Class for doing transforms between two map coordinate systems. More...

#include <qgscoordinatetransform.h>

Public Types
enum	TransformDirection { ForwardTransform , ReverseTransform }
	Enum used to indicate the direction (forward or inverse) of the transform. More...

Public Member Functions
	QgsCoordinateTransform ()
	Default constructor, creates an invalid QgsCoordinateTransform. More...

	QgsCoordinateTransform (const QgsCoordinateReferenceSystem &source, const QgsCoordinateReferenceSystem &destination, const QgsCoordinateTransformContext &context)
	Constructs a QgsCoordinateTransform to transform from the source to destination coordinate reference system. More...

	QgsCoordinateTransform (const QgsCoordinateReferenceSystem &source, const QgsCoordinateReferenceSystem &destination, const QgsProject *project)
	Constructs a QgsCoordinateTransform to transform from the source to destination coordinate reference system, when used with the given project. More...

	QgsCoordinateTransform (const QgsCoordinateReferenceSystem &source, const QgsCoordinateReferenceSystem &destination, int sourceDatumTransformId, int destinationDatumTransformId)
	Constructs a QgsCoordinateTransform to transform from the source to destination coordinate reference system, with the specified datum transforms (see QgsDatumTransform). More...

	QgsCoordinateTransform (const QgsCoordinateTransform &o)
	Copy constructor. More...

	~QgsCoordinateTransform ()

bool	allowFallbackTransforms () const
	Returns whether "ballpark" fallback transformations will be used in the case that the specified coordinate operation fails (such as when coordinates from outside a required grid shift file are transformed). More...

QgsCoordinateTransformContext	context () const
	Returns the context in which the coordinate transform will be calculated. More...

QString	coordinateOperation () const
	Returns a Proj string representing the coordinate operation which will be used to transform coordinates. More...

QgsCoordinateReferenceSystem	destinationCrs () const
	Returns the destination coordinate reference system, which the transform will transform coordinates to. More...

Q_DECL_DEPRECATED int	destinationDatumTransformId () const
	Returns the ID of the datum transform to use when projecting to the destination CRS. More...

void	disableFallbackOperationHandler (bool disabled)
	Sets whether the default fallback operation handler is disabled for this transform instance. More...

bool	fallbackOperationOccurred () const
	Returns `true` if a fallback operation occurred for the most recent transform. More...

QgsDatumTransform::TransformDetails	instantiatedCoordinateOperationDetails () const
	Returns the transform details representing the coordinate operation which is being used to transform coordinates. More...

bool	isShortCircuited () const
	Returns `true` if the transform short circuits because the source and destination are equivalent. More...

bool	isValid () const
	Returns `true` if the coordinate transform is valid, ie both the source and destination CRS have been set and are valid. More...

QgsCoordinateTransform &	operator= (const QgsCoordinateTransform &o)
	Assignment operator. More...

double	scaleFactor (const QgsRectangle &referenceExtent) const
	Computes an estimated conversion factor between source and destination units: More...

void	setAllowFallbackTransforms (bool allowed)
	Sets whether "ballpark" fallback transformations can be used in the case that the specified coordinate operation fails (such as when coordinates from outside a required grid shift file are transformed). More...

void	setBallparkTransformsAreAppropriate (bool appropriate)
	Sets whether approximate "ballpark" results are appropriate for this coordinate transform. More...

void	setContext (const QgsCoordinateTransformContext &context)
	Sets the context in which the coordinate transform should be calculated. More...

void	setCoordinateOperation (const QString &operation) const
	Sets a Proj string representing the coordinate operation which will be used to transform coordinates. More...

void	setDestinationCrs (const QgsCoordinateReferenceSystem &crs)
	Sets the destination coordinate reference system. More...

Q_DECL_DEPRECATED void	setDestinationDatumTransformId (int datumId)
	Sets the datumId ID of the datum transform to use when projecting to the destination CRS. More...

void	setSourceCrs (const QgsCoordinateReferenceSystem &crs)
	Sets the source coordinate reference system. More...

Q_DECL_DEPRECATED void	setSourceDatumTransformId (int datumId)
	Sets the datumId ID of the datum transform to use when projecting from the source CRS. More...

QgsCoordinateReferenceSystem	sourceCrs () const
	Returns the source coordinate reference system, which the transform will transform coordinates from. More...

Q_DECL_DEPRECATED int	sourceDatumTransformId () const
	Returns the ID of the datum transform to use when projecting from the source CRS. More...

QgsPointXY	transform (const QgsPointXY &point, TransformDirection direction=ForwardTransform) const SIP_THROW(QgsCsException)
	Transform the point from the source CRS to the destination CRS. More...

QgsRectangle	transform (const QgsRectangle &rectangle, TransformDirection direction=ForwardTransform) const SIP_THROW(QgsCsException)
	Transforms a rectangle to the destination CRS. More...

QgsVector3D	transform (const QgsVector3D &point, TransformDirection direction=ForwardTransform) const
	Transform the point specified in 3D coordinates from the source CRS to the destination CRS. More...

QgsPointXY	transform (double x, double y, TransformDirection direction=ForwardTransform) const
	Transform the point specified by x,y from the source CRS to the destination CRS. More...

QgsRectangle	transformBoundingBox (const QgsRectangle &rectangle, TransformDirection direction=ForwardTransform, bool handle180Crossover=false) const SIP_THROW(QgsCsException)
	Transforms a rectangle from the source CRS to the destination CRS. More...

void	transformCoords (int numPoint, double x, double y, double *z, TransformDirection direction=ForwardTransform) const SIP_THROW(QgsCsException)
	Transform an array of coordinates to the destination CRS. More...

void	transformInPlace (double &x, double &y, double &z, TransformDirection direction=ForwardTransform) const SIP_THROW(QgsCsException)
	Transforms an array of x, y and z double coordinates in place, from the source CRS to the destination CRS. More...

void	transformInPlace (float &x, float &y, double &z, TransformDirection direction=ForwardTransform) const
	Transforms an array of x, y and z float coordinates in place, from the source CRS to the destination CRS. More...

void	transformInPlace (float &x, float &y, float &z, TransformDirection direction=ForwardTransform) const
	Transforms an array of x, y and z float coordinates in place, from the source CRS to the destination CRS. More...

void	transformInPlace (QVector< double > &x, QVector< double > &y, QVector< double > &z, TransformDirection direction=ForwardTransform) const
	Transforms a vector of x, y and z double coordinates in place, from the source CRS to the destination CRS. More...

void	transformInPlace (QVector< float > &x, QVector< float > &y, QVector< float > &z, TransformDirection direction=ForwardTransform) const
	Transforms a vector of x, y and z float coordinates in place, from the source CRS to the destination CRS. More...

void	transformPolygon (QPolygonF &polygon, TransformDirection direction=ForwardTransform) const SIP_THROW(QgsCsException)
	Transforms a polygon to the destination coordinate system. More...

Static Public Member Functions
static void	invalidateCache (bool disableCache=false)
	Clears the internal cache used to initialize QgsCoordinateTransform objects. More...

static void	setCustomCoordinateOperationCreationErrorHandler (const std::function< void(const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs, const QString &error)> &handler)
	Sets a custom handler to use when a coordinate transform was required between sourceCrs and destinationCrs, yet the coordinate operation could not be created. More...

static void	setCustomMissingGridUsedByContextHandler (const std::function< void(const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs, const QgsDatumTransform::TransformDetails &desiredOperation)> &handler)
	Sets a custom handler to use when a coordinate operation was specified for use between sourceCrs and destinationCrs by the transform context, yet the coordinate operation could not be created. More...

static void	setCustomMissingPreferredGridHandler (const std::function< void(const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs, const QgsDatumTransform::TransformDetails &preferredOperation, const QgsDatumTransform::TransformDetails &availableOperation)> &handler)
	Sets a custom handler to use when a coordinate transform is created between sourceCrs and destinationCrs, yet a preferred (more accurate?) operation is available which could not be created on the system (e.g. More...

static void	setCustomMissingRequiredGridHandler (const std::function< void(const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs, const QgsDatumTransform::GridDetails &grid)> &handler)
	Sets a custom handler to use when a coordinate transform is created between sourceCrs and destinationCrs, yet the coordinate operation requires a transform grid which is not present on the system. More...

static void	setFallbackOperationOccurredHandler (const std::function< void(const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs, const QString &desiredOperation)> &handler)
	Sets a custom handler to use when the desired coordinate operation for use between sourceCrs and destinationCrs failed and an alternative fallback operation was utilized instead. More...

Detailed Description

Class for doing transforms between two map coordinate systems.

This class can convert map coordinates to a different coordinate reference system. It is normally associated with a map layer and is used to transform between the layer's coordinate system and the coordinate system of the map canvas, although it can be used in a more general sense to transform coordinates.

When used to transform between a layer and the map canvas, all references to source and destination coordinate systems refer to layer and map canvas respectively. All operations are from the perspective of the layer. For example, a forward transformation transforms coordinates from the layer's coordinate system to the map canvas.

Note: Since QGIS 3.0 QgsCoordinateReferenceSystem objects are implicitly shared.

See also: QgsDatumTransform; QgsCoordinateTransformContext

Definition at line 53 of file qgscoordinatetransform.h.

Member Enumeration Documentation

◆ TransformDirection

enum QgsCoordinateTransform::TransformDirection

Enum used to indicate the direction (forward or inverse) of the transform.

Enumerator
ForwardTransform	Transform from source to destination CRS.
ReverseTransform	Transform from destination to source CRS.

Definition at line 59 of file qgscoordinatetransform.h.

Constructor & Destructor Documentation

◆ QgsCoordinateTransform() [1/5]

QgsCoordinateTransform::QgsCoordinateTransform ( )

Default constructor, creates an invalid QgsCoordinateTransform.

Definition at line 60 of file qgscoordinatetransform.cpp.

◆ QgsCoordinateTransform() [2/5]

QgsCoordinateTransform::QgsCoordinateTransform	(	const QgsCoordinateReferenceSystem &	source,
		const QgsCoordinateReferenceSystem &	destination,
		const QgsCoordinateTransformContext &	context
	)

explicit

Constructs a QgsCoordinateTransform to transform from the source to destination coordinate reference system.

The context argument specifies the context under which the transform will be applied, and is used for calculating necessary datum transforms to utilize.

Python scripts should generally use the constructor variant which accepts a QgsProject instance instead of this constructor.

Warning: Do NOT use an empty/default constructed QgsCoordinateTransformContext() object when creating QgsCoordinateTransform objects. This prevents correct datum transform handling and may result in inaccurate transformations. Always ensure that the QgsCoordinateTransformContext object is correctly retrieved based on the current code context, or use the constructor variant which accepts a QgsProject argument instead.

Since: QGIS 3.0

Definition at line 65 of file qgscoordinatetransform.cpp.

◆ QgsCoordinateTransform() [3/5]

QgsCoordinateTransform::QgsCoordinateTransform	(	const QgsCoordinateReferenceSystem &	source,
		const QgsCoordinateReferenceSystem &	destination,
		const QgsProject *	project
	)

explicit

Constructs a QgsCoordinateTransform to transform from the source to destination coordinate reference system, when used with the given project.

No reference to project is stored or utilized outside of the constructor, and it is used to retrieve the project's transform context only.

Python scripts should utilize the QgsProject.instance() project instance when creating QgsCoordinateTransform. This will ensure that any datum transforms defined in the project will be correctly respected during coordinate transforms. E.g.

transform = QgsCoordinateTransform(QgsCoordinateReferenceSystem("EPSG:3111"),

QgsCoordinateReferenceSystem("EPSG:4326"), QgsProject.instance())

QgsCoordinateReferenceSystem

This class represents a coordinate reference system (CRS).

Definition: qgscoordinatereferencesystem.h:210

QgsCoordinateTransform

Class for doing transforms between two map coordinate systems.

Definition: qgscoordinatetransform.h:54

QgsProject::instance

static QgsProject * instance()

Returns the QgsProject singleton instance.

Definition: qgsproject.cpp:501

Since: QGIS 3.0

Definition at line 89 of file qgscoordinatetransform.cpp.

◆ QgsCoordinateTransform() [4/5]

QgsCoordinateTransform::QgsCoordinateTransform	(	const QgsCoordinateReferenceSystem &	source,
		const QgsCoordinateReferenceSystem &	destination,
		int	sourceDatumTransformId,
		int	destinationDatumTransformId
	)

explicit

Constructs a QgsCoordinateTransform to transform from the source to destination coordinate reference system, with the specified datum transforms (see QgsDatumTransform).

Since: QGIS 3.0

Definition at line 114 of file qgscoordinatetransform.cpp.

◆ QgsCoordinateTransform() [5/5]

QgsCoordinateTransform::QgsCoordinateTransform ( const QgsCoordinateTransform & o )

Copy constructor.

Definition at line 137 of file qgscoordinatetransform.cpp.

◆ ~QgsCoordinateTransform()

QgsCoordinateTransform::~QgsCoordinateTransform ( )

Definition at line 158 of file qgscoordinatetransform.cpp.

Member Function Documentation

◆ allowFallbackTransforms()

bool QgsCoordinateTransform::allowFallbackTransforms ( ) const

Returns whether "ballpark" fallback transformations will be used in the case that the specified coordinate operation fails (such as when coordinates from outside a required grid shift file are transformed).

See fallbackOperationOccurred() for further details.

Note: Requires Proj 6.0 or later. Builds based on earlier Proj versions will ignore this setting.

See also: setAllowFallbackTransforms(); setBallparkTransformsAreAppropriate()

Since: QGIS 3.12

Definition at line 949 of file qgscoordinatetransform.cpp.

◆ context()

QgsCoordinateTransformContext QgsCoordinateTransform::context ( ) const

Returns the context in which the coordinate transform will be calculated.

See also: setContext()

Since: QGIS 3.4

Definition at line 225 of file qgscoordinatetransform.cpp.

◆ coordinateOperation()

QString QgsCoordinateTransform::coordinateOperation ( ) const

Returns a Proj string representing the coordinate operation which will be used to transform coordinates.

Note: The string returned by this method gives the desired coordinate operation string, based on the state of the QgsCoordinateTransformContext object given in the QgsCoordinateTransform's constructor. It may be an empty string if no explicit coordinate operation is required. In order to determine the ACTUAL coordinate operation which is being used by the transform, use the instantiatedCoordinateOperationDetails() call instead.; Requires Proj 6.0 or later. Builds based on earlier Proj versions will always return an empty string, and the deprecated sourceDatumTransformId() or destinationDatumTransformId() methods should be used instead.

See also: instantiatedCoordinateOperationDetails(); setCoordinateOperation()

Since: QGIS 3.8

Definition at line 921 of file qgscoordinatetransform.cpp.

◆ destinationCrs()

QgsCoordinateReferenceSystem QgsCoordinateTransform::destinationCrs ( ) const

Returns the destination coordinate reference system, which the transform will transform coordinates to.

See also: setDestinationCrs(); sourceCrs()

Definition at line 235 of file qgscoordinatetransform.cpp.

◆ destinationDatumTransformId()

int QgsCoordinateTransform::destinationDatumTransformId ( ) const

Returns the ID of the datum transform to use when projecting to the destination CRS.

This is usually calculated automatically from the transform's QgsCoordinateTransformContext, but can be manually overwritten by a call to setDestinationDatumTransformId().

See also: QgsDatumTransform; setDestinationDatumTransformId(); sourceDatumTransformId()

Deprecated:: Unused on builds based on Proj 6.0 or later

Definition at line 1103 of file qgscoordinatetransform.cpp.

◆ disableFallbackOperationHandler()

void QgsCoordinateTransform::disableFallbackOperationHandler ( bool disabled )

Sets whether the default fallback operation handler is disabled for this transform instance.

If the default handler is disabled then it is possible to determine whether a fallback operation occurred by testing fallbackOperationOccurred() immediately after a transformation.

Warning: This setting applies to a single instance of a coordinate transform only, and is not copied when a coordinate transform object is copied or assigned.

Note: Requires Proj 6.0 or later. Builds based on earlier Proj versions will never perform fallback operations.

See also: fallbackOperationOccurred()

Since: QGIS 3.12

Definition at line 959 of file qgscoordinatetransform.cpp.

◆ fallbackOperationOccurred()

bool QgsCoordinateTransform::fallbackOperationOccurred ( ) const

Returns true if a fallback operation occurred for the most recent transform.

Note: Requires Proj 6.0 or later. Builds based on earlier Proj versions will never perform fallback operations.

See also: disableFallbackOperationHandler()

Since: QGIS 3.12

Definition at line 964 of file qgscoordinatetransform.cpp.

◆ instantiatedCoordinateOperationDetails()

QgsDatumTransform::TransformDetails QgsCoordinateTransform::instantiatedCoordinateOperationDetails ( ) const

Returns the transform details representing the coordinate operation which is being used to transform coordinates.

This may differ from the result returned by coordinateOperation() if the desired coordinate operation was not successfully instantiated.

Note: Requires Proj 6.0 or later. Builds based on earlier Proj versions will always return an empty result, and the deprecated sourceDatumTransformId() or destinationDatumTransformId() methods should be used instead.

See also: coordinateOperation()

Since: QGIS 3.10.2

Definition at line 926 of file qgscoordinatetransform.cpp.

◆ invalidateCache()

void QgsCoordinateTransform::invalidateCache ( bool disableCache = false )

static

Clears the internal cache used to initialize QgsCoordinateTransform objects.

This should be called whenever the srs database has been modified in order to ensure that outdated CRS transforms are not created.

If disableCache is true then the inbuilt cache will be completely disabled. This argument is for internal use only.

Since: QGIS 3.0

Definition at line 1118 of file qgscoordinatetransform.cpp.

◆ isShortCircuited()

bool QgsCoordinateTransform::isShortCircuited ( ) const

Returns true if the transform short circuits because the source and destination are equivalent.

Definition at line 916 of file qgscoordinatetransform.cpp.

◆ isValid()

bool QgsCoordinateTransform::isValid ( ) const

Returns true if the coordinate transform is valid, ie both the source and destination CRS have been set and are valid.

Since: QGIS 3.0

Definition at line 911 of file qgscoordinatetransform.cpp.

◆ operator=()

QgsCoordinateTransform & QgsCoordinateTransform::operator= ( const QgsCoordinateTransform & o )

Assignment operator.

Definition at line 147 of file qgscoordinatetransform.cpp.

◆ scaleFactor()

double QgsCoordinateTransform::scaleFactor ( const QgsRectangle & referenceExtent ) const

Computes an estimated conversion factor between source and destination units:

sourceUnits * scaleFactor = destinationUnits

Parameters

referenceExtent A reference extent based on which to perform the computation

Since: QGIS 3.4

Definition at line 1158 of file qgscoordinatetransform.cpp.

◆ setAllowFallbackTransforms()

void QgsCoordinateTransform::setAllowFallbackTransforms ( bool allowed )

Sets whether "ballpark" fallback transformations can be used in the case that the specified coordinate operation fails (such as when coordinates from outside a required grid shift file are transformed).

See fallbackOperationOccurred() for further details.

Note: Requires Proj 6.0 or later. Builds based on earlier Proj versions will ignore this setting.

Warning: If setBallparkTransformsAreAppropriate() is set to true, this setting will be ignored and fallback transformations will always be permitted.

See also: allowFallbackTransforms(); setBallparkTransformsAreAppropriate()

Since: QGIS 3.12

Definition at line 943 of file qgscoordinatetransform.cpp.

◆ setBallparkTransformsAreAppropriate()

void QgsCoordinateTransform::setBallparkTransformsAreAppropriate ( bool appropriate )

Sets whether approximate "ballpark" results are appropriate for this coordinate transform.

When a coordinate transform is only being used to generate ballpark results then the appropriate argument should be set to true. This indicates that its perfectable acceptable (and even expected!) for the transform to use fallback coordinate operations in the case that the preferred or user-specified operation fails (such as when coordinates from outside of a grid shift file's extent are transformed).

When appropriate is true, then no warnings will be generated when the transform falls back to a default operation, which may introduce inaccuracies when compared to the default/specified coordinate operation.

This should be set when a transform expects that coordinates outside of the direct area of use while be transformed, e.g. when transforming from a global extent to a CRS with a localized area of use.

If appropriate is false (the default behavior), then transforms MAY STILL fallback to default operations when the preferred or user-specified operation fails, however whenever this occurs a user-visible warning will be generated.

If appropriate is true, then this setting overrides allowFallbackTransforms() and fallback transforms will always be allowed when required.

Warning: This setting applies to a single instance of a coordinate transform only, and is not copied when a coordinate transform object is copied or assigned.

Note: Requires Proj 6.0 or later. Builds based on earlier Proj versions will ignore this setting.

Since: QGIS 3.12

Definition at line 954 of file qgscoordinatetransform.cpp.

◆ setContext()

void QgsCoordinateTransform::setContext ( const QgsCoordinateTransformContext & context )

Sets the context in which the coordinate transform should be calculated.

See also: context()

Since: QGIS 3.0

Definition at line 201 of file qgscoordinatetransform.cpp.

◆ setCoordinateOperation()

void QgsCoordinateTransform::setCoordinateOperation ( const QString & operation ) const

Sets a Proj string representing the coordinate operation which will be used to transform coordinates.

Warning: It is the caller's responsibility to ensure that operation is a valid Proj coordinate operation string.

Note: Requires Proj 6.0 or later. Builds based on earlier Proj versions will ignore this setting, and the deprecated setSourceDatumTransformId() or setDestinationDatumTransformId() methods should be used instead.

See also: coordinateOperation()

Since: QGIS 3.8

Definition at line 936 of file qgscoordinatetransform.cpp.

◆ setCustomCoordinateOperationCreationErrorHandler()

void QgsCoordinateTransform::setCustomCoordinateOperationCreationErrorHandler ( const std::function< void(const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs, const QString &error)> & handler )

static

Sets a custom handler to use when a coordinate transform was required between sourceCrs and destinationCrs, yet the coordinate operation could not be created.

The error argument specifies the error message obtained.

See also: setCustomMissingRequiredGridHandler(); setCustomMissingPreferredGridHandler(); setCustomMissingGridUsedByContextHandler()

Note: Not available in Python bindings

Since: QGIS 3.8

Definition at line 1179 of file qgscoordinatetransform.cpp.

◆ setCustomMissingGridUsedByContextHandler()

void QgsCoordinateTransform::setCustomMissingGridUsedByContextHandler ( const std::function< void(const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs, const QgsDatumTransform::TransformDetails &desiredOperation)> & handler )

static

Sets a custom handler to use when a coordinate operation was specified for use between sourceCrs and destinationCrs by the transform context, yet the coordinate operation could not be created.

The desiredOperation argument specifies the desired transform details as specified by the context.

See also: setCustomMissingRequiredGridHandler(); setCustomMissingPreferredGridHandler(); setCustomCoordinateOperationCreationErrorHandler()

Note: Not available in Python bindings

Since: QGIS 3.8

Definition at line 1184 of file qgscoordinatetransform.cpp.

◆ setCustomMissingPreferredGridHandler()

void QgsCoordinateTransform::setCustomMissingPreferredGridHandler ( const std::function< void(const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs, const QgsDatumTransform::TransformDetails &preferredOperation, const QgsDatumTransform::TransformDetails &availableOperation)> & handler )

static

Sets a custom handler to use when a coordinate transform is created between sourceCrs and destinationCrs, yet a preferred (more accurate?) operation is available which could not be created on the system (e.g.

due to missing transform grids).

preferredOperation gives the details of the preferred coordinate operation, and availableOperation gives the details of the actual operation to be used during the transform.

See also: setCustomMissingRequiredGridHandler(); setCustomCoordinateOperationCreationErrorHandler(); setCustomMissingGridUsedByContextHandler()

Note: Not available in Python bindings

Since: QGIS 3.8

Definition at line 1174 of file qgscoordinatetransform.cpp.

◆ setCustomMissingRequiredGridHandler()

void QgsCoordinateTransform::setCustomMissingRequiredGridHandler ( const std::function< void(const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs, const QgsDatumTransform::GridDetails &grid)> & handler )

static

Sets a custom handler to use when a coordinate transform is created between sourceCrs and destinationCrs, yet the coordinate operation requires a transform grid which is not present on the system.

See also: setCustomMissingPreferredGridHandler(); setCustomCoordinateOperationCreationErrorHandler(); setCustomMissingGridUsedByContextHandler()

Note: Not available in Python bindings

Since: QGIS 3.8

Definition at line 1169 of file qgscoordinatetransform.cpp.

◆ setDestinationCrs()

void QgsCoordinateTransform::setDestinationCrs ( const QgsCoordinateReferenceSystem & crs )

Sets the destination coordinate reference system.

Parameters

crs	CRS to transform coordinates to

See also: destinationCrs(); setSourceCrs()

Definition at line 180 of file qgscoordinatetransform.cpp.

◆ setDestinationDatumTransformId()

void QgsCoordinateTransform::setDestinationDatumTransformId ( int datumId )

Sets the datumId ID of the datum transform to use when projecting to the destination CRS.

This is usually calculated automatically from the transform's QgsCoordinateTransformContext. Calling this method will overwrite any automatically calculated datum transform.

See also: QgsDatumTransform; destinationDatumTransformId(); setSourceDatumTransformId()

Deprecated:: Unused on builds based on Proj 6.0 or later

Definition at line 1110 of file qgscoordinatetransform.cpp.

◆ setFallbackOperationOccurredHandler()

void QgsCoordinateTransform::setFallbackOperationOccurredHandler ( const std::function< void(const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs, const QString &desiredOperation)> & handler )

static

Sets a custom handler to use when the desired coordinate operation for use between sourceCrs and destinationCrs failed and an alternative fallback operation was utilized instead.

Since: QGIS 3.10.3

Definition at line 1189 of file qgscoordinatetransform.cpp.

◆ setSourceCrs()

void QgsCoordinateTransform::setSourceCrs ( const QgsCoordinateReferenceSystem & crs )

Sets the source coordinate reference system.

Parameters

crs	CRS to transform coordinates from

See also: sourceCrs(); setDestinationCrs()

Definition at line 160 of file qgscoordinatetransform.cpp.

◆ setSourceDatumTransformId()

void QgsCoordinateTransform::setSourceDatumTransformId ( int datumId )

Sets the datumId ID of the datum transform to use when projecting from the source CRS.

This is usually calculated automatically from the transform's QgsCoordinateTransformContext. Calling this method will overwrite any automatically calculated datum transform.

See also: QgsDatumTransform; sourceDatumTransformId(); setDestinationDatumTransformId()

Deprecated:: Unused on builds based on Proj 6.0 or later

Definition at line 1095 of file qgscoordinatetransform.cpp.

◆ sourceCrs()

QgsCoordinateReferenceSystem QgsCoordinateTransform::sourceCrs ( ) const

Returns the source coordinate reference system, which the transform will transform coordinates from.

See also: setSourceCrs(); destinationCrs()

Definition at line 230 of file qgscoordinatetransform.cpp.

◆ sourceDatumTransformId()

int QgsCoordinateTransform::sourceDatumTransformId ( ) const

Returns the ID of the datum transform to use when projecting from the source CRS.

This is usually calculated automatically from the transform's QgsCoordinateTransformContext, but can be manually overwritten by a call to setSourceDatumTransformId().

See also: QgsDatumTransform; setSourceDatumTransformId(); destinationDatumTransformId()

Deprecated:: Unused on builds based on Proj 6.0 or later

Definition at line 1088 of file qgscoordinatetransform.cpp.

◆ transform() [1/4]

QgsPointXY QgsCoordinateTransform::transform	(	const QgsPointXY &	point,
		TransformDirection	direction = `ForwardTransform`
	)		const

Transform the point from the source CRS to the destination CRS.

If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS.

Parameters

point	point to transform
direction	transform direction (defaults to ForwardTransform)

Returns: transformed point

Definition at line 240 of file qgscoordinatetransform.cpp.

◆ transform() [2/4]

QgsRectangle QgsCoordinateTransform::transform	(	const QgsRectangle &	rectangle,
		TransformDirection	direction = `ForwardTransform`
	)		const

Transforms a rectangle to the destination CRS.

If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS.

Parameters

rectangle	rectangle to transform
direction	transform direction (defaults to ForwardTransform)

Returns: transformed rectangle

Definition at line 278 of file qgscoordinatetransform.cpp.

◆ transform() [3/4]

QgsVector3D QgsCoordinateTransform::transform	(	const QgsVector3D &	point,
		TransformDirection	direction = `ForwardTransform`
	)		const

Transform the point specified in 3D coordinates from the source CRS to the destination CRS.

If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS.

Parameters

point	coordinates of point to transform
direction	transform direction (defaults to ForwardTransform)

Returns: transformed point

Since: QGIS 3.18

Definition at line 314 of file qgscoordinatetransform.cpp.

◆ transform() [4/4]

QgsPointXY QgsCoordinateTransform::transform	(	double	x,
		double	y = `0.0`,
		TransformDirection	direction = `ForwardTransform`
	)		const

Transform the point specified by x,y from the source CRS to the destination CRS.

If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS.

Parameters

x	x coordinate of point to transform
y	y coordinate of point to transform
direction	transform direction (defaults to ForwardTransform)

Returns: transformed point

Definition at line 264 of file qgscoordinatetransform.cpp.

◆ transformBoundingBox()

QgsRectangle QgsCoordinateTransform::transformBoundingBox	(	const QgsRectangle &	rectangle,
		TransformDirection	direction = `ForwardTransform`,
		bool	handle180Crossover = `false`
	)		const

Transforms a rectangle from the source CRS to the destination CRS.

If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS. This method assumes that the rectangle is a bounding box, and creates a bounding box in the projected CRS, such that all points from the source rectangle are within the returned rectangle.

Parameters

rectangle	rectangle to transform
direction	transform direction (defaults to ForwardTransform)
handle180Crossover	set to `true` if destination CRS is geographic and handling of extents crossing the 180 degree longitude line is required

Returns: rectangle in destination CRS

Definition at line 530 of file qgscoordinatetransform.cpp.

◆ transformCoords()

void QgsCoordinateTransform::transformCoords	(	int	numPoint,
		double *	x,
		double *	y,
		double *	z,
		TransformDirection	direction = `ForwardTransform`
	)		const

Transform an array of coordinates to the destination CRS.

If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS.

Parameters

numPoint	number of coordinates in arrays
x	array of x coordinates to transform
y	array of y coordinates to transform
z	array of z coordinates to transform
direction	transform direction (defaults to ForwardTransform)

Definition at line 649 of file qgscoordinatetransform.cpp.

◆ transformInPlace() [1/5]

void QgsCoordinateTransform::transformInPlace	(	double &	x,
		double &	y,
		double &	z,
		TransformDirection	direction = `ForwardTransform`
	)		const

Transforms an array of x, y and z double coordinates in place, from the source CRS to the destination CRS.

If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS.

Parameters

x	array of x coordinates of points to transform
y	array of y coordinates of points to transform
z	array of z coordinates of points to transform. The z coordinates of the points must represent height relative to the vertical datum of the source CRS (generally ellipsoidal heights) and must be expressed in its vertical units (generally meters)
direction	transform direction (defaults to ForwardTransform)

Definition at line 332 of file qgscoordinatetransform.cpp.

◆ transformInPlace() [2/5]

void QgsCoordinateTransform::transformInPlace	(	float &	x,
		float &	y,
		double &	z,
		TransformDirection	direction = `ForwardTransform`
	)		const

Transforms an array of x, y and z float coordinates in place, from the source CRS to the destination CRS.

If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS.

Parameters

x	array of x coordinates of points to transform
y	array of y coordinates of points to transform
z	array of z coordinates of points to transform. The z coordinates of the points must represent height relative to the vertical datum of the source CRS (generally ellipsoidal heights) and must be expressed in its vertical units (generally meters)
direction	transform direction (defaults to ForwardTransform)

Note: not available in Python bindings

Definition at line 353 of file qgscoordinatetransform.cpp.

◆ transformInPlace() [3/5]

void QgsCoordinateTransform::transformInPlace	(	float &	x,
		float &	y,
		float &	z,
		TransformDirection	direction = `ForwardTransform`
	)		const

Transforms an array of x, y and z float coordinates in place, from the source CRS to the destination CRS.

If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS.

Parameters

x	array of x coordinates of points to transform
y	array of y coordinates of points to transform
z	array of z coordinates of points to transform. The z coordinates of the points must represent height relative to the vertical datum of the source CRS (generally ellipsoidal heights) and must be expressed in its vertical units (generally meters)
direction	transform direction (defaults to ForwardTransform)

Note: not available in Python bindings

Definition at line 362 of file qgscoordinatetransform.cpp.

◆ transformInPlace() [4/5]

void QgsCoordinateTransform::transformInPlace	(	QVector< double > &	x,
		QVector< double > &	y,
		QVector< double > &	z,
		TransformDirection	direction = `ForwardTransform`
	)		const

Transforms a vector of x, y and z double coordinates in place, from the source CRS to the destination CRS.

If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS.

Parameters

x	vector of x coordinates of points to transform
y	vector of y coordinates of points to transform
z	vector of z coordinates of points to transform. The z coordinates of the points must represent height relative to the vertical datum of the source CRS (generally ellipsoidal heights) and must be expressed in its vertical units (generally meters)
direction	transform direction (defaults to ForwardTransform)

Note: not available in Python bindings

Definition at line 441 of file qgscoordinatetransform.cpp.

◆ transformInPlace() [5/5]

void QgsCoordinateTransform::transformInPlace	(	QVector< float > &	x,
		QVector< float > &	y,
		QVector< float > &	z,
		TransformDirection	direction = `ForwardTransform`
	)		const

Transforms a vector of x, y and z float coordinates in place, from the source CRS to the destination CRS.

If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS.

Parameters

x	vector of x coordinates of points to transform
y	vector of y coordinates of points to transform
z	vector of z coordinates of points to transform. The z coordinates of the points must represent height relative to the vertical datum of the source CRS (generally ellipsoidal heights) and must be expressed in its vertical units (generally meters)
direction	transform direction (defaults to ForwardTransform)

Note: not available in Python bindings

Definition at line 469 of file qgscoordinatetransform.cpp.

◆ transformPolygon()

void QgsCoordinateTransform::transformPolygon	(	QPolygonF &	polygon,
		TransformDirection	direction = `ForwardTransform`
	)		const

Transforms a polygon to the destination coordinate system.

Parameters

polygon	polygon to transform (occurs in place)
direction	transform direction (defaults to forward transformation)

Definition at line 389 of file qgscoordinatetransform.cpp.

The documentation for this class was generated from the following files:

/build/qgis-3.18.1+99unstable/src/core/qgscoordinatetransform.h
/build/qgis-3.18.1+99unstable/src/core/qgscoordinatetransform.cpp

Public Types

Public Member Functions

Static Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ TransformDirection

Constructor & Destructor Documentation

◆ QgsCoordinateTransform() [1/5]

◆ QgsCoordinateTransform() [2/5]

◆ QgsCoordinateTransform() [3/5]

◆ QgsCoordinateTransform() [4/5]

◆ QgsCoordinateTransform() [5/5]

◆ ~QgsCoordinateTransform()

Member Function Documentation

◆ allowFallbackTransforms()

◆ context()

◆ coordinateOperation()

◆ destinationCrs()

◆ destinationDatumTransformId()

◆ disableFallbackOperationHandler()

◆ fallbackOperationOccurred()

◆ instantiatedCoordinateOperationDetails()

◆ invalidateCache()

◆ isShortCircuited()

◆ isValid()

◆ operator=()

◆ scaleFactor()

◆ setAllowFallbackTransforms()

◆ setBallparkTransformsAreAppropriate()

◆ setContext()

◆ setCoordinateOperation()

◆ setCustomCoordinateOperationCreationErrorHandler()

◆ setCustomMissingGridUsedByContextHandler()

◆ setCustomMissingPreferredGridHandler()

◆ setCustomMissingRequiredGridHandler()

◆ setDestinationCrs()

◆ setDestinationDatumTransformId()

◆ setFallbackOperationOccurredHandler()

◆ setSourceCrs()

◆ setSourceDatumTransformId()

◆ sourceCrs()

◆ sourceDatumTransformId()

◆ transform() [1/4]

◆ transform() [2/4]

◆ transform() [3/4]

◆ transform() [4/4]

◆ transformBoundingBox()

◆ transformCoords()

◆ transformInPlace() [1/5]

◆ transformInPlace() [2/5]

◆ transformInPlace() [3/5]

◆ transformInPlace() [4/5]

◆ transformInPlace() [5/5]

◆ transformPolygon()