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, Edge = 2, Area = 4, All = Vertex \| Edge \| Area }
	The type of a snap result or the filter type for a snap request. More...

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

	~QgsPointLocator () override

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

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

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

MatchList	edgesInRect (const QgsPointXY &point, double tolerance, QgsPointLocator::MatchFilter *filter=nullptr)
	Override of edgesInRect that construct rectangle from a center point and tolerance. More...

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

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

bool	init (int maxFeaturesToIndex=-1)
	Prepare the index for queries. More...

QgsVectorLayer *	layer () const
	Gets associated layer. More...

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

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

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

MatchList	pointInPolygon (const QgsPointXY &point)
	find out if the point is in any polygons More...

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

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

MatchList	verticesInRect (const QgsRectangle &rect, QgsPointLocator::MatchFilter *filter=nullptr)
	Find vertices within a specified recangle Optional filter may discard unwanted matches. More...

MatchList	verticesInRect (const QgsPointXY &point, double tolerance, QgsPointLocator::MatchFilter *filter=nullptr)
	Override of verticesInRect that construct rectangle from a center point and tolerance. More...

Protected Slots
void	destroyIndex ()

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

Friends
class	QgsPointLocator_VisitorArea

class	QgsPointLocator_VisitorEdgesInRect

class	QgsPointLocator_VisitorNearestEdge

class	QgsPointLocator_VisitorNearestVertex

class	QgsPointLocator_VisitorVerticesInRect

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.

Since: QGIS 2.8

Definition at line 55 of file qgspointlocator.h.

Member Typedef Documentation

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

Definition at line 212 of file qgspointlocator.h.

Member Enumeration Documentation

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.
All	Combination of vertex, edge and area.

Definition at line 109 of file qgspointlocator.h.

Constructor & Destructor Documentation

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 null, the locator will index only a subset of the layer which falls within that extent.

Definition at line 524 of file qgspointlocator.cpp.

QgsPointLocator::~QgsPointLocator ( )

override

Definition at line 544 of file qgspointlocator.cpp.

Member Function Documentation

int QgsPointLocator::cachedGeometryCount ( ) const

inline

Returns how many geometries are cached in the index.

Since: QGIS 2.14

Definition at line 282 of file qgspointlocator.h.

QgsCoordinateReferenceSystem QgsPointLocator::destinationCrs ( ) const

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

Since: QGIS 2.14

Definition at line 549 of file qgspointlocator.cpp.

void QgsPointLocator::destroyIndex ( )

protectedslot

Definition at line 716 of file qgspointlocator.cpp.

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

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

Definition at line 902 of file qgspointlocator.cpp.

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

Override of edgesInRect that construct rectangle from a center point and tolerance.

Definition at line 922 of file qgspointlocator.cpp.

const QgsRectangle* QgsPointLocator::extent ( ) const

inline

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

Since: QGIS 2.14

Definition at line 92 of file qgspointlocator.h.

bool QgsPointLocator::hasIndex ( ) const

Indicate whether the data have been already indexed.

Definition at line 582 of file qgspointlocator.cpp.

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

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

Definition at line 576 of file qgspointlocator.cpp.

QgsVectorLayer* QgsPointLocator::layer ( ) const

inline

Gets associated layer.

Since: QGIS 2.14

Definition at line 80 of file qgspointlocator.h.

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

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.

Since: QGIS 3.0

Definition at line 868 of file qgspointlocator.cpp.

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

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

Definition at line 846 of file qgspointlocator.cpp.

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

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

Definition at line 828 of file qgspointlocator.cpp.

QgsPointLocator::MatchList QgsPointLocator::pointInPolygon ( const QgsPointXY & point )

find out if the point is in any polygons

Definition at line 951 of file qgspointlocator.cpp.

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

protected

Definition at line 588 of file qgspointlocator.cpp.

void QgsPointLocator::setExtent ( const QgsRectangle * extent )

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

Since: QGIS 2.14

Definition at line 554 of file qgspointlocator.cpp.

void QgsPointLocator::setRenderContext ( const QgsRenderContext * context )

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

Since: QGIS 3.2

Definition at line 561 of file qgspointlocator.cpp.

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

Find vertices within a specified recangle Optional filter may discard unwanted matches.

Since: QGIS 3.6

Definition at line 928 of file qgspointlocator.cpp.

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