QgsPointLocator Class Reference

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

#include <qgspointlocator.h>

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

Public Types
typedef class QList< Match >	MatchList
enum	Type {   Invalid = 0, Vertex = 1, Edge = 2, Area = 4,   All = Vertex | Edge | Area }

Public Member Functions
	QgsPointLocator (QgsVectorLayer *layer, const QgsCoordinateReferenceSystem *destCRS=0, const QgsRectangle *extent=0)
	Construct point locator for a layer.
	~QgsPointLocator ()
MatchList	edgesInRect (const QgsRectangle &rect, MatchFilter *filter=0)
	Find edges within a specified recangle Optional filter may discard unwanted matches.
MatchList	edgesInRect (const QgsPoint &point, double tolerance, MatchFilter *filter=0)
	Override of edgesInRect that construct rectangle from a center point and tolerance.
bool	hasIndex () const
	Indicate whether the data have been already indexed.
bool	init (int maxFeaturesToIndex=-1)
	Prepare the index for queries.
Match	nearestEdge (const QgsPoint &point, double tolerance, MatchFilter *filter=0)
	Find nearest edges to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.
Match	nearestVertex (const QgsPoint &point, double tolerance, MatchFilter *filter=0)
	Find nearest vertex to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.
MatchList	pointInPolygon (const QgsPoint &point)
	find out if the point is in any polygons

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

Friends
class	QgsPointLocator_VisitorArea
class	QgsPointLocator_VisitorEdgesInRect
class	QgsPointLocator_VisitorNearestEdge
class	QgsPointLocator_VisitorNearestVertex

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.

Note

added in 2.8

Definition at line 48 of file qgspointlocator.h.

Member Typedef Documentation

typedef class QList< Match > QgsPointLocator::MatchList

Definition at line 126 of file qgspointlocator.h.

Member Enumeration Documentation

enum QgsPointLocator::Type

Enumerator:

Invalid
Vertex
Edge
Area
All

Definition at line 60 of file qgspointlocator.h.

Constructor & Destructor Documentation

QgsPointLocator::QgsPointLocator ( QgsVectorLayer *  layer, const QgsCoordinateReferenceSystem *  destCRS = 0, const QgsRectangle *  extent = 0  )

explicit

Construct point locator for a layer.

• destCRS if not null, will do the searches on data reprojected to the given CRS
• extent if not null, will index only a subset of the layer

Definition at line 571 of file qgspointlocator.cpp.

QgsPointLocator::~QgsPointLocator

(

)

Definition at line 597 of file qgspointlocator.cpp.

Member Function Documentation

void QgsPointLocator::destroyIndex ( )

protected

Definition at line 696 of file qgspointlocator.cpp.

QgsPointLocator::MatchList QgsPointLocator::edgesInRect	(	const QgsRectangle &	rect,
		QgsPointLocator::MatchFilter *	filter = 0
	)

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

Definition at line 796 of file qgspointlocator.cpp.

QgsPointLocator::MatchList QgsPointLocator::edgesInRect	(	const QgsPoint &	point,
		double	tolerance,
		QgsPointLocator::MatchFilter *	filter = 0
	)

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

Definition at line 812 of file qgspointlocator.cpp.

bool QgsPointLocator::hasIndex

(

)

const

Indicate whether the data have been already indexed.

Definition at line 611 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 606 of file qgspointlocator.cpp.

QgsPointLocator::Match QgsPointLocator::nearestEdge	(	const QgsPoint &	point,
		double	tolerance,
		MatchFilter *	filter = 0
	)

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

Definition at line 778 of file qgspointlocator.cpp.

QgsPointLocator::Match QgsPointLocator::nearestVertex	(	const QgsPoint &	point,
		double	tolerance,
		MatchFilter *	filter = 0
	)

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

Definition at line 760 of file qgspointlocator.cpp.

QgsPointLocator::MatchList QgsPointLocator::pointInPolygon

(

const QgsPoint &

point

)

find out if the point is in any polygons

Definition at line 819 of file qgspointlocator.cpp.

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

protected

Definition at line 618 of file qgspointlocator.cpp.

Friends And Related Function Documentation

friend class QgsPointLocator_VisitorArea

friend

Definition at line 183 of file qgspointlocator.h.

friend class QgsPointLocator_VisitorEdgesInRect

friend

Definition at line 184 of file qgspointlocator.h.

friend class QgsPointLocator_VisitorNearestEdge

friend

Definition at line 182 of file qgspointlocator.h.

friend class QgsPointLocator_VisitorNearestVertex

friend

Definition at line 181 of file qgspointlocator.h.

---

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

• /tmp/buildd/qgis-2.8.2+12wheezy/src/core/qgspointlocator.h
• /tmp/buildd/qgis-2.8.2+12wheezy/src/core/qgspointlocator.cpp