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 null, 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 null 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 null, it will index only that area
`setRenderContext`	Configure render context - if not null, 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 null 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 null 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 null, it will index only that area

New in version 2.14.

setRenderContext(self, context: QgsRenderContext)¶: Configure render context - if not null, 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.