IlvProjection Class Reference

All projections in the library inherit from this abstract class. More...

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

Inheritance diagram for IlvProjection:

List of all members.

Public Member Functions
virtual IlvProjection *	copy () const =0
	Returns a copy of the projection. It must be overridden in each subclass.
IlvMapsError	forward (IlvCoordinate &x) const
	This member function converts a latitude and a longitude to Cartesian coordinates.
IlvMapsError	forward (const IlvCoordinate &llIn, IlvCoordinate &xyOut) const
	Converts a latitude and a longitude to Cartesian coordinates (x,y).
IlDouble	getCentralMeridian () const
	Returns the central meridian of the projection.
IlDouble	getCentralParallel () const
	Returns the central parallel of the projection.
virtual IlvProjectionClassInfo *	getClassInfo () const
	Returns the class information for the projection.
const IlvHorizontalDatum *	getDatum (void) const
	Returns the horizontal datum used for the projection.
const IlvEllipsoid *	getEllipsoid (void) const
	Returns the ellipsoid used for the projection.
IlvMapsError	getError () const
	Returns the status of the projection. If the projection is valid, the function returns IlvMapsError::NoError(), otherwise, it returns an error code. See the IlvMaps class to know how to interpret the error codes.
IlDouble	getFalseEasting () const
	Returns the false easting of the projection.
IlDouble	getFalseNorthing () const
	Returns the false northing of the projection.
IlvProjectionInterface *	getInterface ()
	Returns the interface of the projection.
IlvCoordinate	getLLCenter (void) const
	Returns the central meridian and the central parallel associated with the projection (0-0 by default).
IlvProjectionGeometricProperty	getProperty () const
	Returns the geometric property of the projection.
const IlvUnitConverter *	getUnitConverter () const
	Returns the unit converter.
IlvCoordinate	getXYOffset (void) const
	Returns the false easting and the false northing of the projection.
IlvMapsError	inverse (IlvCoordinate &x) const
	Converts the IlvCoordinate representing Cartesian coordinates to a latitude and a longitude.
IlvMapsError	inverse (const IlvCoordinate &xyIn, IlvCoordinate &llOut) const
	Converts the specified coordinate to a latitude and a longitude.
IlBoolean	isBad () const
	Checks for an inconsistent state of the projection.
IlBoolean	isEllipsoidEnabled () const
	Returns IlTrue if non spherical ellipsoids can be used for the projection.
IlBoolean	isGeocentric () const
	Checks if the projection uses geocentric latitudes.
IlBoolean	isInverseEnabled () const
	Returns IlTrue if the inverse function is supported by the projection.
IlBoolean	isShared () const
	Returns IlTrue if the projection is shared.
IlBoolean	isUsingLongitudeReduction () const
	Returns IlTrue if the projection uses range reduction for longitudes.
void	lock ()
	Locks the projection.
virtual IL_STDPREF ostream &	printPROJ4Descriptor (IL_STDPREF ostream &, IlvMapsError *status=0) const
	This virtual member function converts the projection to a string in the PROJ4 format.
void	save (IlvOutputFile &outputFile) const
	Saves an instance of a subclass of IlvProjection to the specified output file.
void	setCentralMeridian (IlDouble lon)
	Sets the central meridian of the projection.
void	setCentralParallel (IlDouble lat)
	Sets the central parallel of the projection.
virtual IlvMapsError	setDatum (const IlvHorizontalDatum *datum)
	Sets the datum used for the projection.
virtual IlvMapsError	setEllipsoid (const IlvEllipsoid &ellipsoid)
	Sets the ellipsoid used for the projection.
void	setFalseEasting (IlDouble falseEasting)
	Sets the false easting of the projection.
void	setFalseNorthing (IlDouble falseNorthing)
	Sets the false northing of the projection.
void	setGeocentric (IlBoolean geoc)
	Specifies whether the projection uses geocentric or geodetic latitudes.
virtual void	setLLCenter (IlDouble lon, IlDouble lat)
	Specifies the central meridian and the central parallel (in radian) associated with the projection.
void	setShared ()
	Specifies that the projection will be shared.
void	setUnitConverter (const IlvUnitConverter &converter)
	Sets the unit converter of the projection. The default unit is meters.
void	setUsingLongitudeReduction (IlBoolean use)
	Specifies whether the projection uses longitude reduction.
void	setXYOffset (IlDouble x0, IlDouble y0)
	Specifies the false easting and the false northing.
void	unLock ()
	Unlocks the object.
virtual void	write (IlvOutputFile &outputFile) const
	Saves the parameters of a projection to the specified output file.
Static Public Member Functions
static IlvProjectionClassInfo *	ClassInfo ()
	Returns the class information of the class.
static IlvClassInfo **	ClassInfoRef ()
	Returns the address of the class information of the class.
static IlvMapsError	InputError ()
	Returned if the coordinates passed to the forward function are not in a valid range for radian angles.
static IlvMapsError	InvalidEllipsoidError ()
	Returned if 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.
static IlvProjection *	PROJ4ToIlvProjection (const char *PROJ4descriptor, IlvMapsError *status=0)
	Creates the projection specified by proj4Descriptor.
static IlvMapsError	ToleranceConditionError ()
	Returned when an internal projection computation fails. Some projections, however, can return more specific error codes in this case.
static IlvMapsError	UnsupportedFeatureError ()
	Returned if an unsupported projection feature is requested, like inverse projection for a projection that does not support inverse projection.
Protected Member Functions
	IlvProjection (IlBoolean ellipsoidEnabled, IlBoolean inverseEnabled, IlvProjectionGeometricProperty property)
	This constructor initializes a new instance of the class.
void	addError (IlvMapsError error)
	Used by the constructors of subclasses if an error occurs during an object initialization.
virtual IlvMapsError	eForward (IlvCoordinate &ll) const
	Must be redefined in subclasses to implement the projection for a non spherical ellipsoid.
virtual IlvMapsError	eInverse (IlvCoordinate &xy) const
	Implements the inverse projection for a non spherical ellipsoid.
void	setError (IlvMapsError error)
	Sets the status of this projection.
virtual IlvMapsError	sForward (IlvCoordinate &ll) const =0
	Must be redefined in subclasses to implement the projection for a sphere.
virtual IlvMapsError	sInverse (IlvCoordinate &xy) const
	Must be redefined in subclasses to implement the inverse projection for a sphere.

---

Detailed Description

All projections in the library inherit from this abstract class.

See also:

IlvCoordinate, IlvMaps, IlvProjectionClassInfo, IlvProjectionDictionary, IlvProjectionGeometricProperty, IlvProjectionInterface, IlvUnitConverter. Library: ilvmaps

---

Constructor & Destructor Documentation

IlvProjection::IlvProjection	(	IlBoolean	ellipsoidEnabled,
		IlBoolean	inverseEnabled,
		IlvProjectionGeometricProperty	property
	)			[protected]

This constructor initializes a new instance of the class.

Parameters:

	ellipsoidEnabled	Boolean argument that should be set to IlTrue if non spherical ellipsoids can be used for the projection. Projections supporting non spherical ellipsoids should implement the eForward member function.
	inverseEnabled	Boolean argument that should be set to IlTrue if the projection implements an inverse function. This type of projections should implement the sInverse and eInverse member functions if ellipsoids are supported.
	property	Specifies the geometric property of the projection.

See also:

IlvProjectionGeometricProperty

---

Member Function Documentation

void IlvProjection::addError

(

IlvMapsError

error

)

[protected]

Used by the constructors of subclasses if an error occurs during an object initialization.

This protected method is used by subclasses of IlvProjection to set the error status of the projection within the constructors and the parameterizing functions if the parameters received are inconsistent. If the projection status is already different from IlvMaps::NoError(), this function does nothing.

Parameters:

error

The error.

static IlvProjectionClassInfo* IlvProjection::ClassInfo

(

)

[static]

Returns the class information of the class.

This static function is also available for the subclasses of IlvProjection.

Returns:

The IlvProjectionClassInfo of the class.

Reimplemented in IlvAlbersEqualAreaProjection, IlvAzimuthalEquidistantProjection, IlvCassiniProjection, IlvConicProjection, IlvCylindricalEqualAreaProjection, IlvEquidistantCylindricalProjection, IlvFrenchLambertProjection, IlvGeographicProjection, IlvGnomonicProjection, IlvLambertAzimuthalEqualAreaProjection, IlvLambertEqualAreaConicProjection, IlvLambertConformalConicProjection, IlvMercatorProjection, IlvMillerCylindricalProjection, IlvOrthographicProjection, IlvPolyconicProjection, IlvStereographicProjection, IlvTransverseMercatorProjection, IlvUniversalPolarStereographicProjection, IlvUniversalTransverseMercatorProjection, and IlvUnknownProjection.

static IlvClassInfo** IlvProjection::ClassInfoRef

(

)

[static]

Returns the address of the class information of the class.

This static function is also available for the subclasses of IlvProjection.

Returns:

The address of the IlvProjectionClassInfo of the class.

Reimplemented in IlvAlbersEqualAreaProjection, IlvAzimuthalEquidistantProjection, IlvCassiniProjection, IlvConicProjection, IlvCylindricalEqualAreaProjection, IlvEquidistantCylindricalProjection, IlvFrenchLambertProjection, IlvGeographicProjection, IlvGnomonicProjection, IlvLambertAzimuthalEqualAreaProjection, IlvLambertEqualAreaConicProjection, IlvLambertConformalConicProjection, IlvMercatorProjection, IlvMillerCylindricalProjection, IlvOrthographicProjection, IlvPolyconicProjection, IlvStereographicProjection, IlvTransverseMercatorProjection, IlvUniversalPolarStereographicProjection, IlvUniversalTransverseMercatorProjection, and IlvUnknownProjection.

virtual IlvProjection* IlvProjection::copy

(

)

const [pure virtual]

Returns a copy of the projection. It must be overridden in each subclass.

Returns:

The copy of the object.

Implemented in IlvAlbersEqualAreaProjection, IlvAzimuthalEquidistantProjection, IlvCassiniProjection, IlvCylindricalEqualAreaProjection, IlvEquidistantCylindricalProjection, IlvFrenchLambertProjection, IlvGeographicProjection, IlvGnomonicProjection, IlvLambertAzimuthalEqualAreaProjection, IlvLambertEqualAreaConicProjection, IlvLambertConformalConicProjection, IlvMercatorProjection, IlvMillerCylindricalProjection, IlvOrthographicProjection, IlvPolyconicProjection, IlvStereographicProjection, IlvTransverseMercatorProjection, IlvUniversalPolarStereographicProjection, IlvUniversalTransverseMercatorProjection, and IlvUnknownProjection.

virtual IlvMapsError IlvProjection::eForward

(

IlvCoordinate &

ll

)

const [protected, virtual]

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 in IlvAlbersEqualAreaProjection, IlvAzimuthalEquidistantProjection, IlvCassiniProjection, IlvCylindricalEqualAreaProjection, IlvLambertAzimuthalEqualAreaProjection, IlvLambertConformalConicProjection, IlvMercatorProjection, IlvPolyconicProjection, IlvStereographicProjection, IlvTransverseMercatorProjection, and IlvUnknownProjection.

virtual IlvMapsError IlvProjection::eInverse

(

IlvCoordinate &

xy

)

const [protected, virtual]

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 in IlvAlbersEqualAreaProjection, IlvAzimuthalEquidistantProjection, IlvCassiniProjection, IlvCylindricalEqualAreaProjection, IlvLambertAzimuthalEqualAreaProjection, IlvLambertConformalConicProjection, IlvMercatorProjection, IlvPolyconicProjection, IlvStereographicProjection, IlvTransverseMercatorProjection, and IlvUnknownProjection.

IlvMapsError IlvProjection::forward

(

IlvCoordinate &

x

)

const

This member function converts a latitude and a longitude to Cartesian coordinates.

Parameters:

x

IlvCoordinate containing the coordinates to be converted.

Returns:

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

See also:

IlvProjection::forward

IlvMapsError IlvProjection::forward	(	const IlvCoordinate &	llIn,
		IlvCoordinate &	xyOut
	)			const

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.

Warning:

[note] The variables llIn and xyOut can be identical. For example, you can write: projection.forward(coord,coord). 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	Represents the longitude and latitude expressed in radian (x = longitude, y = latitude). 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 data.

Returns:

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

IlDouble IlvProjection::getCentralMeridian

(

)

const

Returns the central meridian of the projection.

Returns:

The central meridian of the projection.

See also:

IlvProjection::getLLCenter

IlDouble IlvProjection::getCentralParallel

(

)

const

Returns the central parallel of the projection.

Returns:

The central parallel of the projection.

See also:

IlvProjection::getLLCenter

virtual IlvProjectionClassInfo* IlvProjection::getClassInfo

(

)

const [virtual]

Returns the class information for the projection.

Returns:

The class information for the projection.

Reimplemented in IlvAlbersEqualAreaProjection, IlvAzimuthalEquidistantProjection, IlvCassiniProjection, IlvConicProjection, IlvCylindricalEqualAreaProjection, IlvEquidistantCylindricalProjection, IlvFrenchLambertProjection, IlvGeographicProjection, IlvGnomonicProjection, IlvLambertAzimuthalEqualAreaProjection, IlvLambertEqualAreaConicProjection, IlvLambertConformalConicProjection, IlvMercatorProjection, IlvMillerCylindricalProjection, IlvOrthographicProjection, IlvPolyconicProjection, IlvStereographicProjection, IlvTransverseMercatorProjection, IlvUniversalPolarStereographicProjection, IlvUniversalTransverseMercatorProjection, and IlvUnknownProjection.

const IlvHorizontalDatum* IlvProjection::getDatum

(

void

)

const

Returns the horizontal datum used for the projection.

Warning:

The datum returned is destroyed when the projection itself is destroyed. You can however make a copy of the ellipsoid using the IlvHorizontalDatum::copy() method if you want to reuse this datum after the projection has been destroyed.

const IlvEllipsoid* IlvProjection::getEllipsoid

(

void

)

const

Returns the ellipsoid used for the projection.

Warning:

The ellipsoid returned is destroyed when the projection itself is destroyed. You can however make a copy of the ellipsoid using the IlvEllipsoid::copy() method if you want to reuse this ellipsoid after the projection has been destroyed.

Returns:

The ellipsoid used for the projection.

IlvMapsError IlvProjection::getError

(

)

const

Returns the status of the projection. If the projection is valid, the function returns IlvMapsError::NoError(), otherwise, it returns an error code. See the IlvMaps class to know how to interpret the error codes.

Returns:

The status of the projection.

IlDouble IlvProjection::getFalseEasting

(

)

const

Returns the false easting of the projection.

Returns:

The false easting of the projection.

See also:

IlvProjection::getXYOffset

IlDouble IlvProjection::getFalseNorthing

(

)

const

Returns the false northing of the projection.

Returns:

The false northing of the projection.

See also:

IlvProjection::getXYOffset

IlvProjectionInterface* IlvProjection::getInterface

(

)

Returns the interface of the projection.

A projection interface gives run-time information about the parameters of a projection, and makes it possible to modify these parameters. It is generally used to build dynamic projection editors.

Returns:

The interface of the projection.

IlvCoordinate IlvProjection::getLLCenter

(

void

)

const

Returns the central meridian and the central parallel associated with the projection (0-0 by default).

In the IlvCoordinate object returned, x is the central meridian while y is the central parallel of the projection. These values are expressed in radian.

Returns:

The central meridian and the central parallel associated with the projection.

IlvProjectionGeometricProperty IlvProjection::getProperty

(

)

const

Returns the geometric property of the projection.

Returns:

The geometric property of the projection.

See also:

IlvProjectionGeometricProperty

const IlvUnitConverter* IlvProjection::getUnitConverter

(

)

const

Returns the unit converter.

Warning:

The converter returned is destroyed when the projection itself is destroyed. You can however make a copy of the converter using the method IlvUnitConverter::copy() if you want to reuse this unit converter after the projection has been destroyed

Returns:

The unit converter.

IlvCoordinate IlvProjection::getXYOffset

(

void

)

const

Returns the false easting and the false northing of the projection.

Returns:

IlvCoordinate containing the false easting and the false northing of the projection.

IlvMapsError IlvProjection::inverse

(

IlvCoordinate &

x

)

const

Converts the IlvCoordinate representing Cartesian coordinates to a latitude and a longitude.

Parameters:

x

Holding the coordinate to be converted before the call and the result after the call.

Returns:

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

See also:

IlvProjection::inverse

IlvMapsError IlvProjection::inverse	(	const IlvCoordinate &	xyIn,
		IlvCoordinate &	llOut
	)			const

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.

Warning:

[note] The variables llIn and xyOut can be identical. For example, you can write: projection.inverse(coord,coord).

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.

IlBoolean IlvProjection::isBad

(

)

const

Checks for an inconsistent state of the projection.

Returns IlTrue if the projection is in an inconsistent state because wrong parameters have been passed to the constructor.

IlBoolean IlvProjection::isEllipsoidEnabled

(

)

const

Returns IlTrue if non spherical ellipsoids can be used for the projection.

Returns:

IlTrue if non spherical ellipsoids can be used for the projection.

IlBoolean IlvProjection::isGeocentric

(

)

const

Checks if the projection uses geocentric latitudes.

Returns:

IlTrue if the projection uses geocentric latitudes.

IlBoolean IlvProjection::isInverseEnabled

(

)

const

Returns IlTrue if the inverse function is supported by the projection.

Returns:

IlTrue if the inverse function is supported by the projection, IlFalse otherwise.

IlBoolean IlvProjection::isShared

(

)

const

Returns IlTrue if the projection is shared.

Warning:

If a projection is shared, the projection should not be deleted directly.

Returns:

IlTrue if the projection is shared, IlFalse otherwise.

See also:

lock, unLock.

IlBoolean IlvProjection::isUsingLongitudeReduction

(

)

const

Returns IlTrue if the projection uses range reduction for longitudes.

Returns:

IlTrue if the projection uses range reduction for longitudes, IlFalse otherwise.

static IlvProjection* IlvProjection::Load

(

IlvInputFile &

inputFile

)

[static]

Loads a projection from the specified file.

It can be used, for example, within the read method of a subclass of IlvNamedProperty. If the load operation fails, the function returns a null pointer, otherwise, it returns a pointer to the projection which was read. If the file contained invalid parameters, however, the returned projection can have an error status (see the member function IlvProjection::getError).
The returned projection must be deleted by the user.

Parameters:

inputFile

The file to read the projection from.

Returns:

The read IlvProjection or a null pointer if the load operation fails.

virtual IL_STDPREF ostream& IlvProjection::printPROJ4Descriptor	(	IL_STDPREF ostream &	,
		IlvMapsError *	status = 0
	)			const [virtual]

This virtual member function converts the projection to a string in the PROJ4 format.

Parameters:

	ostream	The output stream receiving the string.
	status	IlvMapsError reporting a write error.

Returns:

The output stream.

Reimplemented in IlvGeographicProjection.

static IlvProjection* IlvProjection::PROJ4ToIlvProjection	(	const char *	PROJ4descriptor,
		IlvMapsError *	status = 0
	)			[static]

Creates the projection specified by proj4Descriptor.

It returns a null pointer if an error occurs, that is, if proj4Descriptor specifies an unregistered projection or contains syntax errors. If passed, the status optional argument returns the status of the operation, namely:

• IlvMap::NoError() if no read problem occurred, or
• the corresponding error code otherwise (see the class IlvMaps to know how to interpret the error codes returned).

Parameters:

	PROJ4descriptor	The PROJ4 description.
	status	IlvMapsError indicating an invalid string or an unregistered projection.

void IlvProjection::save

(

IlvOutputFile &

outputFile

)

const

Saves an instance of a subclass of IlvProjection to the specified output file.

It can be used, for example, within the write method of a subclass of IlvNamedProperty.

Parameters:

outputFile

The file to write the projection to.

void IlvProjection::setCentralMeridian

(

IlDouble

lon

)

Sets the central meridian of the projection.

Parameters:

lon

The central meridian in radian.

See also:

IlvProjection::setLLCenter

void IlvProjection::setCentralParallel

(

IlDouble

lat

)

Sets the central parallel of the projection.

Parameters:

lat

The central parallel in radian.

See also:

IlvProjection::setLLCenter

virtual IlvMapsError IlvProjection::setDatum

(

const IlvHorizontalDatum *

datum

)

[virtual]

Sets the datum used for the projection.

This method sets the datum used for the projection. The specified datum is copied by this projection.

Returns:

The datum or a null pointer if not defined.

virtual IlvMapsError IlvProjection::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 in IlvAlbersEqualAreaProjection, IlvAzimuthalEquidistantProjection, IlvCassiniProjection, IlvCylindricalEqualAreaProjection, IlvGeographicProjection, IlvLambertAzimuthalEqualAreaProjection, IlvLambertConformalConicProjection, IlvMercatorProjection, IlvPolyconicProjection, IlvStereographicProjection, and IlvTransverseMercatorProjection.

void IlvProjection::setError

(

IlvMapsError

error

)

[protected]

Sets the status of this projection.

Subclasses of IlvProjection should call this method to set the status of the projection. The new error status error replaces the current status of this projection.

Parameters:

error

The new error status.

See also:

IlvProjection::getError

void IlvProjection::setFalseEasting

(

IlDouble

falseEasting

)

Sets the false easting of the projection.

Parameters:

falseEasting

The false easting of the projection.

See also:

IlvProjection::setXYOffset

void IlvProjection::setFalseNorthing

(

IlDouble

falseNorthing

)

Sets the false northing of the projection.

Parameters:

falseNorthing

The false northing of the projection.

See also:

IlvProjection::setFalseNorthing

void IlvProjection::setGeocentric

(

IlBoolean

geoc

)

Specifies whether the projection uses geocentric or geodetic latitudes.

The IlvProjection constructor sets this parameter to IlFalse.

Parameters:

geoc

If IlTrue, the projection uses geocentric latitudes.

virtual void IlvProjection::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 in IlvAlbersEqualAreaProjection, IlvAzimuthalEquidistantProjection, IlvCassiniProjection, IlvFrenchLambertProjection, IlvGnomonicProjection, IlvLambertAzimuthalEqualAreaProjection, IlvLambertConformalConicProjection, IlvOrthographicProjection, IlvPolyconicProjection, IlvStereographicProjection, IlvUniversalPolarStereographicProjection, and IlvUniversalTransverseMercatorProjection.

void IlvProjection::setShared

(

)

Specifies that the projection will be shared.

Warning:

If a projection is shared, the projection should not be deleted directly.

See also:

lock, unLock.

void IlvProjection::setUnitConverter

(

const IlvUnitConverter &

converter

)

Sets the unit converter of the projection. The default unit is meters.

Parameters:

converter

The unit converter.

void IlvProjection::setUsingLongitudeReduction

(

IlBoolean

use

)

Specifies whether the projection uses longitude reduction.

The normal geographic range for longitude is between 180E and 180W. By default, the Boolean flag is set to IlTrue, which means that the internal range of longitude is reduced to this range. Setting it to IlFalse disables internal range reduction. However, this should be used with care in applications.

void IlvProjection::setXYOffset	(	IlDouble	x0,
		IlDouble	y0
	)

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.

virtual IlvMapsError IlvProjection::sForward

(

IlvCoordinate &

ll

)

const [protected, pure virtual]

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

Parameters:

ll

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

Implemented in IlvAlbersEqualAreaProjection, IlvAzimuthalEquidistantProjection, IlvCassiniProjection, IlvCylindricalEqualAreaProjection, IlvEquidistantCylindricalProjection, IlvGeographicProjection, IlvGnomonicProjection, IlvLambertAzimuthalEqualAreaProjection, IlvLambertConformalConicProjection, IlvMercatorProjection, IlvMillerCylindricalProjection, IlvOrthographicProjection, IlvPolyconicProjection, IlvStereographicProjection, IlvTransverseMercatorProjection, and IlvUnknownProjection.

virtual IlvMapsError IlvProjection::sInverse

(

IlvCoordinate &

xy

)

const [protected, virtual]

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 in IlvAlbersEqualAreaProjection, IlvAzimuthalEquidistantProjection, IlvCassiniProjection, IlvCylindricalEqualAreaProjection, IlvEquidistantCylindricalProjection, IlvGeographicProjection, IlvGnomonicProjection, IlvLambertAzimuthalEqualAreaProjection, IlvLambertConformalConicProjection, IlvMercatorProjection, IlvMillerCylindricalProjection, IlvOrthographicProjection, IlvPolyconicProjection, IlvStereographicProjection, IlvTransverseMercatorProjection, and IlvUnknownProjection.

void IlvProjection::unLock

(

)

Unlocks the object.

If the projection does not have any lock, it is deleted.

virtual void IlvProjection::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 in IlvAlbersEqualAreaProjection, IlvAzimuthalEquidistantProjection, IlvConicProjection, IlvCylindricalEqualAreaProjection, IlvEquidistantCylindricalProjection, IlvFrenchLambertProjection, IlvLambertEqualAreaConicProjection, IlvLambertConformalConicProjection, IlvMercatorProjection, IlvPolyconicProjection, IlvStereographicProjection, IlvTransverseMercatorProjection, IlvUniversalPolarStereographicProjection, and IlvUniversalTransverseMercatorProjection.