Defines the Transverse Mercator projection. More...

#include <ilviews/maps/projection/tranmerc.h>

Inheritance diagram for IlvTransverseMercatorProjection:

Public Member Functions
	IlvTransverseMercatorProjection (IlDouble latitudeOfTrueScale=0.)
	This constructor initializes a new `IlvTransverseMercatorProjection` instance and sets the latitude of the true scale. More...

virtual IlvMapsError	forward (const IlvCoordinate &llIn, IlvCoordinate &xyOut) const
	Converts a latitude and a longitude to Cartesian coordinates (x, y). More...

virtual IlvMapsError	forward (const IlvCoordinate &llIn, IlvCoordinate &xyOut) const
	Converts a latitude and a longitude to Cartesian coordinates (x, y). More...

virtual IlvMapsError	forward (IlvCoordinate &coords) const
	Projects a latitude and a longitude pair to Cartesian coordinates. More...

IlDouble	getScaleFactor () const
	Returns the scale factor applied to the central meridian. More...

virtual IlvMapsError	inverse (const IlvCoordinate &xyIn, IlvCoordinate &llOut) const
	Converts the specified coordinate to a latitude and a longitude. More...

virtual IlvMapsError	inverse (const IlvCoordinate &xyIn, IlvCoordinate &llOut) const
	Converts the specified coordinate to a latitude and a longitude. More...

virtual IlvMapsError	inverse (IlvCoordinate &coords) const
	Invserse-projects Cartesian coordinates to a latitude and a longitude. More...

virtual IlvMapsError	setEllipsoid (const IlvEllipsoid &)
	Sets the ellipsoid used for the projection. More...

virtual void	setLLCenter (IlDouble, IlDouble)
	Specifies the central meridian and the central parallel (in radian) associated with the projection. More...

virtual void	setScaleFactor (IlDouble k0)
	Sets the scale factor applied to the central meridian. More...

virtual void	setXYOffset (IlDouble x0, IlDouble y0)
	Specifies the false easting and the false northing. More...

virtual void	write (IlvOutputFile &) const
	Saves the parameters of a projection to the specified output file. More...

Public Member Functions inherited from IlvProjection
virtual IlvProjection *	copy () const =0
	Returns a copy of the projection. More...

virtual IlvMapsError	forward (IlvCoordinate &coords) const
	Projects a latitude and a longitude pair to Cartesian coordinates. More...

IlDouble	getCentralMeridian () const
	Returns the central meridian of the projection. More...

IlDouble	getCentralParallel () const
	Returns the central parallel of the projection. More...

virtual IlvProjectionClassInfo *	getClassInfo () const
	Returns the class information for the projection. More...

const IlvHorizontalDatum *	getDatum (void) const
	Returns the horizontal datum used for the projection. More...

const IlvEllipsoid *	getEllipsoid () const
	Returns the ellipsoid used for the projection. More...

IlvMapsError	getError () const
	Returns the status of the projection. More...

IlDouble	getFalseEasting () const
	Returns the false easting of the projection. More...

IlDouble	getFalseNorthing () const
	Returns the false northing of the projection. More...

IlvProjectionInterface *	getInterface ()
	Returns the interface of the projection. More...

IlvCoordinate	getLLCenter (void) const
	Returns the central meridian and the central parallel associated with the projection (0-0 by default). More...

IlvProjectionGeometricProperty	getProperty () const
	Returns the geometric property of the projection. More...

const IlvUnitConverter *	getUnitConverter () const
	Returns the unit converter. More...

IlvCoordinate	getXYOffset () const
	Returns the false easting and the false northing of the projection. More...

virtual IlvMapsError	inverse (IlvCoordinate &coords) const
	Invserse-projects Cartesian coordinates to a latitude and a longitude. More...

IlBoolean	isBad () const
	Checks for an inconsistent state of the projection. More...

IlBoolean	isEllipsoidEnabled () const
	Indicates if non spherical ellipsoids can be used for the projection. More...

IlBoolean	isGeocentric () const
	Checks if the projection uses geocentric latitudes. More...

IlBoolean	isInverseEnabled () const
	Indicates if the inverse function is supported by the projection. More...

IlBoolean	isShared () const
	Indicates that the projection is shared. More...

IlBoolean	isUsingLongitudeReduction () const
	Returns `IlTrue` if the projection uses range reduction for longitudes. More...

void	lock ()
	Locks the projection.

virtual std::ostream &	printPROJ4Descriptor (std::ostream &ostr, IlvMapsError *status=0) const
	This virtual member function converts the projection to a string in the `PROJ4` format. More...

void	save (IlvOutputFile &outputFile) const
	Saves an instance of a subclass of `IlvProjection` to the specified output file. More...

void	setCentralMeridian (IlDouble lon)
	Sets the central meridian of the projection. More...

void	setCentralParallel (IlDouble lat)
	Sets the central parallel of the projection. More...

virtual IlvMapsError	setDatum (const IlvHorizontalDatum *datum)
	Sets the datum used for the projection. More...

void	setFalseEasting (IlDouble falseEasting)
	Sets the false easting of the projection. More...

void	setFalseNorthing (IlDouble falseNorthing)
	Sets the false northing of the projection. More...

void	setGeocentric (IlBoolean geoc)
	Specifies whether the projection uses geocentric or geodetic latitudes. More...

void	setShared ()
	Specifies that the projection will be shared. More...

void	setUnitConverter (const IlvUnitConverter &converter)
	Sets the unit converter of the projection. More...

void	setUsingLongitudeReduction (IlBoolean use)
	Specifies whether the projection uses longitude reduction. More...

void	unLock ()
	Unlocks the object. More...

Protected Member Functions
virtual IlvMapsError	eForward (IlvCoordinate &) const
	Must be redefined in subclasses to implement the projection for a non spherical ellipsoid. More...

virtual IlvMapsError	eInverse (IlvCoordinate &) const
	Implements the inverse projection for a non spherical ellipsoid. More...

virtual bool	isUsingProj4 () const
	Are we using proj4 implementation. More...

virtual IlvMapsError	sForward (IlvCoordinate &) const
	Must be redefined in subclasses to implement the projection for a sphere. More...

virtual IlvMapsError	sInverse (IlvCoordinate &) const
	Must be redefined in subclasses to implement the inverse projection for a sphere. More...

Protected Member Functions inherited from IlvProjection
	IlvProjection (IlBoolean ellipsoidEnabled, IlBoolean inverseEnabled, IlvProjectionGeometricProperty property)
	Initializes a new `IlvProjection` instance. More...

void	addError (IlvMapsError error)
	Used by the constructors of subclasses if an error occurs during an object initialization. More...

void	setError (IlvMapsError error)
	Sets the status of this projection. More...

Additional Inherited Members
Static Public Member Functions inherited from IlvProjection
static IlvProjectionClassInfo *	ClassInfo ()
	Returns the class information of the class. More...

static IlvClassInfo **	ClassInfoRef ()
	Returns the address of the class information of the class. More...

static IlvMapsError	InputError ()
	Indicates that the coordinates passed to the forward function are not in a valid range for radian angles.

static IlvMapsError	InvalidEllipsoidError ()
	Indicates that you attempt to set a non spherical ellipsoid to a projection that does not support non spherical ellipsoids.

static IlvProjection *	Load (IlvInputFile &inputFile)
	Loads a projection from the specified file. More...

static IlvProjection *	PROJ4ToIlvProjection (const char proj4Descriptor, IlvMapsError status=0)
	Creates the projection from a `PROJ4` descriptor. More...

static IlvMapsError	ToleranceConditionError ()
	Indicates that an internal projection computation failed. More...

static IlvMapsError	UnsupportedFeatureError ()
	Indicates that an unsupported projection feature is requested, like inverse projection for a projection that does not support inverse projection.

Detailed Description

Defines the Transverse Mercator projection.

Library: ilvmaps

This type of projection is generally used for large scale maps of predominantly north-south extension. The Transverse Mercator projection is the projection of a sphere on a cylinder that is tangent to a meridian. This projection is also known as:

Gauss Conformal
Gaus-Kruger
Transverse Cylindrical Orthomorphic

This class implements the forward and inverse functions and is available for spheres and ellipsoids.

The projection is Conformal.

Transverse Mercator Projection

See also: IlvMercatorProjection, IlvUniversalTransverseMercatorProjection.

Constructor & Destructor Documentation

◆ IlvTransverseMercatorProjection()

IlvTransverseMercatorProjection::IlvTransverseMercatorProjection ( IlDouble latitudeOfTrueScale = 0. )

This constructor initializes a new IlvTransverseMercatorProjection instance and sets the latitude of the true scale.

Parameters

latitudeOfTrueScale The latitude of the true scale.

Member Function Documentation

◆ eForward()

virtual IlvMapsError IlvTransverseMercatorProjection::eForward ( IlvCoordinate & ll ) const

protectedvirtual

Must be redefined in subclasses to implement the projection for a non spherical ellipsoid.

The default implementation returns IlvProjection::UnsupportedFeatureError().

Parameters

ll	Contains the longitude and latitude coordinates in radian (x = longitude, y = latitude).

Returns: An error code.

Reimplemented from IlvProjection.

◆ eInverse()

virtual IlvMapsError IlvTransverseMercatorProjection::eInverse ( IlvCoordinate & xy ) const

protectedvirtual

Implements the inverse projection for a non spherical ellipsoid.

The default implementation returns IlvProjection::UnsupportedFeatureError().

Parameters

xy	Contains the Cartesian coordinates to inverse.

Returns: An error code.

Reimplemented from IlvProjection.

◆ forward() [1/3]

virtual IlvMapsError IlvProjection::forward

Converts a latitude and a longitude to Cartesian coordinates (x, y).

The forward projection is computed either by the sForward() or by the eForward() method, depending on whether the ellipsoid is a sphere or not. The implementation of one of these methods depends on the projection. The result is then converted to the appropriate measurement unit.

This method returns IlvMaps::NoError() if the conversion is successful. Otherwise, it returns an error status.

Note: The variables llIn and xyOut can be identical. For example, you can write: projection.forward(coords, coords). If an error status is returned, the coordinates returned are not correct. Therefore, it is strongly recommended to pay attention to the error flag status.

Parameters

llIn	In Represents the longitude and latitude expressed in radian. The longitude must be in the range `[-PI; PI]` and the latitude must be in the range `[-PI/2; PI/2]`. If required, the function converts the latitude to a geocentric latitude. Then it centers the longitude and adjusts it.
xyOut	The resulting projected coordinates.

Returns: An IlvMapsError different from IlvMaps::NoError() if the conversion fails.

◆ forward() [2/3]

virtual IlvMapsError IlvTransverseMercatorProjection::forward	(	const IlvCoordinate &	llIn,
		IlvCoordinate &	xyOut
	)		const

virtual

Converts a latitude and a longitude to Cartesian coordinates (x, y).

The forward projection is computed either by the sForward() or by the eForward() method, depending on whether the ellipsoid is a sphere or not. The implementation of one of these methods depends on the projection. The result is then converted to the appropriate measurement unit.

This method returns IlvMaps::NoError() if the conversion is successful. Otherwise, it returns an error status.

Note: The variables llIn and xyOut can be identical. For example, you can write: projection.forward(coords, coords). If an error status is returned, the coordinates returned are not correct. Therefore, it is strongly recommended to pay attention to the error flag status.

Parameters

llIn	In Represents the longitude and latitude expressed in radian. The longitude must be in the range `[-PI; PI]` and the latitude must be in the range `[-PI/2; PI/2]`. If required, the function converts the latitude to a geocentric latitude. Then it centers the longitude and adjusts it.
xyOut	The resulting projected coordinates.

Returns: An IlvMapsError different from IlvMaps::NoError() if the conversion fails.

Reimplemented from IlvProjection.

◆ forward() [3/3]

virtual IlvMapsError IlvProjection::forward

Projects a latitude and a longitude pair to Cartesian coordinates.

This is equivalent to forward(coords, coords).

Parameters

coords The coordinates to be converted.

Returns: IlvMapsError different from IlvMaps::NoError() if the conversion fails.

See also: IlvProjection::forward().

◆ getScaleFactor()

IlDouble IlvTransverseMercatorProjection::getScaleFactor ( ) const

Returns the scale factor applied to the central meridian.

Returns: The scale factor applied to the central meridian.

◆ inverse() [1/3]

virtual IlvMapsError IlvProjection::inverse

Converts the specified coordinate to a latitude and a longitude.

This method converts the xyIn parameter, which represents Cartesian coordinates expressed in the measurement unit of the projection, to a latitude and a longitude.

This method returns IlvMaps::NoError() if the conversion is successful. Otherwise, it returns an error status.

Note: The variables llIn and xyOut can be identical. For example, you can write: projection.inverse(coords, coords).

Warning: If an error status is returned, the coordinates returned are not correct. Therefore, it is strongly recommended to pay attention to the error flag status.

Parameters

xyIn	The coordinates to be converted.
llOut	The converted coordinates.

Returns: An IlvMapsError different from IlvMaps::NoError() if the conversion fails.

◆ inverse() [2/3]

virtual IlvMapsError IlvTransverseMercatorProjection::inverse	(	const IlvCoordinate &	xyIn,
		IlvCoordinate &	llOut
	)		const

virtual

Converts the specified coordinate to a latitude and a longitude.

This method converts the xyIn parameter, which represents Cartesian coordinates expressed in the measurement unit of the projection, to a latitude and a longitude.

This method returns IlvMaps::NoError() if the conversion is successful. Otherwise, it returns an error status.

Note: The variables llIn and xyOut can be identical. For example, you can write: projection.inverse(coords, coords).

Warning: If an error status is returned, the coordinates returned are not correct. Therefore, it is strongly recommended to pay attention to the error flag status.

Parameters

xyIn	The coordinates to be converted.
llOut	The converted coordinates.

Returns: An IlvMapsError different from IlvMaps::NoError() if the conversion fails.

Reimplemented from IlvProjection.

◆ inverse() [3/3]

virtual IlvMapsError IlvProjection::inverse

Invserse-projects Cartesian coordinates to a latitude and a longitude.

This is equivalent to inverse(coords, coords).

Parameters

coords The coordinates to be converted before the call and the result after the call.

Returns: An IlvMapsError different from IlvMaps::NoError() if the conversion fails.

See also: IlvProjection::inverse().

◆ isUsingProj4()

virtual bool IlvTransverseMercatorProjection::isUsingProj4 ( ) const

protectedvirtual

Are we using proj4 implementation.

Returns: Returns true if we are using proj4 implementation, false otherwise

Reimplemented from IlvProjection.

◆ setEllipsoid()

virtual IlvMapsError IlvTransverseMercatorProjection::setEllipsoid ( const IlvEllipsoid & ellipsoid )

virtual

Sets the ellipsoid used for the projection.

This virtual member function sets the ellipsoid used for the projection. Most of the projections are initialized with a spherical ellipsoid with a radius of 6,370,997 meters.

This function returns IlvMaps::NoError() if the operation is successful or an error status if you specify a non spherical ellipsoid and your type does not support non spherical.

Parameters

ellipsoid The ellipsoid used for the projection.

Returns: IlvMapsError if the ellipsoid does not match the projection.

Reimplemented from IlvProjection.

◆ setLLCenter()

virtual void IlvTransverseMercatorProjection::setLLCenter	(	IlDouble	lon,
		IlDouble	lat
	)

virtual

Specifies the central meridian and the central parallel (in radian) associated with the projection.

By default, theses values are set to 0.

This function is virtual because it can be overridden by subclasses of IlvProjection to update the internal parameters when the center is changed.

Parameters

lon	The central meridian in radian.
lat	The central parallel in radian.

Reimplemented from IlvProjection.

Reimplemented in IlvUniversalTransverseMercatorProjection.

◆ setScaleFactor()

virtual void IlvTransverseMercatorProjection::setScaleFactor ( IlDouble k0 )

virtual

Sets the scale factor applied to the central meridian.

By default, the scale factor is 1.

Parameters

k0	The scale factor applied to the central meridian.

Reimplemented in IlvUniversalTransverseMercatorProjection.

◆ setXYOffset()

virtual void IlvTransverseMercatorProjection::setXYOffset	(	IlDouble	x0,
		IlDouble	y0
	)

virtual

Specifies the false easting and the false northing.

The default value is (0, 0). The false easting is an offset that is added to the x coordinate of the projected data, and the false northing is an offset that is added to the y coordinate of the projected data. Both offset should be expressed in meters.

Parameters

x0	The false easting.
y0	The false northing.

Reimplemented from IlvProjection.

◆ sForward()

virtual IlvMapsError IlvTransverseMercatorProjection::sForward ( IlvCoordinate & ll ) const

protectedvirtual

Must be redefined in subclasses to implement the projection for a sphere.

Parameters

ll	Contains the longitude and latitude coordinates in radian.

Returns: An error code.

Implements IlvProjection.

◆ sInverse()

virtual IlvMapsError IlvTransverseMercatorProjection::sInverse ( IlvCoordinate & xy ) const

protectedvirtual

Must be redefined in subclasses to implement the inverse projection for a sphere.

The default implementation returns IlvProjection::UnsupportedFeatureError().

Parameters

xy	Contains the Cartesian coordinates to inverse.

Returns: An error code.

Reimplemented from IlvProjection.

◆ write()

virtual void IlvTransverseMercatorProjection::write ( IlvOutputFile & outputFile ) const

virtual

Saves the parameters of a projection to the specified output file.

It must be overridden by subclasses of IlvProjection that need to save additional parameters.

This function should not be directly called; use the save() function instead.

Parameters

outputFile The file to write the projection parameters to.

Reimplemented from IlvProjection.

Reimplemented in IlvUniversalTransverseMercatorProjection.

Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ IlvTransverseMercatorProjection()

Member Function Documentation

◆ eForward()

◆ eInverse()

◆ forward() [1/3]

◆ forward() [2/3]

◆ forward() [3/3]

◆ getScaleFactor()

◆ inverse() [1/3]

◆ inverse() [2/3]

◆ inverse() [3/3]

◆ isUsingProj4()

◆ setEllipsoid()

◆ setLLCenter()

◆ setScaleFactor()

◆ setXYOffset()

◆ sForward()

◆ sInverse()

◆ write()