QgsGcpTransformerInterface Class Reference

An interface for Ground Control Points (GCP) based transformations. More...

#include <qgsgcptransformer.h>

Inheritance diagram for QgsGcpTransformerInterface:

Public Types
enum class	TransformMethod : int {   Linear , Helmert , PolynomialOrder1 , PolynomialOrder2 ,   PolynomialOrder3 , ThinPlateSpline , Projective , InvalidTransform = 65535 }
	Available transformation methods. More...

Public Member Functions
	QgsGcpTransformerInterface ()=default
	QgsGcpTransformerInterface (const QgsGcpTransformerInterface &other)=delete
	QgsGcpTransformerInterface cannot be copied - use clone() instead.
virtual	~QgsGcpTransformerInterface ()=default
virtual QgsGcpTransformerInterface *	clone () const =0
	Clones the transformer, returning a new copy of the transformer with the same parameters as this one.
virtual GDALTransformerFunc	GDALTransformer () const =0
	Returns function pointer to the GDALTransformer function.
virtual void *	GDALTransformerArgs () const =0
	Returns pointer to the GDALTransformer arguments.
virtual TransformMethod	method () const =0
	Returns the transformation method.
virtual int	minimumGcpCount () const =0
	Returns the minimum number of Ground Control Points (GCPs) required for parameter fitting.
QgsGcpTransformerInterface &	operator= (const QgsGcpTransformerInterface &other)=delete
	QgsGcpTransformerInterface cannot be copied - use clone() instead.
bool	transform (double &x, double &y, bool inverseTransform=false) const
	Transforms the point (x, y) from source to destination coordinates.
virtual bool	updateParametersFromGcps (const QVector< QgsPointXY > &sourceCoordinates, const QVector< QgsPointXY > &destinationCoordinates, bool invertYAxis=false)=0
	Fits transformation parameters using the specified Ground Control Points (GCPs) lists of source and destination coordinates.

Static Public Member Functions
static QgsGcpTransformerInterface *	create (TransformMethod method)
	Creates a new QgsGcpTransformerInterface subclass representing the specified transform method.
static QgsGcpTransformerInterface *	createFromParameters (TransformMethod method, const QVector< QgsPointXY > &sourceCoordinates, const QVector< QgsPointXY > &destinationCoordinates)
	Creates a new QgsGcpTransformerInterface subclass representing the specified transform method, initialized using the given lists of source and destination coordinates.
static QString	methodToString (TransformMethod method)
	Returns a translated string representing the specified transform method.

Detailed Description

An interface for Ground Control Points (GCP) based transformations.

QgsGcpTransformerInterface implementations are able to transform point locations based on a transformation method and a list of GCPs.

Since

QGIS 3.20

Definition at line 34 of file qgsgcptransformer.h.

Member Enumeration Documentation

TransformMethod

enum class QgsGcpTransformerInterface::TransformMethod : int

strong

Available transformation methods.

Enumerator
Linear	Linear transform.
Helmert	Helmert transform.
PolynomialOrder1	Polynomial order 1.
PolynomialOrder2	Polyonmial order 2.
PolynomialOrder3	Polynomial order.
ThinPlateSpline	Thin plate splines.
Projective	Projective.
InvalidTransform	Invalid transform.

Definition at line 43 of file qgsgcptransformer.h.

Constructor & Destructor Documentation

QgsGcpTransformerInterface() [1/2]

QgsGcpTransformerInterface::QgsGcpTransformerInterface ( )

default

~QgsGcpTransformerInterface()

virtual QgsGcpTransformerInterface::~QgsGcpTransformerInterface ( )

virtualdefault

QgsGcpTransformerInterface() [2/2]

QgsGcpTransformerInterface::QgsGcpTransformerInterface ( const QgsGcpTransformerInterface &  other )

delete

QgsGcpTransformerInterface cannot be copied - use clone() instead.

Member Function Documentation

clone()

virtual QgsGcpTransformerInterface * QgsGcpTransformerInterface::clone ( ) const

pure virtual

Clones the transformer, returning a new copy of the transformer with the same parameters as this one.

Caller takes ownership of the returned object.

Implemented in QgsLinearGeorefTransform, QgsHelmertGeorefTransform, QgsGDALGeorefTransform, and QgsProjectiveGeorefTransform.

create()

QgsGcpTransformerInterface * QgsGcpTransformerInterface::create ( QgsGcpTransformerInterface::TransformMethod  method )

static

Creates a new QgsGcpTransformerInterface subclass representing the specified transform method.

Caller takes ownership of the returned object.

Definition at line 71 of file qgsgcptransformer.cpp.

createFromParameters()

QgsGcpTransformerInterface * QgsGcpTransformerInterface::createFromParameters ( QgsGcpTransformerInterface::TransformMethod  method, const QVector< QgsPointXY > &  sourceCoordinates, const QVector< QgsPointXY > &  destinationCoordinates  )

static

Creates a new QgsGcpTransformerInterface subclass representing the specified transform method, initialized using the given lists of source and destination coordinates.

If the parameters cannot be fit to a transform nullptr will be returned.

Caller takes ownership of the returned object.

Definition at line 94 of file qgsgcptransformer.cpp.

GDALTransformer()

virtual GDALTransformerFunc QgsGcpTransformerInterface::GDALTransformer ( ) const

pure virtual

Returns function pointer to the GDALTransformer function.

Implemented in QgsLinearGeorefTransform, QgsHelmertGeorefTransform, QgsGDALGeorefTransform, and QgsProjectiveGeorefTransform.

GDALTransformerArgs()

virtual void * QgsGcpTransformerInterface::GDALTransformerArgs ( ) const

pure virtual

Returns pointer to the GDALTransformer arguments.

Implemented in QgsLinearGeorefTransform, QgsHelmertGeorefTransform, QgsGDALGeorefTransform, and QgsProjectiveGeorefTransform.

method()

virtual TransformMethod QgsGcpTransformerInterface::method ( ) const

pure virtual

Returns the transformation method.

Implemented in QgsLinearGeorefTransform, QgsHelmertGeorefTransform, QgsGDALGeorefTransform, and QgsProjectiveGeorefTransform.

methodToString()

QString QgsGcpTransformerInterface::methodToString ( QgsGcpTransformerInterface::TransformMethod  method )

static

Returns a translated string representing the specified transform method.

Definition at line 48 of file qgsgcptransformer.cpp.

minimumGcpCount()

virtual int QgsGcpTransformerInterface::minimumGcpCount ( ) const

pure virtual

Returns the minimum number of Ground Control Points (GCPs) required for parameter fitting.

Implemented in QgsLinearGeorefTransform, QgsHelmertGeorefTransform, QgsGDALGeorefTransform, and QgsProjectiveGeorefTransform.

operator=()

QgsGcpTransformerInterface & QgsGcpTransformerInterface::operator= ( const QgsGcpTransformerInterface &  other )

delete

QgsGcpTransformerInterface cannot be copied - use clone() instead.

transform()

bool QgsGcpTransformerInterface::transform	(	double &	x,
		double &	y,
		bool	inverseTransform = false
	)		const

Transforms the point (x, y) from source to destination coordinates.

If inverseTransform is set to true, the point will be transformed from the destination to the source.

Returns

true if transformation was successful.

Definition at line 30 of file qgsgcptransformer.cpp.

updateParametersFromGcps()

virtual bool QgsGcpTransformerInterface::updateParametersFromGcps ( const QVector< QgsPointXY > &  sourceCoordinates, const QVector< QgsPointXY > &  destinationCoordinates, bool  invertYAxis = false  )

pure virtual

Fits transformation parameters using the specified Ground Control Points (GCPs) lists of source and destination coordinates.

If invertYAxis is set to true then the y-axis of source coordinates will be inverted, e.g. to allow for transformation of raster layers with ascending top-to-bottom vertical axis coordinates.

Returns

true on success, false on failure

Implemented in QgsLinearGeorefTransform, QgsHelmertGeorefTransform, QgsGDALGeorefTransform, and QgsProjectiveGeorefTransform.

---

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

• /build/qgis-3.41.0+git20241119+45a0abf3bec+99sid/src/analysis/georeferencing/qgsgcptransformer.h
• /build/qgis-3.41.0+git20241119+45a0abf3bec+99sid/src/analysis/georeferencing/qgsgcptransformer.cpp