NED coordinates.dvec3 SolveGeodeticDirect ( 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
- dvec3 geodetic_start - Start point on the ellipsoid.
- double bearing - Bearing value.
- double distance - Distance between two points on the ellipsoid.
void SolveGeodeticInverse ( dvec3 geodetic_start, dvec3 geodetic_end, out double bearing, out double distance ) #
Solves the inverse geodetic problem: calculates distance and bearing values by using given start and end points on the ellipsoid.Arguments
- dvec3 geodetic_start - Start point on the ellipsoid.
- dvec3 geodetic_end - End point on the ellipsoid.
- out double bearing - Variable to save the calculated bearing value.
- out double distance - Variable to save the calculated distance value.
dvec3 ToECF ( dvec3 geodetic_coords ) #
Converts geodetic coordinates to Cartesian (ECF).Arguments
- dvec3 geodetic_coords - Ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters)) to be converted to Cartesian.
Return value
Cartesian coordinates.dvec3 ToENU ( dvec3 geodetic_origin, 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
- dvec3 geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
- dvec3 geodetic_coords - Coordinates to be converted to ENU.
Return value
ENU coordinates.dvec3 ToGeodetic ( dvec3 ecf_coords, int need_alt = 1 ) #
Converts Cartesian (ECF) coordinates to Ellipsoid.Arguments
- 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)dvec3 ToNED ( dvec3 geodetic_origin, 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
- dvec3 geodetic_origin - The origin in ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters).
- dvec3 geodetic_coords - Coordinates to be converted to NED.
Return value
NED coordinates.Last update:
2021-04-01
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