Class: QgsPointLocator¶
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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 correcttransformContext
if adestinationCrs
is specified. This is usually taken from the currentQgsProject.transformContext()
If
extent
is notNone
, 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
Returns how many geometries are cached in the index
Gets destination CRS - may be an invalid QgsCoordinateReferenceSystem if not doing OTF reprojection
Find edges within a specified recangle Optional filter may discard unwanted matches.
Gets extent of the area point locator covers - if
None
then it caches the whole layerIndicate whether the data have been already indexed
Prepare the index for queries.
Gets associated layer
Find nearest area to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.
Find nearest edge to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.
Find nearest vertex to the specified point - up to distance specified by tolerance Optional filter may discard unwanted matches.
find out if the point is in any polygons
Configure extent - if not
None
, it will index only that areaConfigure render context - if not
None
, it will use to index only visible featureFind vertices within a specified recangle Optional filter may discard unwanted matches.
Signals
Attributes
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All
= 7¶
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Area
= 4¶
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Edge
= 2¶
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Invalid
= 0¶
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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)
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distance
(self) → float¶ for vertex / edge match units depending on what class returns it (geom.cache: layer units, map canvas snapper: dest crs units)
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edgePoints
(self) → Tuple[QgsPointXY, QgsPointXY]¶ Only for a valid edge match - obtain endpoints of the edge
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featureId
(self) → int¶ The id of the feature to which the snapped geometry belongs.
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hasArea
(self) → bool¶
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hasEdge
(self) → bool¶
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hasVertex
(self) → bool¶
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isValid
(self) → bool¶
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layer
(self) → QgsVectorLayer¶ The vector layer where the snap occurred. Will be
None
if the snap happened on an intersection.
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point
(self) → QgsPointXY¶ for vertex / edge match coords depending on what class returns it (geom.cache: layer coords, map canvas snapper: dest coords)
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type
(self) → QgsPointLocator.Type¶
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vertexIndex
(self) → int¶ for vertex / edge match (first vertex of the edge)
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class
MatchFilter
¶ Bases:
sip.wrapper
QgsPointLocator.MatchFilter(QgsPointLocator.MatchFilter)
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acceptMatch
(self, match: QgsPointLocator.Match) → bool¶
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class
Type
¶ Bases:
int
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class
Types
¶ Bases:
sip.wrapper
QgsPointLocator.Types(Union[QgsPointLocator.Types, QgsPointLocator.Type]) QgsPointLocator.Types(QgsPointLocator.Types)
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Vertex
= 1¶
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cachedGeometryCount
(self) → int¶ Returns how many geometries are cached in the index
New in version 2.14.
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childEvent
()¶
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connectNotify
()¶
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customEvent
()¶
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destinationCrs
(self) → QgsCoordinateReferenceSystem¶ Gets destination CRS - may be an invalid QgsCoordinateReferenceSystem if not doing OTF reprojection
New in version 2.14.
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destroyIndex
(self)¶
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disconnectNotify
()¶
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edgesInRect
(self, rect: QgsRectangle, filter: QgsPointLocator.MatchFilter = None) → List[QgsPointLocator.Match]¶ Find edges within a specified recangle Optional filter may discard unwanted matches.
edgesInRect(self, point: QgsPointXY, tolerance: float, filter: QgsPointLocator.MatchFilter = None) -> List[QgsPointLocator.Match] Override of edgesInRect that construct rectangle from a center point and tolerance
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extent
(self) → QgsRectangle¶ Gets extent of the area point locator covers - if
None
then it caches the whole layerNew in version 2.14.
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hasIndex
(self) → bool¶ Indicate whether the data have been already indexed
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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, otherwiseTrue
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isSignalConnected
()¶
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layer
(self) → QgsVectorLayer¶ Gets associated layer
New in version 2.14.
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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.
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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.
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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.
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pointInPolygon
(self, point: QgsPointXY) → List[QgsPointLocator.Match]¶ find out if the point is in any polygons
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rebuildIndex
(self, maxFeaturesToIndex: int = -1) → bool¶
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receivers
()¶
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sender
()¶
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senderSignalIndex
()¶
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setExtent
(self, extent: QgsRectangle)¶ Configure extent - if not
None
, it will index only that areaNew in version 2.14.
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setRenderContext
(self, context: QgsRenderContext)¶ Configure render context - if not
None
, it will use to index only visible featureNew in version 3.2.
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timerEvent
()¶
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verticesInRect
(self, rect: QgsRectangle, filter: QgsPointLocator.MatchFilter = None) → List[QgsPointLocator.Match]¶ 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) -> List[QgsPointLocator.Match] Override of verticesInRect that construct rectangle from a center point and tolerance
New in version 3.6.
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