Class: QgsPointLocator

class qgis.core.QgsPointLocator(layer: QgsVectorLayer, destinationCrs: QgsCoordinateReferenceSystem = QgsCoordinateReferenceSystem(), transformContext: QgsCoordinateTransformContext = QgsCoordinateTransformContext(), extent: QgsRectangle = None)

Bases: PyQt5.QtCore.QObject

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 None, the locator will index only a subset of the layer which falls within that extent.

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.

New in version 2.8: Enums

Methods

cachedGeometryCount Returns how many geometries are cached in the index
childEvent
connectNotify
customEvent
destinationCrs Gets destination CRS - may be an invalid QgsCoordinateReferenceSystem if not doing OTF reprojection
destroyIndex
disconnectNotify
edgesInRect Find edges within a specified recangle Optional filter may discard unwanted matches.
extent Gets extent of the area point locator covers - if None then it caches the whole layer
hasIndex Indicate whether the data have been already indexed
init Prepare the index for queries.
isSignalConnected
layer Gets associated layer
nearestArea Find nearest area to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.
nearestEdge Find nearest edge to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.
nearestVertex Find nearest vertex to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.
pointInPolygon find out if the point is in any polygons
rebuildIndex
receivers
sender
senderSignalIndex
setExtent Configure extent - if not None, it will index only that area
setRenderContext Configure render context - if not None, it will use to index only visible feature
timerEvent
verticesInRect Find vertices within a specified recangle Optional filter may discard unwanted matches.

Signals

Attributes

All
Area
Edge
Invalid
Vertex
All = 7
Area = 4
Edge = 2
Invalid = 0
class Match

Bases: sip.wrapper

construct invalid match

QgsPointLocator.Match(t: QgsPointLocator.Type, vl: QgsVectorLayer, fid: int, dist: float, pt: QgsPointXY, vertexIndex: int = 0, edgePoints: QgsPointXY = None)

QgsPointLocator.Match(QgsPointLocator.Match)

distance(self) → float

for vertex / edge match units depending on what class returns it (geom.cache: layer units, map canvas snapper: dest crs units)

edgePoints(self) → Tuple[QgsPointXY, QgsPointXY]

Only for a valid edge match - obtain endpoints of the edge

featureId(self) → int

The id of the feature to which the snapped geometry belongs.

hasArea(self) → bool
hasEdge(self) → bool
hasVertex(self) → bool
isValid(self) → bool
layer(self) → QgsVectorLayer

The vector layer where the snap occurred. Will be None if the snap happened on an intersection.

point(self) → QgsPointXY

for vertex / edge match coords depending on what class returns it (geom.cache: layer coords, map canvas snapper: dest coords)

type(self) → QgsPointLocator.Type
vertexIndex(self) → int

for vertex / edge match (first vertex of the edge)

class MatchFilter

Bases: sip.wrapper

QgsPointLocator.MatchFilter(QgsPointLocator.MatchFilter)

acceptMatch(self, match: QgsPointLocator.Match) → bool
class Type

Bases: int

class Types

Bases: sip.wrapper

QgsPointLocator.Types(Union[QgsPointLocator.Types, QgsPointLocator.Type]) QgsPointLocator.Types(QgsPointLocator.Types)

Vertex = 1
cachedGeometryCount(self) → int

Returns how many geometries are cached in the index

New in version 2.14.

childEvent()
connectNotify()
customEvent()
destinationCrs(self) → QgsCoordinateReferenceSystem

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

New in version 2.14.

destroyIndex(self)
disconnectNotify()
edgesInRect(self, rect: QgsRectangle, filter: QgsPointLocator.MatchFilter = None) → object

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

edgesInRect(self, point: QgsPointXY, tolerance: float, filter: QgsPointLocator.MatchFilter = None) -> object Override of edgesInRect that construct rectangle from a center point and tolerance

extent(self) → QgsRectangle

Gets extent of the area point locator covers - if None then it caches the whole layer

New in version 2.14.

hasIndex(self) → bool

Indicate whether the data have been already indexed

init(self, maxFeaturesToIndex: int = -1) → bool

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

isSignalConnected()
layer(self) → QgsVectorLayer

Gets associated layer

New in version 2.14.

nearestArea(self, point: QgsPointXY, tolerance: float, filter: QgsPointLocator.MatchFilter = None) → QgsPointLocator.Match

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.

New in version 3.0.

nearestEdge(self, point: QgsPointXY, tolerance: float, filter: QgsPointLocator.MatchFilter = None) → QgsPointLocator.Match

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

nearestVertex(self, point: QgsPointXY, tolerance: float, filter: QgsPointLocator.MatchFilter = None) → QgsPointLocator.Match

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

pointInPolygon(self, point: QgsPointXY) → object

find out if the point is in any polygons

rebuildIndex(self, maxFeaturesToIndex: int = -1) → bool
receivers()
sender()
senderSignalIndex()
setExtent(self, extent: QgsRectangle)

Configure extent - if not None, it will index only that area

New in version 2.14.

setRenderContext(self, context: QgsRenderContext)

Configure render context - if not None, it will use to index only visible feature

New in version 3.2.

timerEvent()
verticesInRect(self, rect: QgsRectangle, filter: QgsPointLocator.MatchFilter = None) → object

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

New in version 3.6.

verticesInRect(self, point: QgsPointXY, tolerance: float, filter: QgsPointLocator.MatchFilter = None) -> object Override of verticesInRect that construct rectangle from a center point and tolerance

New in version 3.6.