Ellipsoid Class

Geodetic Class

Members

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Ellipsoid ()

Constructor. Creates a new Ellipsoid class instance (WGS84 Ellipsoid).

Ellipsoid (double semimajor_axis, double flattening)

Constructor. Creates a new Ellipsoid class instance with given semi-major axis and flattening.

Arguments

• double semimajor_axis - Semimajor axis (the longest radius) of the ellipsoid.
• double flattening - Flattening of a sphere. If the value is 0, the ellipsoid has a sphere shape, for 1 the ellipsoid has a circle (completely flat) shape.

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 getSemiminorAxis ()

Returns semiminor axis of the ellipsoid in units.

Return value

Semiminor axis of the ellipsoid in units.

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 getSemimajorEccentricitySqr ()

Returns the squared eccentricity calculated along the semimajor axis.

Return value

Squared eccentricity calculated along the semimajor axis.

double getSemiminorEccentricitySqr ()

Returns the squared eccentricity calculated along the semiminor axis.

Return value

Squared eccentricity calculated along the semiminor axis.

void setMode (int mode)

Sets the calculation mode.

Arguments

• int mode - The variable of the calculation mode. It can be one of the following:
  • MODE_FAST
  • MODE_ACCURATE

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.

double getMeanRadius ()

Returns the mean radius of the ellipsoid.

Return value

The mean radius of the ellipsoid.

vec3 getENUTangentPoint (dvec3 geodetic_origin, vec3 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).
• vec3 surface_point - Surface coordinates to be converted (flatten) to tangent (related to origin).

Return value

Tangent coordinates.

vec3 getENUSurfacePoint (dvec3 geodetic_origin, vec3 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).
• vec3 tangent_point - Tangent point coordinates to converted (curved) to surface coordinates (offset related to point of junction).

Return value

Surface 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.

vec3 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.

vec3 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.

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.

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 toGeodetic (dvec3 ecf_coords)

Converts Cartesian (ECF) coordinates to Ellipsoid.

Arguments

• dvec3 ecf_coords - Cartesian ECF coordinates to be converted.

Return value

Ellipsoid coordinates (latitude (degrees), longitude (degrees) and altitude (meters)

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 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.

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int ELLIPSOID_MODE_FAST

Description

A calculation mode is computed by using Great-circle distance formula. It works pretty fast, but you'll get positioning errors on big (~80000x80000 units) distances.

int ELLIPSOID_MODE_ACCURATE

Description

A calculation mode uses Vincenty's formula to calculate distances on the surface of the ellipsoid with a millimeter precision. It takes more time for calculation, but the accuracy of positioning is awesome.