This class defines the Polyconic projection. More...

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

Inheritance diagram for IlvPolyconicProjection:

Public Member Functions
	IlvPolyconicProjection ()
	Constructor. More...

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

virtual void	setLLCenter (IlDouble lon, IlDouble lat)
	Specifies the central meridian and the central parallel (in radian) associated with the projection. 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. It must be overridden in each subclass. More...

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

IlvMapsError	forward (IlvCoordinate &x) const
	This member function converts a latitude and a longitude 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 (void) const
	Returns the ellipsoid used for the projection. More...

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

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

IlvMapsError	inverse (IlvCoordinate &x) const
	Converts the `IlvCoordinate` representing Cartesian coordinates to a latitude and a longitude. More...

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

IlBoolean	isEllipsoidEnabled () const
	Returns `IlTrue` 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
	Returns `IlTrue` if the inverse function is supported by the projection. More...

IlBoolean	isShared () const
	Returns `IlTrue` if 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 IL_STDPREF ostream &	printPROJ4Descriptor (IL_STDPREF 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. The default unit is meters. More...

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

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

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

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

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

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

virtual IlvMapsError	sInverse (IlvCoordinate &xy) 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)
	This constructor initializes a new instance of the class. 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 ()
	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. More...

static IlvProjection *	PROJ4ToIlvProjection (const char PROJ4descriptor, IlvMapsError status=0)
	Creates the projection specified by proj4Descriptor. More...

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.

Detailed Description

This class defines the Polyconic projection.

The polyconic projection offers a good compromise between shape distortion and area distortion. This projection was selected in 1819 by the first U.S. survey organization for large-scale mapping in the United States. This projection was used until the mid-1950s for standard topographic maps of the United States.

This projection applies to both spherical and non-spherical ellipsoids and implements an inverse function. However, it is impossible to inverse Cartesian coordinates representing a longitude further than 75 degrees from the center of the projection.

This projection is neither conformal nor equal area.

Polyconic Projection

Library: ilvmaps

Constructor & Destructor Documentation

IlvPolyconicProjection::IlvPolyconicProjection ( )

Constructor.

Initialize a new instance of the class IlvPolyconicProjection.

Member Function Documentation

virtual IlvMapsError IlvPolyconicProjection::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.

virtual IlvMapsError IlvPolyconicProjection::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.

virtual IlvMapsError IlvPolyconicProjection::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.

virtual void IlvPolyconicProjection::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.

virtual IlvMapsError IlvPolyconicProjection::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 (x = longitude, y = latitude).

Implements IlvProjection.

virtual IlvMapsError IlvPolyconicProjection::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.

virtual void IlvPolyconicProjection::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.

Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation