The class defines interface for querying point location: More...

#include <qgspointlocator.h>

Inheritance diagram for QgsPointLocator:

Classes
struct	Match

struct	MatchFilter
	Interface that allows rejection of some matches in intersection queries (e.g. More...

Public Types
typedef class QList< QgsPointLocator::Match >	MatchList

enum	Type { Invalid = 0 , Vertex = 1 << 0 , Edge = 1 << 1 , Area = 1 << 2 , Centroid = 1 << 3 , MiddleOfSegment = 1 << 4 , LineEndpoint = 1 << 5 , All = Vertex \| Edge \| Area \| Centroid \| MiddleOfSegment }
	The type of a snap result or the filter type for a snap request. More...

typedef QFlags< Type >	Types

Signals
void	initFinished (bool ok)
	Emitted whenever index has been built and initialization is finished.

Public Member Functions
	QgsPointLocator (QgsVectorLayer layer, const QgsCoordinateReferenceSystem &destinationCrs=QgsCoordinateReferenceSystem(), const QgsCoordinateTransformContext &transformContext=QgsCoordinateTransformContext(), const QgsRectangle extent=nullptr)
	Construct point locator for a layer.

	~QgsPointLocator () override

int	cachedGeometryCount () const
	Returns how many geometries are cached in the index.

QgsCoordinateReferenceSystem	destinationCrs () const
	Gets destination CRS - may be an invalid QgsCoordinateReferenceSystem if not doing OTF reprojection.

MatchList	edgesInRect (const QgsPointXY &point, double tolerance, QgsPointLocator::MatchFilter *filter=nullptr, bool relaxed=false)
	Override of edgesInRect that construct rectangle from a center point and tolerance This method is either blocking or non blocking according to relaxed parameter passed.

MatchList	edgesInRect (const QgsRectangle &rect, QgsPointLocator::MatchFilter *filter=nullptr, bool relaxed=false)
	Find edges within a specified rectangle Optional filter may discard unwanted matches.

const QgsRectangle *	extent () const
	Gets extent of the area point locator covers - if `nullptr` then it caches the whole layer.

bool	hasIndex () const
	Indicate whether the data have been already indexed.

bool	init (int maxFeaturesToIndex=-1, bool relaxed=false)
	Prepare the index for queries.

bool	isIndexing () const
	Returns `true` if the point locator is currently indexing the data.

QgsVectorLayer *	layer () const
	Gets associated layer.

Match	nearestArea (const QgsPointXY &point, double tolerance, QgsPointLocator::MatchFilter *filter=nullptr, bool relaxed=false)
	Find nearest area to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.

Match	nearestCentroid (const QgsPointXY &point, double tolerance, QgsPointLocator::MatchFilter *filter=nullptr, bool relaxed=false)
	Find nearest centroid to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.

Match	nearestEdge (const QgsPointXY &point, double tolerance, QgsPointLocator::MatchFilter *filter=nullptr, bool relaxed=false)
	Find nearest edge to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.

Match	nearestLineEndpoints (const QgsPointXY &point, double tolerance, QgsPointLocator::MatchFilter *filter=nullptr, bool relaxed=false)
	Find nearest line endpoint (start or end vertex) to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.

Match	nearestMiddleOfSegment (const QgsPointXY &point, double tolerance, QgsPointLocator::MatchFilter *filter=nullptr, bool relaxed=false)
	Find nearest middle of segment to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.

Match	nearestVertex (const QgsPointXY &point, double tolerance, QgsPointLocator::MatchFilter *filter=nullptr, bool relaxed=false)
	Find nearest vertex to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.

MatchList	pointInPolygon (const QgsPointXY &point, bool relaxed=false, QgsPointLocator::MatchFilter *filter=nullptr)
	Find out if the point is in any polygons.

void	setExtent (const QgsRectangle *extent)
	Configure extent - if not `nullptr`, it will index only that area.

void	setRenderContext (const QgsRenderContext *context)
	Configure render context - if not `nullptr`, it will use to index only visible feature.

MatchList	verticesInRect (const QgsPointXY &point, double tolerance, QgsPointLocator::MatchFilter *filter=nullptr, bool relaxed=false)
	Override of verticesInRect that construct rectangle from a center point and tolerance This method is either blocking or non blocking according to relaxed parameter passed.

MatchList	verticesInRect (const QgsRectangle &rect, QgsPointLocator::MatchFilter *filter=nullptr, bool relaxed=false)
	Find vertices within a specified rectangle This method is either blocking or non blocking according to relaxed parameter passed Optional filter may discard unwanted matches.

void	waitForIndexingFinished ()
	If the point locator has been initialized relaxedly and is currently indexing, this methods waits for the indexing to be finished.

Protected Slots
void	destroyIndex ()

Protected Member Functions
bool	rebuildIndex (int maxFeaturesToIndex=-1)

Friends
class	QgsPointLocator_VisitorArea

class	QgsPointLocator_VisitorCentroidsInRect

class	QgsPointLocator_VisitorEdgesInRect

class	QgsPointLocator_VisitorMiddlesInRect

class	QgsPointLocator_VisitorNearestCentroid

class	QgsPointLocator_VisitorNearestEdge

class	QgsPointLocator_VisitorNearestLineEndpoint

class	QgsPointLocator_VisitorNearestMiddleOfSegment

class	QgsPointLocator_VisitorNearestVertex

class	QgsPointLocator_VisitorVerticesInRect

class	QgsPointLocatorInitTask

class	TestQgsPointLocator

Detailed Description

The class defines interface for querying point location:

query nearest vertices / edges to a point
query vertices / edges in rectangle
query areas covering a point

Works with one layer.

Definition at line 100 of file qgspointlocator.h.

Member Typedef Documentation

◆ MatchList

typedef class QList< QgsPointLocator::Match > QgsPointLocator::MatchList

Definition at line 343 of file qgspointlocator.h.

◆ Types

typedef QFlags< Type > QgsPointLocator::Types

Definition at line 162 of file qgspointlocator.h.

Member Enumeration Documentation

◆ Type

enum QgsPointLocator::Type

The type of a snap result or the filter type for a snap request.

Enumerator
Invalid	Invalid.
Vertex	Snapped to a vertex. Can be a vertex of the geometry or an intersection.
Edge	Snapped to an edge.
Area	Snapped to an area.
Centroid	Snapped to a centroid.
MiddleOfSegment	Snapped to the middle of a segment.
LineEndpoint	Start or end points of lines only. Since QGIS 3.20
All	Combination of all types. Note LineEndpoint is not included as endpoints made redundant by the presence of the Vertex flag.

Definition at line 150 of file qgspointlocator.h.

Constructor & Destructor Documentation

◆ QgsPointLocator()

QgsPointLocator::QgsPointLocator	(	QgsVectorLayer *	layer,
		const QgsCoordinateReferenceSystem &	destinationCrs = `QgsCoordinateReferenceSystem()`,
		const QgsCoordinateTransformContext &	transformContext = `QgsCoordinateTransformContext()`,
		const QgsRectangle *	extent = `nullptr`
	)

explicit

Construct point locator for a layer.

If a valid QgsCoordinateReferenceSystem is passed for destinationCrs then the locator will do the searches on data reprojected to the given CRS. For accurate reprojection it is important to set the correct transformContext if a destinationCrs is specified. This is usually taken from the current QgsProject::transformContext().

If extent is not nullptr, the locator will index only a subset of the layer which falls within that extent.

Definition at line 876 of file qgspointlocator.cpp.

◆ ~QgsPointLocator()

QgsPointLocator::~QgsPointLocator ( )

override

Definition at line 896 of file qgspointlocator.cpp.

Member Function Documentation

◆ cachedGeometryCount()

int QgsPointLocator::cachedGeometryCount ( ) const

inline

Returns how many geometries are cached in the index.

Definition at line 452 of file qgspointlocator.h.

◆ destinationCrs()

QgsCoordinateReferenceSystem QgsPointLocator::destinationCrs ( ) const

Gets destination CRS - may be an invalid QgsCoordinateReferenceSystem if not doing OTF reprojection.

Definition at line 906 of file qgspointlocator.cpp.

◆ destroyIndex

void QgsPointLocator::destroyIndex ( )

protectedslot

Definition at line 1184 of file qgspointlocator.cpp.

◆ edgesInRect() [1/2]

QgsPointLocator::MatchList QgsPointLocator::edgesInRect	(	const QgsPointXY &	point,
		double	tolerance,
		QgsPointLocator::MatchFilter *	filter = `nullptr`,
		bool	relaxed = `false`
	)

Override of edgesInRect that construct rectangle from a center point and tolerance This method is either blocking or non blocking according to relaxed parameter passed.

Definition at line 1453 of file qgspointlocator.cpp.

◆ edgesInRect() [2/2]

QgsPointLocator::MatchList QgsPointLocator::edgesInRect	(	const QgsRectangle &	rect,
		QgsPointLocator::MatchFilter *	filter = `nullptr`,
		bool	relaxed = `false`
	)

Find edges within a specified rectangle Optional filter may discard unwanted matches.

This method is either blocking or non blocking according to relaxed parameter passed

Definition at line 1437 of file qgspointlocator.cpp.

◆ extent()

const QgsRectangle * QgsPointLocator::extent ( ) const

inline

Gets extent of the area point locator covers - if nullptr then it caches the whole layer.

Definition at line 134 of file qgspointlocator.h.

◆ hasIndex()

bool QgsPointLocator::hasIndex ( ) const

Indicate whether the data have been already indexed.

Definition at line 1019 of file qgspointlocator.cpp.

◆ init()

bool QgsPointLocator::init	(	int	maxFeaturesToIndex = `-1`,
		bool	relaxed = `false`
	)

Prepare the index for queries.

Does nothing if the index already exists. If the number of features is greater than the value of maxFeaturesToIndex, creation of index is stopped to make sure we do not run out of memory. If maxFeaturesToIndex is -1, no limits are used.

This method is either blocking or non blocking according to relaxed parameter passed in the constructor. if true, index building will be done in another thread and init() method returns immediately. initFinished() signal will be emitted once the initialization is over.

Returns false if the creation of index is blocking and has been prematurely stopped due to the limit of features, otherwise true

See also: QgsPointLocator()

Definition at line 969 of file qgspointlocator.cpp.

◆ initFinished

void QgsPointLocator::initFinished ( bool ok )

signal

Emitted whenever index has been built and initialization is finished.

Parameters

ok	`false` if the creation of index has been prematurely stopped due to the limit of features, otherwise `true`

◆ isIndexing()

bool QgsPointLocator::isIndexing ( ) const

inline

Returns true if the point locator is currently indexing the data.

This method is useful if constructor parameter relaxed is true

See also: QgsPointLocator()

Definition at line 460 of file qgspointlocator.h.

◆ layer()

QgsVectorLayer * QgsPointLocator::layer ( ) const

inline

Gets associated layer.

Definition at line 124 of file qgspointlocator.h.

◆ nearestArea()

QgsPointLocator::Match QgsPointLocator::nearestArea	(	const QgsPointXY &	point,
		double	tolerance,
		QgsPointLocator::MatchFilter *	filter = `nullptr`,
		bool	relaxed = `false`
	)

Find nearest area to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.

This will first perform a pointInPolygon and return first result. If no match is found and tolerance is not 0, it will return nearestEdge. This method is either blocking or non blocking according to relaxed parameter passed

Definition at line 1407 of file qgspointlocator.cpp.

◆ nearestCentroid()

QgsPointLocator::Match QgsPointLocator::nearestCentroid	(	const QgsPointXY &	point,
		double	tolerance,
		QgsPointLocator::MatchFilter *	filter = `nullptr`,
		bool	relaxed = `false`
	)

Find nearest centroid to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.

This method is either blocking or non blocking according to relaxed parameter passed

Since: QGIS 3.12

Definition at line 1344 of file qgspointlocator.cpp.

◆ nearestEdge()

QgsPointLocator::Match QgsPointLocator::nearestEdge	(	const QgsPointXY &	point,
		double	tolerance,
		QgsPointLocator::MatchFilter *	filter = `nullptr`,
		bool	relaxed = `false`
	)

Find nearest edge to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.

This method is either blocking or non blocking according to relaxed parameter passed

Definition at line 1389 of file qgspointlocator.cpp.

◆ nearestLineEndpoints()

QgsPointLocator::Match QgsPointLocator::nearestLineEndpoints	(	const QgsPointXY &	point,
		double	tolerance,
		QgsPointLocator::MatchFilter *	filter = `nullptr`,
		bool	relaxed = `false`
	)

Find nearest line endpoint (start or end vertex) to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.

This method is either blocking or non blocking according to relaxed parameter passed

Since: QGIS 3.20

Definition at line 1374 of file qgspointlocator.cpp.

◆ nearestMiddleOfSegment()

QgsPointLocator::Match QgsPointLocator::nearestMiddleOfSegment	(	const QgsPointXY &	point,
		double	tolerance,
		QgsPointLocator::MatchFilter *	filter = `nullptr`,
		bool	relaxed = `false`
	)

Find nearest middle of segment to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.

This method is either blocking or non blocking according to relaxed parameter passed

Since: QGIS 3.12

Definition at line 1359 of file qgspointlocator.cpp.

◆ nearestVertex()

QgsPointLocator::Match QgsPointLocator::nearestVertex	(	const QgsPointXY &	point,
		double	tolerance,
		QgsPointLocator::MatchFilter *	filter = `nullptr`,
		bool	relaxed = `false`
	)

Find nearest vertex to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.

This method is either blocking or non blocking according to relaxed parameter passed

Definition at line 1330 of file qgspointlocator.cpp.

◆ pointInPolygon()

QgsPointLocator::MatchList QgsPointLocator::pointInPolygon	(	const QgsPointXY &	point,
		bool	relaxed = `false`,
		QgsPointLocator::MatchFilter *	filter = `nullptr`
	)

Find out if the point is in any polygons.

Parameters

point	The point to check polygons against, in map coordinates
relaxed	`true` if index build has to be non blocking
filter	since QGIS 3.36, Optional filter may discard unwanted matches.

Note: Parameters filter and relaxed are in reversed order compared to the rest of MatchList returning methods.

Definition at line 1477 of file qgspointlocator.cpp.

◆ rebuildIndex()

bool QgsPointLocator::rebuildIndex ( int maxFeaturesToIndex = -1 )

protected

Definition at line 1044 of file qgspointlocator.cpp.

◆ setExtent()

void QgsPointLocator::setExtent ( const QgsRectangle * extent )

Configure extent - if not nullptr, it will index only that area.

Definition at line 911 of file qgspointlocator.cpp.

◆ setRenderContext()

void QgsPointLocator::setRenderContext ( const QgsRenderContext * context )

Configure render context - if not nullptr, it will use to index only visible feature.

Since: QGIS 3.2

Definition at line 922 of file qgspointlocator.cpp.

◆ verticesInRect() [1/2]

QgsPointLocator::MatchList QgsPointLocator::verticesInRect	(	const QgsPointXY &	point,
		double	tolerance,
		QgsPointLocator::MatchFilter *	filter = `nullptr`,
		bool	relaxed = `false`
	)

Override of verticesInRect that construct rectangle from a center point and tolerance This method is either blocking or non blocking according to relaxed parameter passed.

Since: QGIS 3.6

Definition at line 1471 of file qgspointlocator.cpp.

◆ verticesInRect() [2/2]

QgsPointLocator::MatchList QgsPointLocator::verticesInRect	(	const QgsRectangle &	rect,
		QgsPointLocator::MatchFilter *	filter = `nullptr`,
		bool	relaxed = `false`
	)

Find vertices within a specified rectangle This method is either blocking or non blocking according to relaxed parameter passed Optional filter may discard unwanted matches.

Since: QGIS 3.6

Definition at line 1459 of file qgspointlocator.cpp.

◆ waitForIndexingFinished()

void QgsPointLocator::waitForIndexingFinished ( )

If the point locator has been initialized relaxedly and is currently indexing, this methods waits for the indexing to be finished.

Definition at line 1008 of file qgspointlocator.cpp.

Friends And Related Symbol Documentation

◆ QgsPointLocator_VisitorArea

friend class QgsPointLocator_VisitorArea

friend

Definition at line 526 of file qgspointlocator.h.

◆ QgsPointLocator_VisitorCentroidsInRect

friend class QgsPointLocator_VisitorCentroidsInRect

friend

Definition at line 531 of file qgspointlocator.h.

◆ QgsPointLocator_VisitorEdgesInRect

friend class QgsPointLocator_VisitorEdgesInRect

friend

Definition at line 527 of file qgspointlocator.h.

◆ QgsPointLocator_VisitorMiddlesInRect

friend class QgsPointLocator_VisitorMiddlesInRect

friend

Definition at line 532 of file qgspointlocator.h.

◆ QgsPointLocator_VisitorNearestCentroid

friend class QgsPointLocator_VisitorNearestCentroid

friend

Definition at line 523 of file qgspointlocator.h.

◆ QgsPointLocator_VisitorNearestEdge

friend class QgsPointLocator_VisitorNearestEdge

friend

Definition at line 525 of file qgspointlocator.h.

◆ QgsPointLocator_VisitorNearestLineEndpoint

friend class QgsPointLocator_VisitorNearestLineEndpoint

friend

Definition at line 533 of file qgspointlocator.h.

◆ QgsPointLocator_VisitorNearestMiddleOfSegment

friend class QgsPointLocator_VisitorNearestMiddleOfSegment

friend

Definition at line 524 of file qgspointlocator.h.

◆ QgsPointLocator_VisitorNearestVertex

friend class QgsPointLocator_VisitorNearestVertex

friend

Definition at line 522 of file qgspointlocator.h.

◆ QgsPointLocator_VisitorVerticesInRect

friend class QgsPointLocator_VisitorVerticesInRect

friend

Definition at line 528 of file qgspointlocator.h.

◆ QgsPointLocatorInitTask

friend class QgsPointLocatorInitTask

friend

Definition at line 529 of file qgspointlocator.h.

◆ TestQgsPointLocator

friend class TestQgsPointLocator

friend

Definition at line 530 of file qgspointlocator.h.

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

/build/qgis-3.41.0+git20241119+45a0abf3bec+99sid/src/core/qgspointlocator.h
/build/qgis-3.41.0+git20241119+45a0abf3bec+99sid/src/core/qgspointlocator.cpp

Classes

Public Types

Signals

Public Member Functions

Protected Slots

Protected Member Functions

Friends

Detailed Description

Member Typedef Documentation

◆ MatchList

◆ Types

Member Enumeration Documentation

◆ Type

Constructor & Destructor Documentation

◆ QgsPointLocator()

◆ ~QgsPointLocator()

Member Function Documentation

◆ cachedGeometryCount()

◆ destinationCrs()

◆ destroyIndex

◆ edgesInRect() [1/2]

◆ edgesInRect() [2/2]

◆ extent()

◆ hasIndex()

◆ init()

◆ initFinished

◆ isIndexing()

◆ layer()

◆ nearestArea()

◆ nearestCentroid()

◆ nearestEdge()

◆ nearestLineEndpoints()

◆ nearestMiddleOfSegment()

◆ nearestVertex()

◆ pointInPolygon()

◆ rebuildIndex()

◆ setExtent()

◆ setRenderContext()

◆ verticesInRect() [1/2]

◆ verticesInRect() [2/2]

◆ waitForIndexingFinished()

Friends And Related Symbol Documentation

◆ QgsPointLocator_VisitorArea

◆ QgsPointLocator_VisitorCentroidsInRect

◆ QgsPointLocator_VisitorEdgesInRect

◆ QgsPointLocator_VisitorMiddlesInRect

◆ QgsPointLocator_VisitorNearestCentroid

◆ QgsPointLocator_VisitorNearestEdge

◆ QgsPointLocator_VisitorNearestLineEndpoint

◆ QgsPointLocator_VisitorNearestMiddleOfSegment

◆ QgsPointLocator_VisitorNearestVertex

◆ QgsPointLocator_VisitorVerticesInRect

◆ QgsPointLocatorInitTask

◆ TestQgsPointLocator