This class implements a geometry check. More...

#include <qgsgeometrycheck.h>

Inheritance diagram for QgsGeometryCheck:

[legend]

Classes
struct	Change
	Descripts a change to fix a geometry. More...

struct	LayerFeatureIds
	A list of layers and feature ids for each of these layers. More...

Public Types
typedef QMap< QString, QMap< QgsFeatureId, QList< QgsGeometryCheck::Change > > >	Changes
	A collection of changes. More...

enum	ChangeType { ChangeAdded, ChangeRemoved, ChangeChanged }
	Description of the type of a change. More...

enum	ChangeWhat { ChangeFeature, ChangePart, ChangeRing, ChangeNode }
	Description of a change to indicate at which level a change occurred. More...

enum	CheckType { FeatureNodeCheck, FeatureCheck, LayerCheck }
	The type of a check. More...

enum	Flag { AvailableInValidation = 1 << 1 }
	Flags for geometry checks. More...

Public Member Functions
	QgsGeometryCheck (const QgsGeometryCheckContext *context, const QVariantMap &configuration)
	Create a new geometry check. More...

virtual	~QgsGeometryCheck ()=default

virtual CheckType	checkType () const =0
	Returns the check type. More...

virtual void	collectErrors (const QMap< QString, QgsFeaturePool > &featurePools, QList< QgsGeometryCheckError > &errors, QStringList &messages, QgsFeedback *feedback, const LayerFeatureIds &ids=QgsGeometryCheck::LayerFeatureIds()) const =0
	The main worker method. More...

virtual QList< QgsWkbTypes::GeometryType >	compatibleGeometryTypes () const =0
	A list of geometry types for which this check can be performed. More...

template<class T >
T	configurationValue (const QString &name, const QVariant &defaultValue=QVariant())
	Returns the configuration value with the name, saved in the QGIS settings for this geometry check. More...

const QgsGeometryCheckContext *	context () const
	Returns the context. More...

virtual QString	description () const =0
	Returns a human readable description for this check. More...

virtual void	fixError (const QMap< QString, QgsFeaturePool > &featurePools, QgsGeometryCheckError error, int method, const QMap< QString, int > &mergeAttributeIndices, Changes &changes) const
	Fixes the error error with the specified method. More...

virtual QgsGeometryCheck::Flags	flags () const
	Flags for this geometry check. More...

virtual QString	id () const =0
	Returns an id for this check. More...

virtual bool	isCompatible (QgsVectorLayer *layer) const
	Returns if this geometry check is compatible with layer. More...

virtual void	prepare (const QgsGeometryCheckContext *context, const QVariantMap &configuration)
	Will be run in the main thread before collectErrors is called (which may be run from a background thread). More...

virtual QStringList	resolutionMethods () const =0
	Returns a list of descriptions for available resolutions for errors. More...

Protected Member Functions
QMap< QString, QgsFeatureIds >	allLayerFeatureIds (const QMap< QString, QgsFeaturePool *> &featurePools) const
	Returns all layers and feature ids. More...

void	deleteFeatureGeometryPart (const QMap< QString, QgsFeaturePool *> &featurePools, const QString &layerId, QgsFeature &feature, int partIdx, Changes &changes) const
	Deletes a part of a feature geometry. More...

void	deleteFeatureGeometryRing (const QMap< QString, QgsFeaturePool *> &featurePools, const QString &layerId, QgsFeature &feature, int partIdx, int ringIdx, Changes &changes) const
	Deletes a ring in a feature geometry. More...

void	replaceFeatureGeometryPart (const QMap< QString, QgsFeaturePool > &featurePools, const QString &layerId, QgsFeature &feature, int partIdx, QgsAbstractGeometry newPartGeom, Changes &changes) const
	Replaces a part in a feature geometry. More...

double	scaleFactor (const QPointer< QgsVectorLayer > &layer) const
	Determines the scale factor of a layer to the map coordinate reference system. More...

Protected Attributes
QVariantMap	mConfiguration

const QgsGeometryCheckContext *	mContext

Detailed Description

This class implements a geometry check.

Geometry checks run over a set of features and can detect errors like topological or other issues which are reported in the geometry validation panel in QGIS and help a user to create valid geometries.

Implementing a custom geometry check consists of the following parts

Writing the check

A new subclass of QgsGeometryCheck needs to be written and at least the following abstract methods need to be implemented:

compatibleGeometryTypes()

A list of geometry types to which this check applies
resolutionMethods()

A list of names for (automated) resolution methods that can be used to fix errors of this type
description()

A description for the geometry check.
id()

A unique id for this check.
checkType()

One of QgsGeometryCheck.LayerCheck, QgsGeometryCheck.FeatureCheck,QgsGeometryCheck.FeatureNodeCheck
collectErrors(featurePools, errors, messages, feedback, ids)

This method will be called to validate geometries. All geometries which should be validated are passed into this method with the parameter ids and should be retrieved from the available featurePools to make use of caching. New errors should be appended to the error list and other message strings to messages. The method needs to return a tuple (errors, messages).

Creating a geometry check factory

A Geometry check factory manages meta information for checks. There will always be one single geometry check factory created per check type, but it's possible that multiple QgsGeometryCheck instances are created and used in parallel.

A new subclass of QgsGeometryCheckFactory needs to be written and at least the following abstract methods need to be implemented:

createGeometryCheck(context, configuration)

Needs to return a new subclassed QgsGeometryCheck object that has been written in the previous step.
`id()

A unique id for this geometry check.
`description()

A description for this geometry check that can be presented to the user for more explanation.
QgsGeometryCheckFactory::isCompatible(layer)

Returns a boolean that determines if this check is available for a given layer. This often checks for the geometry type of the layer.
flags()

Returns additional flags for a geometry check. If unsure return QgsGeometryCheck.AvailableInValidation.
checkType()

Returns the type of this geometry check.

Registering the geometry check

Finally the geometry check factory needs to be registered in QGIS, so the system is aware of the available geometry checks.

# Make sure you always keep a
checkFactory = MyGeometryCheckFactory()
QgsAnalysis.geometryCheckRegistry().registerGeometryCheck(checkFactory)

Note: This class is a technology preview and unstable API.

Since: QGIS 3.4

Definition at line 125 of file qgsgeometrycheck.h.

Member Typedef Documentation

◆ Changes

typedef QMap<QString, QMap<QgsFeatureId, QList<QgsGeometryCheck::Change> > > QgsGeometryCheck::Changes

A collection of changes.

Grouped by layer id and feature id.

Definition at line 248 of file qgsgeometrycheck.h.

Member Enumeration Documentation

◆ ChangeType

enum QgsGeometryCheck::ChangeType

Description of the type of a change.

Since: Python bindings since QGIS 3.4

Enumerator
ChangeAdded	Something has been added.
ChangeRemoved	Something has been removed.
ChangeChanged	Something has been updated.

Definition at line 177 of file qgsgeometrycheck.h.

◆ ChangeWhat

enum QgsGeometryCheck::ChangeWhat

Description of a change to indicate at which level a change occurred.

Since: Python bindings since QGIS 3.4

Enumerator
ChangeFeature	This change happens on feature level.
ChangePart	This change happens on part level.
ChangeRing	This change happens on ring level.
ChangeNode	This change happens on node level.

Definition at line 164 of file qgsgeometrycheck.h.

◆ CheckType

enum QgsGeometryCheck::CheckType

The type of a check.

Since: Python bindings since QGIS 3.4

Enumerator
FeatureNodeCheck	The check controls individual nodes.
FeatureCheck	The check controls geometries as a whole.
LayerCheck	The check controls a whole layer (topology checks)

Definition at line 189 of file qgsgeometrycheck.h.

◆ Flag

enum QgsGeometryCheck::Flag

Flags for geometry checks.

Enumerator
AvailableInValidation	This geometry check should be available in layer validation on the vector layer peroperties.

Definition at line 199 of file qgsgeometrycheck.h.

Constructor & Destructor Documentation

◆ QgsGeometryCheck()

QgsGeometryCheck::QgsGeometryCheck	(	const QgsGeometryCheckContext *	context,
		const QVariantMap &	configuration
	)

Create a new geometry check.

Definition at line 29 of file qgsgeometrycheck.cpp.

◆ ~QgsGeometryCheck()

virtual QgsGeometryCheck::~QgsGeometryCheck ( )

virtualdefault

Member Function Documentation

◆ allLayerFeatureIds()

QMap< QString, QgsFeatureIds > QgsGeometryCheck::allLayerFeatureIds ( const QMap< QString, QgsFeaturePool *> & featurePools ) const

protected

Returns all layers and feature ids.

Note: Not available in Python bindings

Since: QGIS 3.4

Definition at line 59 of file qgsgeometrycheck.cpp.

◆ checkType()

virtual CheckType QgsGeometryCheck::checkType ( ) const

pure virtual

◆ collectErrors()

virtual void QgsGeometryCheck::collectErrors	(	const QMap< QString, QgsFeaturePool *> &	featurePools,
		QList< QgsGeometryCheckError *> &	errors,
		QStringList &	messages,
		QgsFeedback *	feedback,
		const LayerFeatureIds &	ids = `QgsGeometryCheck::LayerFeatureIds()`
	)		const

pure virtual

The main worker method.

Check all features available from featurePools and write errors found to errors. Other status messages can be written to messages. Progress should be reported to feedback. Only features and layers listed in ids should be checked.

Since: QGIS 3.4

Implemented in QgsSingleGeometryCheck, QgsGeometryOverlapCheck, QgsGeometryGapCheck, QgsGeometryMissingVertexCheck, QgsGeometryDuplicateCheck, QgsGeometryContainedCheck, QgsGeometryAngleCheck, QgsGeometryAreaCheck, QgsGeometryFollowBoundariesCheck, QgsGeometryLineLayerIntersectionCheck, QgsGeometrySegmentLengthCheck, QgsGeometryDangleCheck, QgsGeometryLineIntersectionCheck, QgsGeometryPointCoveredByLineCheck, QgsGeometryPointInPolygonCheck, QgsGeometryDegeneratePolygonCheck, QgsGeometryDuplicateNodesCheck, and QgsGeometryHoleCheck.

◆ compatibleGeometryTypes()

virtual QList<QgsWkbTypes::GeometryType> QgsGeometryCheck::compatibleGeometryTypes ( ) const

pure virtual

◆ configurationValue()

template<class T >

T QgsGeometryCheck::configurationValue	(	const QString &	name,
		const QVariant &	defaultValue = `QVariant()`
	)

inline

Returns the configuration value with the name, saved in the QGIS settings for this geometry check.

If no configuration could be found, defaultValue is returned.

Definition at line 270 of file qgsgeometrycheck.h.

◆ context()

const QgsGeometryCheckContext* QgsGeometryCheck::context ( ) const

inline

Returns the context.

Since: QGIS 3.4

Definition at line 347 of file qgsgeometrycheck.h.

◆ deleteFeatureGeometryPart()

void QgsGeometryCheck::deleteFeatureGeometryPart	(	const QMap< QString, QgsFeaturePool *> &	featurePools,
		const QString &	layerId,
		QgsFeature &	feature,
		int	partIdx,
		Changes &	changes
	)		const

protected

Deletes a part of a feature geometry.

Note: Not available in Python bindings

Since: QGIS 3.4

Definition at line 92 of file qgsgeometrycheck.cpp.

◆ deleteFeatureGeometryRing()

void QgsGeometryCheck::deleteFeatureGeometryRing	(	const QMap< QString, QgsFeaturePool *> &	featurePools,
		const QString &	layerId,
		QgsFeature &	feature,
		int	partIdx,
		int	ringIdx,
		Changes &	changes
	)		const

protected

Deletes a ring in a feature geometry.

Note: Not available in Python bindings

Since: QGIS 3.4

Definition at line 119 of file qgsgeometrycheck.cpp.

◆ description()

virtual QString QgsGeometryCheck::description ( ) const

pure virtual

◆ fixError()

void QgsGeometryCheck::fixError	(	const QMap< QString, QgsFeaturePool *> &	featurePools,
		QgsGeometryCheckError *	error,
		int	method,
		const QMap< QString, int > &	mergeAttributeIndices,
		QgsGeometryCheck::Changes &	changes
	)		const

virtual

Fixes the error error with the specified method.

Is executed on the main thread.

Since: QGIS 3.4

Reimplemented in QgsGeometryOverlapCheck, QgsGeometryGapCheck, QgsGeometryMissingVertexCheck, QgsGeometryDuplicateCheck, QgsGeometrySelfIntersectionCheck, QgsGeometryContainedCheck, QgsGeometryTypeCheck, QgsGeometryAngleCheck, QgsGeometryAreaCheck, QgsGeometryFollowBoundariesCheck, QgsGeometryLineLayerIntersectionCheck, QgsGeometrySegmentLengthCheck, QgsGeometryLineIntersectionCheck, QgsGeometryMultipartCheck, QgsGeometryPointCoveredByLineCheck, QgsGeometryPointInPolygonCheck, QgsGeometryDegeneratePolygonCheck, QgsGeometryDuplicateNodesCheck, QgsGeometryHoleCheck, QgsGeometrySelfContactCheck, and QgsGeometryDangleCheck.

Definition at line 50 of file qgsgeometrycheck.cpp.

◆ flags()

QgsGeometryCheck::Flags QgsGeometryCheck::flags ( ) const

virtual

Flags for this geometry check.

Reimplemented in QgsGeometryOverlapCheck, QgsGeometryGapCheck, QgsGeometryMissingVertexCheck, and QgsGeometrySelfIntersectionCheck.

Definition at line 45 of file qgsgeometrycheck.cpp.

◆ id()

virtual QString QgsGeometryCheck::id ( ) const

pure virtual

◆ isCompatible()

bool QgsGeometryCheck::isCompatible ( QgsVectorLayer * layer ) const

virtual

Returns if this geometry check is compatible with layer.

By default it checks for the geometry type in compatibleGeometryTypes().

Since: QGIS 3.4

Definition at line 40 of file qgsgeometrycheck.cpp.

◆ prepare()

void QgsGeometryCheck::prepare	(	const QgsGeometryCheckContext *	context,
		const QVariantMap &	configuration
	)

virtual

Will be run in the main thread before collectErrors is called (which may be run from a background thread).

Since: QGIS 3.10

Reimplemented in QgsGeometryGapCheck.

Definition at line 34 of file qgsgeometrycheck.cpp.

◆ replaceFeatureGeometryPart()

void QgsGeometryCheck::replaceFeatureGeometryPart	(	const QMap< QString, QgsFeaturePool *> &	featurePools,
		const QString &	layerId,
		QgsFeature &	feature,
		int	partIdx,
		QgsAbstractGeometry *	newPartGeom,
		Changes &	changes
	)		const

protected

Replaces a part in a feature geometry.

Note: Not available in Python bindings

Since: QGIS 3.4

Definition at line 69 of file qgsgeometrycheck.cpp.

◆ resolutionMethods()

virtual QStringList QgsGeometryCheck::resolutionMethods ( ) const

pure virtual

Returns a list of descriptions for available resolutions for errors.

The index will be passed as method to

See also: fixError().

Since: QGIS 3.4

Implemented in QgsGeometryOverlapCheck, QgsGeometryGapCheck, QgsGeometryMissingVertexCheck, QgsGeometryDuplicateCheck, QgsGeometrySelfIntersectionCheck, QgsGeometryContainedCheck, QgsGeometryIsValidCheck, QgsGeometryTypeCheck, QgsGeometryAngleCheck, QgsGeometryAreaCheck, QgsGeometryFollowBoundariesCheck, QgsGeometryDegeneratePolygonCheck, QgsGeometryLineLayerIntersectionCheck, QgsGeometrySegmentLengthCheck, QgsGeometryLineIntersectionCheck, QgsGeometryMultipartCheck, QgsGeometryPointCoveredByLineCheck, QgsGeometryPointInPolygonCheck, QgsGeometryDangleCheck, QgsGeometryDuplicateNodesCheck, QgsGeometryHoleCheck, and QgsGeometrySelfContactCheck.

◆ scaleFactor()

double QgsGeometryCheck::scaleFactor ( const QPointer< QgsVectorLayer > & layer ) const

protected

Determines the scale factor of a layer to the map coordinate reference system.

Note: Not available in Python bindings

Since: QGIS 3.4

Definition at line 148 of file qgsgeometrycheck.cpp.

Member Data Documentation

◆ mConfiguration

QVariantMap QgsGeometryCheck::mConfiguration

protected

Definition at line 384 of file qgsgeometrycheck.h.

◆ mContext

const QgsGeometryCheckContext* QgsGeometryCheck::mContext

protected

Definition at line 383 of file qgsgeometrycheck.h.

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

/build/qgis-3.10.0+15buster/src/analysis/vector/geometry_checker/qgsgeometrycheck.h
/build/qgis-3.10.0+15buster/src/analysis/vector/geometry_checker/qgsgeometrycheck.cpp

Classes

Public Types

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Writing the check

Creating a geometry check factory

Registering the geometry check

Member Typedef Documentation

◆ Changes

Member Enumeration Documentation

◆ ChangeType

◆ ChangeWhat

◆ CheckType

◆ Flag

Constructor & Destructor Documentation

◆ QgsGeometryCheck()

◆ ~QgsGeometryCheck()

Member Function Documentation

◆ allLayerFeatureIds()

◆ checkType()

◆ collectErrors()

◆ compatibleGeometryTypes()

◆ configurationValue()

◆ context()

◆ deleteFeatureGeometryPart()

◆ deleteFeatureGeometryRing()

◆ description()

◆ fixError()

◆ flags()

◆ id()

◆ isCompatible()

◆ prepare()

◆ replaceFeatureGeometryPart()

◆ resolutionMethods()

◆ scaleFactor()

Member Data Documentation

◆ mConfiguration

◆ mContext