Public Member Functions
double	eccentricity () const

double	inverseFlattening () const

bool	isIvfDefinitive () const

bool	isSphere () const

double	orthodromicDistance (double x1, double y1, double x2, double y2)

double	radiusOfCurvature (double latitude)

double	semiMajorAxis () const

double	semiMinorAxis () const

Static Public Member Functions
static Ellipsoid	CLARKE_1866 ()

static Ellipsoid	createEllipsoid (const QString &name, double semiMajorAxis, double semiMinorAxis)

static Ellipsoid	createFlattenedSphere (const QString &name, double semiMajorAxis, double inverseFlattening)

static Ellipsoid	GRS80 ()

static Ellipsoid	INTERNATIONAL_1924 ()

static Ellipsoid	SPHERE ()

static Ellipsoid	WGS84 ()

Protected Member Functions
	Ellipsoid (const QString &name, double radius, bool ivfDefinitive)

	Ellipsoid (const QString &name, double semiMajorAxis, double semiMinorAxis, double inverseFlattening, bool ivfDefinitive)

Protected Attributes
double	m_inverseFlattening

bool	m_isSphere

bool	m_ivfDefinitive

double	m_semiMajorAxis

double	m_semiMinorAxis

QString	name

Detailed Description

Geometric figure that can be used to describe the approximate shape of the earth. In mathematical terms, it is a surface formed by the rotation of an ellipse about its minor axis. An ellipsoid requires two defining parameters:

semi-major axis and inverse flattening, or
semi-major axis and semi-minor axis.

Constructor & Destructor Documentation

◆ Ellipsoid() [1/2]

Digikam::Ellipsoid::Ellipsoid	(	const QString &	name,
		double	semiMajorAxis,
		double	semiMinorAxis,
		double	inverseFlattening,
		bool	ivfDefinitive
	)

protected

Constructs a new ellipsoid using the specified axis length. The properties map is given unchanged to the AbstractIdentifiedObjectAbstractIdentifiedObject(Map) super-class constructor.

Parameters

semiMajorAxis	The equatorial radius.
semiMinorAxis	The polar radius.
inverseFlattening	The inverse of the flattening value.
ivfDefinitive	`true` if the inverse flattening is definitive.

See also: createEllipsoid; createFlattenedSphere

Referenced by createEllipsoid(), and createFlattenedSphere().

◆ Ellipsoid() [2/2]

Digikam::Ellipsoid::Ellipsoid	(	const QString &	name,
		double	radius,
		bool	ivfDefinitive
	)

protected

Member Function Documentation

◆ CLARKE_1866()

Ellipsoid Digikam::Ellipsoid::CLARKE_1866 ( )

static

Clarke 1866 ellipsoid with axis in metres.

References createFlattenedSphere().

◆ createEllipsoid()

Ellipsoid Digikam::Ellipsoid::createEllipsoid	(	const QString &	name,
		double	semiMajorAxis,
		double	semiMinorAxis
	)

static

Constructs a new ellipsoid using the specified axis length.

Parameters

name	The ellipsoid name.
semiMajorAxis	The equatorial radius.
semiMinorAxis	The polar radius.

References Ellipsoid(), m_semiMajorAxis, m_semiMinorAxis, and name.

Referenced by SPHERE().

◆ createFlattenedSphere()

Ellipsoid Digikam::Ellipsoid::createFlattenedSphere	(	const QString &	name,
		double	semiMajorAxis,
		double	inverseFlattening
	)

static

Constructs a new ellipsoid using the specified axis length and inverse flattening value.

Parameters

name	The ellipsoid name.
semiMajorAxis	The equatorial radius.
inverseFlattening	The inverse flattening value. values.

References DBL_MAX, Ellipsoid(), m_inverseFlattening, m_semiMajorAxis, and name.

Referenced by CLARKE_1866(), GRS80(), INTERNATIONAL_1924(), and WGS84().

◆ eccentricity()

double Digikam::Ellipsoid::eccentricity ( ) const

The ratio of the distance between the center and a focus of the ellipse to the length of its semimajor axis. The eccentricity can alternately be computed from the equation: e=sqrt(2f-f^2).

References m_isSphere, m_semiMajorAxis, and m_semiMinorAxis.

Referenced by radiusOfCurvature().

◆ GRS80()

Ellipsoid Digikam::Ellipsoid::GRS80 ( )

static

GRS 80 ellipsoid with axis in metres.

References createFlattenedSphere().

◆ INTERNATIONAL_1924()

Ellipsoid Digikam::Ellipsoid::INTERNATIONAL_1924 ( )

static

International 1924 ellipsoid with axis in metres.

References createFlattenedSphere().

◆ inverseFlattening()

double Digikam::Ellipsoid::inverseFlattening ( ) const

Returns the value of the inverse of the flattening constant. Flattening is a value used to indicate how closely an ellipsoid approaches a spherical shape. The inverse flattening is related to the equatorial/polar radius by the formula

ivf=r_e/(r_e-r_p).

For perfect spheres (i.e. if isSphere returns true), the DoublePOSITIVE_INFINITY value is used.

Returns: The inverse flattening value.

References m_inverseFlattening.

◆ isIvfDefinitive()

bool Digikam::Ellipsoid::isIvfDefinitive ( ) const

Indicates if the inverse flattening is definitive for this ellipsoid. Some ellipsoids use the IVF as the defining value, and calculate the polar radius whenever asked. Other ellipsoids use the polar radius to calculate the IVF whenever asked. This distinction can be important to avoid floating-point rounding errors.

Returns: true if the inverse flattening is definitive, or false if the polar radius is definitive.

References m_ivfDefinitive.

◆ isSphere()

bool Digikam::Ellipsoid::isSphere ( ) const

true if the ellipsoid is degenerate and is actually a sphere. The sphere is completely defined by the semi-major axis, which is the radius of the sphere.

Returns: true if the ellipsoid is degenerate and is actually a sphere.

References m_semiMajorAxis, and m_semiMinorAxis.

◆ orthodromicDistance()

double Digikam::Ellipsoid::orthodromicDistance	(	double	x1,
		double	y1,
		double	x2,
		double	y2
	)

Returns the orthodromic distance between two geographic coordinates. The orthodromic distance is the shortest distance between two points on a sphere's surface. The orthodromic path is always on a great circle. This is different from the loxodromic distance, which is a longer distance on a path with a constant direction on the compass.

Parameters

x1	Longitude of first point (in decimal degrees).
y1	Latitude of first point (in decimal degrees).
x2	Longitude of second point (in decimal degrees).
y2	Latitude of second point (in decimal degrees).