IlvConicProjection Class Reference

This abstract class is the base class for all the conic projections in the library. More...

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

Inheritance diagram for IlvConicProjection:

Public Member Functions
virtual IlvProjectionClassInfo *	getClassInfo () const
	Returns the class information for the projection. More...
IlDouble	getSecantLatitude1 (void) const
	Gets the first secant latitude. More...
IlDouble	getSecantLatitude2 (void) const
	Gets the second secant latitude. More...
const IlvCoordinate &	getSecantLatitudes () const
	Returns the secant latitudes of the projection in an IlvCoordinate. More...
IlvMapsError	setSecantLatitude1 (IlDouble v)
	Sets the first secant latitude. More...
IlvMapsError	setSecantLatitude2 (IlDouble v)
	Sets the second secant latitude. More...
virtual IlvMapsError	setSecantLatitudes (const IlvCoordinate &secant)
	Sets the latitudes at which the cone of the projection intersects with the earth. 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...
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 &, 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...
virtual IlvMapsError	setEllipsoid (const IlvEllipsoid &ellipsoid)
	Sets the ellipsoid 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...
virtual void	setLLCenter (IlDouble lon, IlDouble lat)
	Specifies the central meridian and the central parallel (in radian) associated with the projection. 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
	IlvConicProjection (IlBoolean ellipsoidEnabled, IlBoolean inverseEnabled, IlvProjectionGeometricProperty property, IlStringHashTable *proj4Params=0)
	Initializes a new instance of the class IlvConicProjection. 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...
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...
void	setError (IlvMapsError error)
	Sets the status of this projection. More...
virtual IlvMapsError	sForward (IlvCoordinate &ll) const =0
	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...

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 abstract class is the base class for all the conic projections in the library.

A conic projection transfers the image of the globe to a cone, either secant or tangent to the surface of the earth. The latitudes at which the cone intersects with the globe can be specified with the function setSecantLatitudes(IlvCoordinate secant). The secant parameter is a vector that contains two values:

• secant.x represents the first latitude at which the cone intersects with the earth.

• secant.y represents the second latitude.
  When the cone is tangent to the earth, secant.x equals secant.y.

Warning

[note] The cylindrical (secant.x = - secant.y) or azimuthal (secant.x = secant.y = 90 degrees) limiting forms of a conic projection should not be used. Library: ilvmaps

Constructor & Destructor Documentation

IlvConicProjection::IlvConicProjection ( IlBoolean  ellipsoidEnabled, IlBoolean  inverseEnabled, IlvProjectionGeometricProperty  property, IlStringHashTable *  proj4Params = 0  )

protected

Initializes a new instance of the class IlvConicProjection.

Parameters

ellipsoidEnabled	A 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	A Boolean argument that should be set to IlTrue if the projection implements an inverse function. This type of projection should implement the sInverse and eInverse member functions if ellipsoids are supported.
property	Specifies the geometric property of the projection. This argument can take one of the following values: IlvNoneProjectionGeometricProperty IlvConformalProjectionGeometricProperty IlvEqualAreaProjectionGeometricProperty

Member Function Documentation

virtual IlvProjectionClassInfo* IlvConicProjection::getClassInfo ( ) const

virtual

Returns the class information for the projection.

Returns

The class information for the projection.

Reimplemented from IlvProjection.

Reimplemented in IlvFrenchLambertProjection.

IlDouble IlvConicProjection::getSecantLatitude1

(

void

)

const

Gets the first secant latitude.

Returns

The first secant latitude.

See Also

IlvConicProjection::getSecantLatitudes.

IlDouble IlvConicProjection::getSecantLatitude2

(

void

)

const

Gets the second secant latitude.

Returns

The second secant latitude.

See Also

IlvConicProjection::getSecantLatitudes.

const IlvCoordinate& IlvConicProjection::getSecantLatitudes

(

)

const

Returns the secant latitudes of the projection in an IlvCoordinate.

Returns

The IlvCoordinate object containing the secant latitudes.

IlvMapsError IlvConicProjection::setSecantLatitude1

(

IlDouble

v

)

Sets the first secant latitude.

Parameters

v	The first secant latitude.

Returns

An error status if the latitudes specify a limiting form.

See Also

IlvConicProjection::setSecantLatitudes.

IlvMapsError IlvConicProjection::setSecantLatitude2

(

IlDouble

v

)

Sets the second secant latitude.

Parameters

v	The second secant latitude.

Returns

An error status if the latitudes specify a limiting form.

See Also

IlvConicProjection::setSecantLatitudes.

virtual IlvMapsError IlvConicProjection::setSecantLatitudes ( const IlvCoordinate &  secant )

virtual

Sets the latitudes at which the cone of the projection intersects with the earth.

Parameters

secant

A vector that contains two values: secant.x represents the first latitude at which the cone intersects with the earth. secant.y represents the second latitude at which the cone intersects with the earth. Both values are expressed in radian.

Returns

An error status if the latitudes specify a limiting form, that is, if secant.x = -secant.y or secant.x = secant.y = PI/2.

Reimplemented in IlvFrenchLambertProjection, IlvLambertEqualAreaConicProjection, IlvAlbersEqualAreaProjection, and IlvLambertConformalConicProjection.

virtual void IlvConicProjection::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 IlvFrenchLambertProjection, IlvLambertEqualAreaConicProjection, IlvLambertConformalConicProjection, and IlvAlbersEqualAreaProjection.