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.

Parameters
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)

Return type

float

edgePoints(self) → Tuple[QgsPointXY, QgsPointXY]

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

Return type

Tuple[QgsPointXY, QgsPointXY]

featureId(self) → int

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

Return type

int

hasArea(self) → bool
Return type

bool

hasEdge(self) → bool
Return type

bool

hasVertex(self) → bool
Return type

bool

interpolatedPoint(self) → QgsPoint

Convenient method to return a point on an edge with linear interpolation of the Z value.

New in version 3.10.

Return type

QgsPoint

isValid(self) → bool
Return type

bool

layer(self) → QgsVectorLayer

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

Return type

QgsVectorLayer

point(self) → QgsPointXY

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

Return type

QgsPointXY

type(self) → QgsPointLocator.Type
Return type

QgsPointLocator.Type

vertexIndex(self) → int

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

Return type

int

class MatchFilter

Bases: sip.wrapper

QgsPointLocator.MatchFilter(QgsPointLocator.MatchFilter)

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

match (QgsPointLocator.Match) –

Return type

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.

Return type

int

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

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

New in version 2.14.

Return type

QgsCoordinateReferenceSystem

destroyIndex(self)
disconnectNotify()
edgesInRect(self, rect: QgsRectangle, filter: QgsPointLocator.MatchFilter = None, relaxed: bool = False) → List[QgsPointLocator.Match]

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

edgesInRect(self, point: QgsPointXY, tolerance: float, filter: QgsPointLocator.MatchFilter = None, relaxed: bool = False) -> List[QgsPointLocator.Match] 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

Parameters
  • rect (QgsRectangle) –

  • filter (QgsPointLocator.MatchFilter = None) –

  • relaxed (bool = False) –

Return type

List[QgsPointLocator.Match]

extent(self) → QgsRectangle

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

New in version 2.14.

Return type

QgsRectangle

hasIndex(self) → bool

Indicate whether the data have been already indexed

Return type

bool

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

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

Parameters
  • maxFeaturesToIndex (int = -1) –

  • relaxed (bool = False) –

Return type

bool

initFinished

Emitted whenever index has been built and initialization is finished

Parameters

ok (bool) – False if the creation of index has been prematurely stopped due to the limit of features, otherwise True [signal]

isIndexing(self) → bool

Returns True if the point locator is currently indexing the data. This method is useful if constructor parameter relaxed is True

See also

QgsPointLocator

Return type

bool

isSignalConnected()
layer(self) → QgsVectorLayer

Gets associated layer

New in version 2.14.

Return type

QgsVectorLayer

nearestArea(self, point: QgsPointXY, tolerance: float, filter: QgsPointLocator.MatchFilter = None, relaxed: bool = False) → 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. This method is either blocking or non blocking according to relaxed parameter passed

New in version 3.0.

Parameters
  • point (QgsPointXY) –

  • tolerance (float) –

  • filter (QgsPointLocator.MatchFilter = None) –

  • relaxed (bool = False) –

Return type

QgsPointLocator.Match

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

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

Parameters
  • point (QgsPointXY) –

  • tolerance (float) –

  • filter (QgsPointLocator.MatchFilter = None) –

  • relaxed (bool = False) –

Return type

QgsPointLocator.Match

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

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

Parameters
  • point (QgsPointXY) –

  • tolerance (float) –

  • filter (QgsPointLocator.MatchFilter = None) –

  • relaxed (bool = False) –

Return type

QgsPointLocator.Match

pointInPolygon(self, point: QgsPointXY, relaxed: bool = False) → List[QgsPointLocator.Match]
Parameters
  • point (QgsPointXY) –

  • relaxed (bool = False) –

Return type

List[QgsPointLocator.Match]

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

maxFeaturesToIndex (int = -1) –

Return type

bool

receivers()
sender()
senderSignalIndex()
setExtent(self, extent: QgsRectangle)

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

New in version 2.14.

Parameters

extent (QgsRectangle) –

setRenderContext(self, context: QgsRenderContext)

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

New in version 3.2.

Parameters

context (QgsRenderContext) –

timerEvent()
verticesInRect(self, rect: QgsRectangle, filter: QgsPointLocator.MatchFilter = None, relaxed: bool = False) → List[QgsPointLocator.Match]

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

New in version 3.6.

verticesInRect(self, point: QgsPointXY, tolerance: float, filter: QgsPointLocator.MatchFilter = None, relaxed: bool = False) -> List[QgsPointLocator.Match] 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

New in version 3.6.

Parameters
  • rect (QgsRectangle) –

  • filter (QgsPointLocator.MatchFilter = None) –

  • relaxed (bool = False) –

Return type

List[QgsPointLocator.Match]

waitForIndexingFinished(self)

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