Class: QgsGeometryCheck¶
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class
qgis.analysis.
QgsGeometryCheck
(context: QgsGeometryCheckContext, configuration: Dict[str, Any])¶ Bases:
sip.wrapper
Create a new geometry check.
QgsGeometryCheck(QgsGeometryCheck)
This class implements a geometry check.
Geometry checks run over a set of features and can detect errors like topological or other issues which are reported in the geometry validation panel in QGIS and help a user to create valid geometries.
Implementing a custom geometry check consists of the following parts
### Writing the check
A new subclass of QgsGeometryCheck needs to be written and at least the following abstract methods need to be implemented:
compatibleGeometryTypes()
A list of geometry types to which this check applies
resolutionMethods()
A list of names for (automated) resolution methods that can be used to fix errors of this type
description()
A description for the geometry check.
id()
A unique id for this check.
checkType()
One of QgsGeometryCheck.LayerCheck, QgsGeometryCheck.FeatureCheck,QgsGeometryCheck.FeatureNodeCheck
link collectErrors() collectErrors(featurePools, errors, messages, feedback, ids)endlink
This method will be called to validate geometries. All geometries which should be validated are passed into this method with the parameter ids and should be retrieved from the available featurePools to make use of caching. New errors should be appended to the error list and other message strings to messages. The method needs to return a tuple (errors, messages).
### Creating a geometry check factory
A Geometry check factory manages meta information for checks. There will always be one single geometry check factory created per check type, but it’s possible that multiple QgsGeometryCheck instances are created and used in parallel.
A new subclass of QgsGeometryCheckFactory needs to be written and at least the following abstract methods need to be implemented:
link QgsGeometryCheckFactory.createGeometryCheck() createGeometryCheck(context, configuration)endlink
Needs to return a new subclassed QgsGeometryCheck object that has been written in the previous step.
link QgsGeometryCheckFactory.id() `id()endlink
A unique id for this geometry check.
link QgsGeometryCheckFactory.description() `description()endlink
A description for this geometry check that can be presented to the user for more explanation.
link QgsGeometryCheckFactory.isCompatible() QgsGeometryCheckFactory.isCompatible(layer)endlink
Returns a boolean that determines if this check is available for a given layer. This often checks for the geometry type of the layer.
link QgsGeometryCheckFactory.flags() flags()endlink
Returns additional flags for a geometry check. If unsure return QgsGeometryCheck.AvailableInValidation.
link QgsGeometryCheckFactory.checkType() checkType()endlink
Returns the type of this geometry check.
### Registering the geometry check
Finally the geometry check factory needs to be registered in QGIS, so the system is aware of the available geometry checks.
# Make sure you always keep a checkFactory = MyGeometryCheckFactory() QgsAnalysis.geometryCheckRegistry().registerGeometryCheck(checkFactory)
Note
This class is a technology preview and unstable API.
New in version 3.4: Enums
Methods
Returns the check type.
The main worker method.
A list of geometry types for which this check can be performed.
Returns the context
Returns a human readable description for this check.
Flags for this geometry check.
Returns an id for this check.
Returns if this geometry check is compatible with
layer
.Returns a list of descriptions for available resolutions for errors.
Signals
Attributes
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AvailableInValidation
= 2¶
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class
Change
¶ Bases:
sip.wrapper
QgsGeometryCheck.Change(_what: QgsGeometryCheck.ChangeWhat, _type: QgsGeometryCheck.ChangeType, _vidx: QgsVertexId = QgsVertexId()) Create a new Change
QgsGeometryCheck.Change(QgsGeometryCheck.Change)
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type
¶
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vidx
¶
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what
¶
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ChangeAdded
= 0¶
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ChangeChanged
= 2¶
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ChangeFeature
= 0¶
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ChangeNode
= 3¶
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ChangePart
= 1¶
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ChangeRemoved
= 1¶
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ChangeRing
= 2¶
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class
ChangeType
¶ Bases:
int
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class
ChangeWhat
¶ Bases:
int
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class
CheckType
¶ Bases:
int
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FeatureCheck
= 1¶
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FeatureNodeCheck
= 0¶
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class
Flag
¶ Bases:
int
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class
Flags
¶ Bases:
sip.wrapper
QgsGeometryCheck.Flags(Union[QgsGeometryCheck.Flags, QgsGeometryCheck.Flag]) QgsGeometryCheck.Flags(QgsGeometryCheck.Flags)
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baseClass
¶ alias of
QgsGeometryCheck
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LayerCheck
= 2¶
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class
LayerFeatureIds
¶ Bases:
sip.wrapper
QgsGeometryCheck.LayerFeatureIds(QgsGeometryCheck.LayerFeatureIds)
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checkType
(self) → QgsGeometryCheck.CheckType¶ Returns the check type.
New in version 3.4.
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collectErrors
(self, featurePools: object, errors: Iterable[QgsGeometryCheckError], messages: Iterable[str], feedback: QgsFeedback, ids: QgsGeometryCheck.LayerFeatureIds = QgsGeometryCheck.LayerFeatureIds()) → Tuple[List[QgsGeometryCheckError], List[str]]¶ The main worker method. Check all features available from
featurePools
and write errors found toerrors
. Other status messages can be written tomessages
. Progress should be reported tofeedback
. Only features and layers listed inids
should be checked.New in version 3.4.
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compatibleGeometryTypes
(self) → object¶ A list of geometry types for which this check can be performed.
New in version 3.4.
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context
(self) → QgsGeometryCheckContext¶ Returns the context
New in version 3.4.
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description
(self) → str¶ Returns a human readable description for this check.
New in version 3.4.
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flags
(self) → QgsGeometryCheck.Flags¶ Flags for this geometry check.
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id
(self) → str¶ Returns an id for this check.
New in version 3.4.
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isCompatible
(self, layer: QgsVectorLayer) → bool¶ Returns if this geometry check is compatible with
layer
. By default it checks for the geometry type in ``compatibleGeometryTypes``().New in version 3.4.
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resolutionMethods
(self) → List[str]¶ Returns a list of descriptions for available resolutions for errors. The index will be passed as
method
tofixError()
.New in version 3.4.
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staticMetaObject
= <PyQt5.QtCore.QMetaObject object>¶