Ellipsoid Class
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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 (UnigineScript)
// define the geodetic origin
dvec3 tomsk_origin = 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
Members
static 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.
static 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.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.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.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.Arguments
- 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.dvec3 getNEDSurfacePoint ( dvec3 geodetic_origin, dvec3 tangent_point ) #
Returns surface point by using tangent point coordinates.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.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.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.Arguments
- 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.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, 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
- dvec3 geodetic_start - Start point on the ellipsoid.
- 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.
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).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).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:
2020-04-27
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