Class: QgsBatchGeocodeAlgorithm¶

class qgis.analysis.QgsBatchGeocodeAlgorithm¶

Bases: QgsProcessingFeatureBasedAlgorithm

A base class for batch geocoder algorithms, which takes a QgsGeocoderInterface object and exposes it as a Processing algorithm for batch geocoding operations.

Example¶

# create a class which implements the :py:class:`.QgsGeocoderInterface` interface:
class MyGeocoder(:py:class:`.QgsGeocoderInterface`):

   def geocodeString(self, string, context, feedback):
      # calculate and return results...

my_geocoder = MyGeocoder()

# create an algorithm which allows for batch geocoding operations using the custom geocoder interface
# and implement the few required pure virtual methods
class MyGeocoderAlgorithm(:py:class:`.QgsBatchGeocodeAlgorithm`):

    def __init__(self):
        super().__init__(my_geocoder)

    def displayName(self):
        return "My Geocoder"

    def name(self):
        return "my_geocoder_alg"

    def createInstance(self):
        return MyGeocoderAlgorithm()

    # optionally, the group(), groupId(), tags(), shortHelpString() and other metadata style methods can be overridden and customized:
    def tags(self):
        return 'geocode,my service,batch'

New in version 3.18.

QgsBatchGeocodeAlgorithm(geocoder: QgsGeocoderInterface) Constructor for QgsBatchGeocodeAlgorithm.

The geocoder must specify an instance of a class which implements the QgsGeocoderInterface interface. Ownership of geocoder is not transferred, and the caller must ensure that geocoder exists for the lifetime of this algorithm.

Methods

addOutput

Adds an output definition to the algorithm.

addParameter

Adds a parameter definition to the algorithm.

createInstance

Creates a new instance of the algorithm class.

group

rtype:

str

groupId

rtype:

str

initAlgorithm

initParameters

param configuration:

inputLayerTypes

rtype:

List[int]

inputParameterDescription

Returns the translated description of the parameter corresponding to the input layer.

inputParameterName

Returns the name of the parameter corresponding to the input layer.

invalidPointCloudError

Returns a user-friendly string to use as an error when a point cloud layer input could not be loaded.

invalidRasterError

Returns a user-friendly string to use as an error when a raster layer input could not be loaded.

invalidSinkError

Returns a user-friendly string to use as an error when a sink parameter could not be created.

invalidSourceError

Returns a user-friendly string to use as an error when a source parameter could not be loaded.

outputCrs

param inputCrs:

outputFields

param inputFields:

outputLayerType

Returns the layer type for layers generated by this algorithm, if this is possible to determine in advance.

outputName

rtype:

str

outputWkbType

param inputWkbType:

parameterAsAnnotationLayer

Evaluates the parameter with matching name to an annotation layer.

parameterAsBool

Evaluates the parameter with matching name to a static boolean value.

parameterAsBoolean

Evaluates the parameter with matching name to a static boolean value.

parameterAsColor

Evaluates the parameter with matching name to a color, or returns an invalid color if the parameter was not set.

parameterAsCompatibleSourceLayerPath

Evaluates the parameter with matching name to a source vector layer file path of compatible format.

parameterAsCompatibleSourceLayerPathAndLayerName

Evaluates the parameter with matching name to a source vector layer file path and layer name of compatible format.

parameterAsConnectionName

Evaluates the parameter with matching name to a connection name string.

parameterAsCrs

Evaluates the parameter with matching name to a coordinate reference system.

parameterAsDatabaseTableName

Evaluates the parameter with matching name to a database table name string.

parameterAsDateTime

Evaluates the parameter with matching name to a DateTime, or returns an invalid date time if the parameter was not set.

parameterAsDouble

Evaluates the parameter with matching name to a static double value.

parameterAsEnum

Evaluates the parameter with matching name to a enum value.

parameterAsEnumString

Evaluates the parameter with matching name to a static enum string.

parameterAsEnumStrings

Evaluates the parameter with matching name to list of static enum strings.

parameterAsEnums

Evaluates the parameter with matching name to list of enum values.

parameterAsExpression

Evaluates the parameter with matching name to an expression.

parameterAsExtent

Evaluates the parameter with matching name to a rectangular extent.

parameterAsExtentCrs

Returns the coordinate reference system associated with an extent parameter value.

parameterAsExtentGeometry

Evaluates the parameter with matching name to a rectangular extent, and returns a geometry covering this extent.

parameterAsFields

Evaluates the parameter with matching name to a list of fields.

parameterAsFile

Evaluates the parameter with matching name to a file/folder name.

parameterAsFileList

Evaluates the parameter with matching name to a list of files (for QgsProcessingParameterMultipleLayers in QgsProcessing:TypeFile mode).

parameterAsFileOutput

Evaluates the parameter with matching name to a file based output destination.

parameterAsGeometry

Evaluates the parameter with matching name to a geometry.

parameterAsGeometryCrs

Returns the coordinate reference system associated with a geometry parameter value.

parameterAsInt

Evaluates the parameter with matching name to a static integer value.

parameterAsInts

Evaluates the parameter with matching name to a list of integer values.

parameterAsLayer

Evaluates the parameter with matching name to a map layer.

parameterAsLayerList

Evaluates the parameter with matching name to a list of map layers.

parameterAsLayout

Evaluates the parameter with matching name to a print layout.

parameterAsLayoutItem

Evaluates the parameter with matching name to a print layout item, taken from the specified layout.

parameterAsMatrix

Evaluates the parameter with matching name to a matrix/table of values.

parameterAsMeshLayer

Evaluates the parameter with matching name to a mesh layer.

parameterAsOutputLayer

Evaluates the parameter with matching name to a output layer destination.

parameterAsPoint

Evaluates the parameter with matching name to a point.

parameterAsPointCloudLayer

Evaluates the parameter with matching name to a point cloud layer.

parameterAsPointCrs

Returns the coordinate reference system associated with an point parameter value.

parameterAsRange

Evaluates the parameter with matching name to a range of values.

parameterAsRasterLayer

Evaluates the parameter with matching name to a raster layer.

parameterAsSchema

Evaluates the parameter with matching name to a database schema name string.

parameterAsSink

Evaluates the parameter with matching name to a feature sink.

parameterAsSource

Evaluates the parameter with matching name to a feature source.

parameterAsString

Evaluates the parameter with matching name to a static string value.

parameterAsStrings

Evaluates the parameter with matching name to a list of strings (e.g. field names or point cloud attributes).

parameterAsVectorLayer

Evaluates the parameter with matching name to a vector layer.

postProcessAlgorithm

Allows the algorithm to perform any required cleanup tasks.

prepareAlgorithm

param parameters:

prepareSource

Read the source from parameters and context and set it

processAlgorithm

processFeature

param feature:

removeParameter

Removes the parameter with matching name from the algorithm, and deletes any existing definition.

request

Returns the feature request used for fetching features to process from the source layer.

sinkFlags

Returns the feature sink flags to be used for the output.

sinkProperties

sourceCrs

Returns the source's coordinate reference system.

sourceFlags

Returns the processing feature source flags to be used in the algorithm.

supportInPlaceEdit

param layer:

tags

rtype:

List[str]

writeFeatureError

Returns a user-friendly string to use as an error when a feature cannot be written into a sink.

addOutput(self, outputDefinition: QgsProcessingOutputDefinition) → bool¶

Adds an output definition to the algorithm. Ownership of the definition is transferred to the algorithm. Returns True if the output could be successfully added, or False if the output could not be added (e.g. as a result of a duplicate name).

This should usually be called from a subclass’ initAlgorithm() implementation.

Note that in some cases output creation can be automatically performed when calling addParameter(). See the notes in addParameter() for a description of when this occurs.

See also

addParameter()

See also

initAlgorithm()

addParameter(self, parameterDefinition: QgsProcessingParameterDefinition, createOutput: bool = True) → bool¶

Adds a parameter definition to the algorithm. Ownership of the definition is transferred to the algorithm. Returns True if parameter could be successfully added, or False if the parameter could not be added (e.g. as a result of a duplicate name).

This should usually be called from a subclass’ initAlgorithm() implementation.

If the createOutput argument is True, then a corresponding output definition will also be created (and added to the algorithm) where appropriate. E.g. when adding a QgsProcessingParameterVectorDestination and createOutput is True, then a QgsProcessingOutputVectorLayer output will be created and added to the algorithm. There is no need to call addOutput() to manually add a corresponding output for this vector. If createOutput is False then this automatic output creation will not occur.

See also

initAlgorithm()

See also

addOutput()

createInstance(self) → QgsProcessingAlgorithm¶

Creates a new instance of the algorithm class.

This method should return a ‘pristine’ instance of the algorithm class.

group(self) → str¶

Return type:: str

groupId(self) → str¶

Return type:: str

initAlgorithm(self, configuration: Dict[str, Any] = {})¶

initParameters(self, configuration: Dict[str, Any] = {})¶

Parameters:: configuration (Dict[str) –

inputLayerTypes(self) → List[int]¶

Return type:: List[int]

inputParameterDescription(self) → str¶

Returns the translated description of the parameter corresponding to the input layer.

By default this is a translated “Input layer” string.

New in version 3.12.

inputParameterName(self) → str¶

Returns the name of the parameter corresponding to the input layer.

By default this is the standard “INPUT” parameter name.

New in version 3.12.

invalidPointCloudError(parameters: Dict[str, Any], name: str) → str¶

Returns a user-friendly string to use as an error when a point cloud layer input could not be loaded.

The parameters argument should give the algorithms parameter map, and the name should correspond to the invalid point cloud parameter name.

See also

invalidSourceError()

See also

invalidSinkError()

See also

invalidRasterError()

New in version 3.32.

invalidRasterError(parameters: Dict[str, Any], name: str) → str¶

Returns a user-friendly string to use as an error when a raster layer input could not be loaded.

The parameters argument should give the algorithms parameter map, and the name should correspond to the invalid raster parameter name.

See also

invalidSourceError()

See also

invalidSinkError()

See also

invalidPointCloudError()

New in version 3.2.

invalidSinkError(parameters: Dict[str, Any], name: str) → str¶

Returns a user-friendly string to use as an error when a sink parameter could not be created.

The parameters argument should give the algorithms parameter map, and the name should correspond to the invalid sink parameter name.

See also

invalidSourceError()

See also

invalidRasterError()

See also

invalidPointCloudError()

New in version 3.2.

invalidSourceError(parameters: Dict[str, Any], name: str) → str¶

Returns a user-friendly string to use as an error when a source parameter could not be loaded.

The parameters argument should give the algorithms parameter map, and the name should correspond to the invalid source parameter name.

See also

invalidRasterError()

See also

invalidSinkError()

See also

invalidPointCloudError()

New in version 3.2.

outputCrs(self, inputCrs: QgsCoordinateReferenceSystem) → QgsCoordinateReferenceSystem¶

Parameters:: inputCrs (QgsCoordinateReferenceSystem) –
Return type:: QgsCoordinateReferenceSystem

outputFields(self, inputFields: QgsFields) → QgsFields¶

Parameters:: inputFields (QgsFields) –
Return type:: QgsFields

outputLayerType(self) → QgsProcessing.SourceType¶: Returns the layer type for layers generated by this algorithm, if this is possible to determine in advance.

outputName(self) → str¶

Return type:: str

outputWkbType(self, inputWkbType: Qgis.WkbType) → Qgis.WkbType¶

Parameters:: inputWkbType (Qgis.WkbType) –
Return type:: Qgis.WkbType

parameterAsAnnotationLayer(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → QgsAnnotationLayer¶

Evaluates the parameter with matching name to an annotation layer.

Annotation layers will be taken from context’s active project. Callers do not need to handle deletion of the returned layer.

Warning

Working with annotation layers is generally not thread safe (unless the layers are from a QgsProject loaded directly in a background thread). Ensure your algorithm returns the QgsProcessingAlgorithm.FlagNoThreading flag or only accesses annotation layers from a prepareAlgorithm() or postProcessAlgorithm() step.

New in version 3.22.

parameterAsBool(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → bool¶: Evaluates the parameter with matching name to a static boolean value.

parameterAsBoolean(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → bool¶: Evaluates the parameter with matching name to a static boolean value.

New in version 3.8.

parameterAsColor(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → QColor¶: Evaluates the parameter with matching name to a color, or returns an invalid color if the parameter was not set.

New in version 3.10.

parameterAsCompatibleSourceLayerPath(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext, compatibleFormats: Iterable[str], preferredFormat: str = '', feedback: QgsProcessingFeedback = None) → str¶

Evaluates the parameter with matching name to a source vector layer file path of compatible format.

If the parameter is evaluated to an existing layer, and that layer is not of the format listed in the compatibleFormats argument, then the layer will first be exported to a compatible format in a temporary location. The function will then return the path to that temporary file.

compatibleFormats should consist entirely of lowercase file extensions, e.g. ‘shp’.

The preferredFormat argument is used to specify to desired file extension to use when a temporary layer export is required.

When an algorithm is capable of handling multi-layer input files (such as Geopackage), it is preferable to use parameterAsCompatibleSourceLayerPathAndLayerName() which may avoid conversion in more situations.

parameterAsCompatibleSourceLayerPathAndLayerName(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext, compatibleFormats: Iterable[str], preferredFormat: str = '', feedback: QgsProcessingFeedback = None) → Tuple[str, str]¶

Evaluates the parameter with matching name to a source vector layer file path and layer name of compatible format.

If the parameter is evaluated to an existing layer, and that layer is not of the format listed in the compatibleFormats argument, then the layer will first be exported to a compatible format in a temporary location. The function will then return the path to that temporary file.

compatibleFormats should consist entirely of lowercase file extensions, e.g. ‘shp’.

The preferredFormat argument is used to specify to desired file extension to use when a temporary layer export is required. This defaults to shapefiles, because shapefiles are the future (don’t believe the geopackage hype!).

This method should be preferred over parameterAsCompatibleSourceLayerPath() when an algorithm is able to correctly handle files with multiple layers. Unlike parameterAsCompatibleSourceLayerPath(), it will not force a conversion in this case and will return the target layer name in the layerName argument.

Parameters:

parameters – input parameter value map
name – name of target parameter
context – processing context
compatibleFormats – a list of lowercase file extensions compatible with the algorithm
preferredFormat – preferred format extension to use if conversion if required
feedback – feedback object

Returns:

path to source layer, or nearly converted compatible layer
layerName: will be set to the target layer name for multi-layer sources (e.g. Geopackage)

New in version 3.10.

parameterAsConnectionName(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → str¶: Evaluates the parameter with matching name to a connection name string.

New in version 3.14.

parameterAsCrs(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → QgsCoordinateReferenceSystem¶: Evaluates the parameter with matching name to a coordinate reference system.

parameterAsDatabaseTableName(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → str¶: Evaluates the parameter with matching name to a database table name string.

New in version 3.14.

parameterAsDateTime(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → QDateTime¶: Evaluates the parameter with matching name to a DateTime, or returns an invalid date time if the parameter was not set.

New in version 3.14.

parameterAsDouble(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → float¶: Evaluates the parameter with matching name to a static double value.

parameterAsEnum(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → int¶: Evaluates the parameter with matching name to a enum value.

parameterAsEnumString(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → str¶: Evaluates the parameter with matching name to a static enum string.

New in version 3.18.

parameterAsEnumStrings(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → List[str]¶: Evaluates the parameter with matching name to list of static enum strings.

New in version 3.18.

parameterAsEnums(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → List[int]¶: Evaluates the parameter with matching name to list of enum values.

parameterAsExpression(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → str¶: Evaluates the parameter with matching name to an expression.

parameterAsExtent(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext, crs: QgsCoordinateReferenceSystem = QgsCoordinateReferenceSystem()) → QgsRectangle¶

Evaluates the parameter with matching name to a rectangular extent.

If crs is set, and the original coordinate reference system of the parameter can be determined, then the extent will be automatically reprojected so that it is in the specified crs. In this case the extent of the reproject rectangle will be returned.

See also

parameterAsExtentGeometry()

parameterAsExtentCrs(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → QgsCoordinateReferenceSystem¶: Returns the coordinate reference system associated with an extent parameter value.

See also

parameterAsExtent()

parameterAsExtentGeometry(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext, crs: QgsCoordinateReferenceSystem = QgsCoordinateReferenceSystem()) → QgsGeometry¶

Evaluates the parameter with matching name to a rectangular extent, and returns a geometry covering this extent.

If crs is set, and the original coordinate reference system of the parameter can be determined, then the extent will be automatically reprojected so that it is in the specified crs. Unlike parameterAsExtent(), the reprojected rectangle returned by this function will no longer be a rectangle itself (i.e. this method returns the geometry of the actual reprojected rectangle, while parameterAsExtent() returns just the extent of the reprojected rectangle).

See also

parameterAsExtent()

parameterAsFields(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → List[str]¶: Evaluates the parameter with matching name to a list of fields.

Deprecated since version use: parameterAsStrings() instead.

parameterAsFile(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → str¶: Evaluates the parameter with matching name to a file/folder name.

parameterAsFileList(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → List[str]¶: Evaluates the parameter with matching name to a list of files (for QgsProcessingParameterMultipleLayers in QgsProcessing:TypeFile mode).

New in version 3.10.

parameterAsFileOutput(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → str¶: Evaluates the parameter with matching name to a file based output destination.

parameterAsGeometry(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext, crs: QgsCoordinateReferenceSystem = QgsCoordinateReferenceSystem()) → QgsGeometry¶

Evaluates the parameter with matching name to a geometry.

If crs is set then the geometry will be automatically reprojected so that it is in the specified crs.

See also

parameterAsGeometryCrs()

parameterAsGeometryCrs(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → QgsCoordinateReferenceSystem¶: Returns the coordinate reference system associated with a geometry parameter value.

See also

parameterAsGeometry()

parameterAsInt(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → int¶: Evaluates the parameter with matching name to a static integer value.

parameterAsInts(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → List[int]¶: Evaluates the parameter with matching name to a list of integer values.

New in version 3.4.

parameterAsLayer(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → QgsMapLayer¶

Evaluates the parameter with matching name to a map layer.

Layers will either be taken from context’s active project, or loaded from external sources and stored temporarily in the context. In either case, callers do not need to handle deletion of the returned layer.

parameterAsLayerList(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext, flags: QgsProcessing.LayerOptionsFlags | QgsProcessing.LayerOptionsFlag = QgsProcessing.LayerOptionsFlags()) → List[QgsMapLayer]¶: Evaluates the parameter with matching name to a list of map layers. The flags are used to set options for loading layers (e.g. skip index generation).

parameterAsLayout(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → QgsPrintLayout¶: Evaluates the parameter with matching name to a print layout.

Warning

This method is not safe to run in a background thread, so it must either be used within a prepareAlgorithm implementation (which runs in the main thread), or the algorithm must return the FlagNoThreading flag.

New in version 3.8.

parameterAsLayoutItem(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext, layout: QgsPrintLayout) → QgsLayoutItem¶: Evaluates the parameter with matching name to a print layout item, taken from the specified layout.

Warning

This method is not safe to run in a background thread, so it must either be used within a prepareAlgorithm implementation (which runs in the main thread), or the algorithm must return the FlagNoThreading flag.

New in version 3.8.

parameterAsMatrix(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → List[Any]¶: Evaluates the parameter with matching name to a matrix/table of values. Tables are collapsed to a 1 dimensional list.

parameterAsMeshLayer(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → QgsMeshLayer¶

Evaluates the parameter with matching name to a mesh layer.

Layers will either be taken from context’s active project, or loaded from external sources and stored temporarily in the context. In either case, callers do not need to handle deletion of the returned layer.

New in version 3.6.

parameterAsOutputLayer(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → str¶: Evaluates the parameter with matching name to a output layer destination.

parameterAsPoint(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext, crs: QgsCoordinateReferenceSystem = QgsCoordinateReferenceSystem()) → QgsPointXY¶

Evaluates the parameter with matching name to a point.

If crs is set then the point will be automatically reprojected so that it is in the specified crs.

See also

parameterAsPointCrs()

parameterAsPointCloudLayer(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext, flags: QgsProcessing.LayerOptionsFlags | QgsProcessing.LayerOptionsFlag = QgsProcessing.LayerOptionsFlags()) → QgsPointCloudLayer¶

Evaluates the parameter with matching name to a point cloud layer. The flags are used to set options for loading layer (e.g. skip index generation).

Layers will either be taken from context’s active project, or loaded from external sources and stored temporarily in the context. In either case, callers do not need to handle deletion of the returned layer.

New in version 3.22.

parameterAsPointCrs(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → QgsCoordinateReferenceSystem¶: Returns the coordinate reference system associated with an point parameter value.

See also

parameterAsPoint()

parameterAsRange(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → List[float]¶: Evaluates the parameter with matching name to a range of values.

parameterAsRasterLayer(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → QgsRasterLayer¶

Evaluates the parameter with matching name to a raster layer.

Layers will either be taken from context’s active project, or loaded from external sources and stored temporarily in the context. In either case, callers do not need to handle deletion of the returned layer.

parameterAsSchema(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → str¶: Evaluates the parameter with matching name to a database schema name string.

New in version 3.14.

parameterAsSink(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext, fields: QgsFields, geometryType: Qgis.WkbType = Qgis.WkbType.NoGeometry, crs: QgsCoordinateReferenceSystem = QgsCoordinateReferenceSystem(), sinkFlags: QgsFeatureSink.SinkFlags | QgsFeatureSink.SinkFlag = QgsFeatureSink.SinkFlags(), createOptions: Dict[str, Any] = {}, datasourceOptions: Iterable[str] = [], layerOptions: Iterable[str] = []) → Tuple[QgsFeatureSink, str]¶

Evaluates the parameter with matching name to a feature sink.

Sinks will either be taken from context’s active project, or created from external providers and stored temporarily in the context.

The fields, geometryType and crs parameters dictate the properties of the resulting feature sink.

The destinationIdentifier argument will be set to a string which can be used to retrieve the layer corresponding to the sink, e.g. via calling QgsProcessingUtils.mapLayerFromString().

The createOptions argument is used to pass on creation options such as layer name.

The datasourceOptions and layerOptions arguments is used to pass on GDAL-specific format driver options.

This function creates a new object and the caller takes responsibility for deleting the returned object.

Raises:: QgsProcessingException –

parameterAsSource(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → QgsProcessingFeatureSource¶

Evaluates the parameter with matching name to a feature source.

Sources will either be taken from context’s active project, or loaded from external sources and stored temporarily in the context.

This function creates a new object and the caller takes responsibility for deleting the returned object.

parameterAsString(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → str¶: Evaluates the parameter with matching name to a static string value.

parameterAsStrings(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → List[str]¶: Evaluates the parameter with matching name to a list of strings (e.g. field names or point cloud attributes).

New in version 3.32.

parameterAsVectorLayer(self, parameters: Dict[str, Any], name: str, context: QgsProcessingContext) → QgsVectorLayer¶

Evaluates the parameter with matching name to a vector layer.

Layers will either be taken from context’s active project, or loaded from external sources and stored temporarily in the context. In either case, callers do not need to handle deletion of the returned layer.

postProcessAlgorithm(self, context: QgsProcessingContext, feedback: QgsProcessingFeedback) → Dict[str, Any]¶

Allows the algorithm to perform any required cleanup tasks. The returned variant map includes the results evaluated by the algorithm. These may be output layer references, or calculated values such as statistical calculations.

The context argument specifies the context in which the algorithm was run.

Postprocess progress should be reported using the supplied feedback object. Additionally, well-behaved algorithms should periodically check feedback to determine whether the post processing should be canceled and exited early.

postProcessAlgorithm should be used to handle any thread-sensitive cleanup which is required by the algorithm. It will always be called from the same thread that context has thread affinity with. While this will generally be the main thread, it is not guaranteed. For instance, algorithms which are run as a step in a larger model or as a subcomponent of a script-based algorithm will call postProcessAlgorithm from the same thread as that model/script it being executed in.

postProcessAlgorithm will not be called if the prepareAlgorithm() step failed (returned False), or if an exception was raised by the processAlgorithm() step.

Returns:: A map of algorithm outputs. These may be output layer references, or calculated values such as statistical calculations. Implementations which return a non-empty map will override any results returned by processAlgorithm().

See also

prepareAlgorithm()

See also

processAlgorithm()

prepareAlgorithm(self, parameters: Dict[str, Any], context: QgsProcessingContext, feedback: QgsProcessingFeedback) → bool¶

Parameters:

parameters (Dict[str) –
context (QgsProcessingContext) –
feedback (QgsProcessingFeedback) –

Return type:

bool

prepareSource(self, parameters: Dict[str, Any], context: QgsProcessingContext)¶: Read the source from parameters and context and set it

New in version 3.4.

processAlgorithm(self, parameters: Dict[str, Any], context: QgsProcessingContext, feedback: QgsProcessingFeedback) → Dict[str, Any]¶

processFeature(self, feature: QgsFeature, a1: QgsProcessingContext, feedback: QgsProcessingFeedback) → List[QgsFeature]¶

Parameters:

feature (QgsFeature) –
a1 (QgsProcessingContext) –
feedback (QgsProcessingFeedback) –

Return type:

List[QgsFeature]

removeParameter(self, name: str)¶: Removes the parameter with matching name from the algorithm, and deletes any existing definition.

request(self) → QgsFeatureRequest¶: Returns the feature request used for fetching features to process from the source layer. The default implementation requests all attributes and geometry.

sinkFlags(self) → QgsFeatureSink.SinkFlags¶: Returns the feature sink flags to be used for the output.

New in version 3.4.1.

sinkProperties(self, sink: str, parameters: Dict[str, Any], context: QgsProcessingContext, sourceProperties: Dict[str, QgsProcessingAlgorithm.VectorProperties]) → QgsProcessingAlgorithm.VectorProperties¶

sourceCrs(self) → QgsCoordinateReferenceSystem¶: Returns the source’s coordinate reference system. This will only return a valid CRS when called from a subclasses’ processFeature() implementation.

sourceFlags(self) → QgsProcessingFeatureSource.Flag¶: Returns the processing feature source flags to be used in the algorithm.

supportInPlaceEdit(self, layer: QgsMapLayer) → bool¶

Parameters:: layer (QgsMapLayer) –
Return type:: bool

tags(self) → List[str]¶

Return type:: List[str]

writeFeatureError(sink: QgsFeatureSink, parameters: Dict[str, Any], name: str) → str¶

Returns a user-friendly string to use as an error when a feature cannot be written into a sink.

The sink argument is the sink into which the feature cannot be written.

The parameters argument should give the algorithms parameter map, and the name should correspond to the sink parameter name.

New in version 3.22.