Subgroup: Vector
Class: QgsVectorLayer¶
-
class
qgis.core.
QgsVectorLayer
¶ Bases:
qgis._core.QgsMapLayer
,qgis._core.QgsExpressionContextGenerator
,qgis._core.QgsExpressionContextScopeGenerator
,qgis._core.QgsFeatureSink
,qgis._core.QgsFeatureSource
Represents a vector layer which manages a vector based data sets.
The QgsVectorLayer is instantiated by specifying the name of a data provider, such as postgres or wfs, and url defining the specific data set to connect to. The vector layer constructor in turn instantiates a QgsVectorDataProvider subclass corresponding to the provider type, and passes it the url. The data provider connects to the data source.
The QgsVectorLayer provides a common interface to the different data types. It also manages editing transactions.
Sample usage of the QgsVectorLayer class:
The main data providers supported by QGIS are listed below.
section providers Vector data providers
subsection memory Memory data providerType (memory)
The memory data provider is used to construct in memory data, for example scratch data or data generated from spatial operations such as contouring. There is no inherent persistent storage of the data. The data source uri is constructed. The url specifies the geometry type (“point”, “linestring”, “polygon”, “multipoint”,”multilinestring”,”multipolygon”), optionally followed by url parameters as follows:
- crs=definition
Defines the coordinate reference system to use for the layer. definition is any string accepted by
QgsCoordinateReferenceSystem.createFromString()
- index=yes
Specifies that the layer will be constructed with a spatial index
- field=name:type(length,precision)
Defines an attribute of the layer. Multiple field parameters can be added to the data provider definition. type is one of “integer”, “double”, “string”.
An example url is “Point?crs=epsg:4326&field=id:integer&field=name:string(20)&index=yes”
subsection ogr OGR data provider (ogr)
Accesses data using the OGR drivers (http://www.gdal.org/ogr/ogr_formats.html). The url is the OGR connection string. A wide variety of data formats can be accessed using this driver, including file based formats used by many GIS systems, database formats, and web services. Some of these formats are also supported by custom data providers listed below.
subsection spatialite SpatiaLite data provider (spatialite)
Access data in a SpatiaLite database. The url defines the connection parameters, table, geometry column, and other attributes. The url can be constructed using the QgsDataSourceUri class.
subsection postgres PostgreSQL data provider (postgres)
Connects to a PostgreSQL database. The url defines the connection parameters, table, geometry column, and other attributes. The url can be constructed using the QgsDataSourceUri class.
subsection mssql Microsoft SQL server data provider (mssql)
Connects to a Microsoft SQL server database. The url defines the connection parameters, table, geometry column, and other attributes. The url can be constructed using the QgsDataSourceUri class.
subsection wfs WFS (web feature service) data provider (wfs)
Used to access data provided by a web feature service.
The url can be a HTTP url to a WFS server (legacy, e.g. http://foobar/wfs?TYPENAME=xxx&SRSNAME=yyy[&FILTER=zzz]), or, starting with QGIS 2.16, a URI constructed using the QgsDataSourceUri class with the following parameters : - url=string (mandatory): HTTP url to a WFS server endpoint. e.g http://foobar/wfs - typename=string (mandatory): WFS typename - srsname=string (recommended): SRS like ‘EPSG:XXXX’ - username=string - password=string - authcfg=string - version=auto/1.0.0/1.1.0/2.0.0 -sql=string: full SELECT SQL statement with optional WHERE, ORDER BY and possibly with JOIN if supported on server - filter=string: QGIS expression or OGC/FES filter - restrictToRequestBBOX=1: to download only features in the view extent (or more generally in the bounding box of the feature iterator) - maxNumFeatures=number - IgnoreAxisOrientation=1: to ignore EPSG axis order for WFS 1.1 or 2.0 - InvertAxisOrientation=1: to invert axis order - hideDownloadProgressDialog=1: to hide the download progress dialog
The ‘FILTER’ query string parameter can be used to filter the WFS feature type. The ‘FILTER’ key value can either be a QGIS expression or an OGC XML filter. If the value is set to a QGIS expression the driver will turn it into OGC XML filter before passing it to the WFS server. Beware the QGIS expression filter only supports” =, !=, <, >, <=, >=, AND, OR, NOT, LIKE, IS NULL” attribute operators, “BBOX, Disjoint, Intersects, Touches, Crosses, Contains, Overlaps, Within” spatial binary operators and the QGIS local “geomFromWKT, geomFromGML” geometry constructor functions.
Also note:
- You can use various functions available in the QGIS Expression list,
however the function must exist server side and have the same name and arguments to work.
- Use the special $geometry parameter to provide the layer geometry column as input
into the spatial binary operators e.g intersects($geometry, geomFromWKT(‘POINT (5 6)’))
subsection delimitedtext Delimited text file data provider (delimitedtext)
Accesses data in a delimited text file, for example CSV files generated by spreadsheets. The contents of the file are split into columns based on specified delimiter characters. Each record may be represented spatially either by an X and Y coordinate column, or by a WKT (well known text) formatted columns.
The url defines the filename, the formatting options (how the text in the file is divided into data fields, and which fields contain the X,Y coordinates or WKT text definition. The options are specified as url query items.
At its simplest the url can just be the filename, in which case it will be loaded as a CSV formatted file.
The url may include the following items:
- encoding=UTF-8
Defines the character encoding in the file. The default is UTF-8. To use the default encoding for the operating system use “System”.
- type=(csv|regexp|whitespace|plain)
Defines the algorithm used to split records into columns. Records are defined by new lines, except for csv format files for which quoted fields may span multiple records. The default type is csv.
- “csv” splits the file based on three sets of characters:
delimiter characters, quote characters, and escape characters. Delimiter characters mark the end of a field. Quote characters enclose a field which can contain delimiter characters, and newlines. Escape characters cause the following character to be treated literally (including delimiter, quote, and newline characters). Escape and quote characters must be different from delimiter characters. Escape characters that are also quote characters are treated specially - they can only escape themselves within quotes. Elsewhere they are treated as quote characters. The defaults for delimiter, quote, and escape are ‘,’, ‘”’, ‘”’. - “regexp” splits each record using a regular expression (see QRegExp documentation for details). - “whitespace” splits each record based on whitespace (on or more whitespace characters. Leading whitespace in the record is ignored. - “plain” is provided for backwards compatibility. It is equivalent to CSV except that the default quote characters are single and double quotes, and there is no escape characters.
- delimiter=characters
Defines the delimiter characters used for csv and plain type files, or the regular expression for regexp type files. It is a literal string of characters except that “t” may be used to represent a tab character.
- quote=characters
Defines the characters that are used as quote characters for csv and plain type files.
- escape=characters
Defines the characters used to escape delimiter, quote, and newline characters.
- skipLines=n
Defines the number of lines to ignore at the beginning of the file (default 0)
- useHeader=(yes|no)
Defines whether the first record in the file (after skipped lines) contains column names (default yes)
- trimFields=(yes|no)
If yes then leading and trailing whitespace will be removed from fields
- skipEmptyFields=(yes|no)
If yes then empty fields will be discarded (equivalent to concatenating consecutive delimiters)
- maxFields=#
Specifies the maximum number of fields to load for each record. Additional fields will be discarded. Default is 0 - load all fields.
- decimalPoint=c
Defines a character that is used as a decimal point in the numeric columns The default is ‘.’.
- xField=column yField=column
Defines the name of the columns holding the x and y coordinates for XY point geometries. If the useHeader is no (ie there are no column names), then this is the column number (with the first column as 1).
- xyDms=(yes|no)
If yes then the X and Y coordinates are interpreted as degrees/minutes/seconds format (fairly permissively), or degree/minutes format.
- wktField=column
Defines the name of the columns holding the WKT geometry definition for WKT geometries. If the useHeader is no (ie there are no column names), then this is the column number (with the first column as 1).
- geomType=(point|line|polygon|none)
Defines the geometry type for WKT type geometries. QGIS will only display one type of geometry for the layer - any others will be ignored when the file is loaded. By default the provider uses the type of the first geometry in the file. Use geomType to override this type.
geomType can also be set to none, in which case the layer is loaded without geometries.
- subset=expression
Defines an expression that will identify a subset of records to display
- crs=crsstring
Defines the coordinate reference system used for the layer. This can be any string accepted by
QgsCoordinateReferenceSystem.createFromString()
-subsetIndex=(yes|no)
Determines whether the provider generates an index to improve the efficiency of subsets. The default is yes
-spatialIndex=(yes|no)
Determines whether the provider generates a spatial index. The default is no.
-watchFile=(yes|no)
Defines whether the file will be monitored for changes. The default is to monitor for changes.
- quiet
Errors encountered loading the file will not be reported in a user dialog if quiet is included (They will still be shown in the output log).
subsection gpx GPX data provider (gpx)
Provider reads tracks, routes, and waypoints from a GPX file. The url defines the name of the file, and the type of data to retrieve from it (“track”, “route”, or “waypoint”).
An example url is “/home/user/data/holiday.gpx?type=route”
subsection grass Grass data provider (grass)
Provider to display vector data in a GRASS GIS layer.
TODO QGIS3: Remove virtual from non-inherited methods (like isModified)
See also
Methods
abstract
Returns the abstract of the layer used by QGIS Server in GetCapabilities request. actions
Get all layer actions defined on this layer. addAttribute
Add an attribute field (but does not commit it) addCurvedPart
addCurvedRing
Adds a ring to polygon/multipolygon features (takes ownership) addExpressionField
Add a new field which is calculated by the expression specified addFeature
addFeatures
addJoin
Joins another vector layer to this layer addPart
Adds a new part polygon to a multipart feature addPartV2
Adds a new part polygon to a multipart feature addRing
Adds a ring to polygon/multipolygon features addTopologicalPoints
Adds topological points for every vertex of the geometry. aggregate
Calculates an aggregated value from the layer’s features. allFeatureIds
Returns a list of all feature IDs for features present in the source. appendError
attributeAlias
Returns the alias of an attribute name or a null string if there is no alias. attributeAliases
Returns a map of field name to attribute alias attributeDisplayName
Convenience function that returns the attribute alias if defined or the field name else attributeList
Returns list of attribute indexes. attributeTableConfig
Get the attribute table configuration object. attribution
Returns the attribution of the layer used by QGIS Server in GetCapabilities request. attributionUrl
Returns the attribution URL of the layer used by QGIS Server in GetCapabilities request. autoRefreshInterval
Returns the auto refresh interval (in milliseconds). auxiliaryLayer
Returns the current auxiliary layer. beginEditCommand
Create edit command for undo/redo operations blendMode
Returns the current blending mode for a layer. blockSignals
boundingBoxOfSelected
Returns the bounding box of the selected features. capabilitiesString
Capabilities for this layer, comma separated and translated. changeAttributeValue
Changes an attribute value for a feature (but does not immediately commit the changes). changeGeometry
Changes a feature’s geometry
within the layer’s edit buffer (but does not immediately commit the changes).childEvent
children
clone
Returns a new instance equivalent to this one. commitChanges
Attempts to commit to the underlying data provider any buffered changes made since the last to call to startEditing(). commitErrors
Returns a list containing any error messages generated when attempting to commit changes to the layer. conditionalStyles
Return the conditional styles that are set for this layer. connectNotify
constraintDescription
Returns the descriptive name for the constraint expression for a specified field index. constraintExpression
Returns the constraint expression for for a specified field index, if set. countSymbolFeatures
Count features for symbols. createExpressionContext
createExpressionContextScope
createMapRenderer
Return new instance of QgsMapLayerRenderer that will be used for rendering of given context crs
Returns the layer’s spatial reference system. customEvent
customProperty
Read a custom property from layer. customPropertyKeys
Returns list of all keys within custom properties. dataComment
Returns a description for this layer as defined in the data provider. dataProvider
dataUrl
Returns the DataUrl of the layer used by QGIS Server in GetCapabilities request. dataUrlFormat
Returns the DataUrl format of the layer used by QGIS Server in GetCapabilities request. defaultValue
Returns the calculated default value for the specified field index. defaultValueDefinition
Returns the definition of the expression used when calculating the default value for a field. deleteAttribute
Deletes an attribute field (but does not commit it). deleteAttributes
Deletes a list of attribute fields (but does not commit it) deleteFeature
Deletes a feature from the layer (but does not commit it). deleteFeatures
Deletes a set of features from the layer (but does not commit it) deleteLater
deleteSelectedFeatures
Deletes the selected features deleteStyleFromDatabase
Delete a style from the database deleteVertex
Deletes a vertex from a feature. dependencies
Gets the list of dependencies. deselect
Deselect feature by its ID destroyEditCommand
Destroy active command and reverts all changes in it diagramLayerSettings
diagramRenderer
diagramsEnabled
Returns whether the layer contains diagrams which are enabled and should be drawn. disconnect
disconnectNotify
displayExpression
Get the preview expression, used to create a human readable preview string. displayField
This is a shorthand for accessing the displayExpression if it is a simple field. drawVertexMarker
Draws a vertex symbol at (screen) coordinates x, y. dumpObjectInfo
dumpObjectTree
dynamicPropertyNames
editBuffer
Buffer with uncommitted editing operations. editFormConfig
Get the configuration of the form used to represent this vector layer. editorWidgetSetup
The editor widget setup defines which QgsFieldFormatter and editor widget will be used for the field at index. emitStyleChanged
Triggers an emission of the styleChanged() signal. endEditCommand
Finish edit command and add it to undo/redo stack error
Get current status error. event
eventFilter
excludeAttributesWfs
A set of attributes that are not advertised in WFS requests with QGIS server. excludeAttributesWms
A set of attributes that are not advertised in WMS requests with QGIS server. exportNamedMetadata
Export the current metadata of this layer as named metadata in a QDomDocument exportNamedStyle
Export the properties of this layer as named style in a QDomDocument exportSldStyle
Export the properties of this layer as SLD style in a QDomDocument expressionField
Returns the expression used for a given expression field extensionPropertyType
Returns the extension of a Property. extent
featureBlendMode
Returns the current blending mode for features featureCount
Number of features rendered with specified legend key. fieldConstraints
Returns any constraints which are present for a specified field index. fieldConstraintsAndStrength
Returns a map of constraint with their strength for a specific field of the layer. fields
Returns the list of fields of this layer. findChild
findChild(self, Tuple, name: str = ‘’, options: Union[Qt.FindChildOptions, Qt.FindChildOption] = Qt.FindChildrenRecursively) -> QObject findChildren
findChildren(self, Tuple, name: str = ‘’, options: Union[Qt.FindChildOptions, Qt.FindChildOption] = Qt.FindChildrenRecursively) -> List[QObject] flushBuffer
Flushes any internal buffer which may exist in the sink, causing any buffered features to be added to the sink’s destination. formatLayerName
A convenience function to capitalize and format a layer name
.geometryType
Returns point, line or polygon getDoubleValues
Fetches all double values from a specified field name or expression. getFeature
Query the layer for the feature with the given id. getFeatures
Query the layer for features specified in request. getSelectedFeatures
Get an iterator of the selected features getStyleFromDatabase
Will return the named style corresponding to style id provided getValues
Fetches all values from a specified field name or expression. hasAutoRefreshEnabled
Returns true if auto refresh is enabled for the layer. hasDependencyCycle
hasScaleBasedVisibility
Returns whether scale based visibility is enabled for the layer. htmlMetadata
id
Returns the layer’s unique ID, which is used to access this layer from QgsProject
.importNamedMetadata
Import the metadata of this layer from a QDomDocument importNamedStyle
Import the properties of this layer from a QDomDocument inherits
insertVertex
Insert a new vertex before the given vertex number, installEventFilter
invertSelection
Select not selected features and deselect selected ones invertSelectionInRectangle
Invert selection of features found within the search rectangle (in layer’s coordinates) isAuxiliaryField
Returns true if the field comes from the auxiliary layer, false otherwise. isEditCommandActive
Test if an edit command is active isEditable
Returns true if the provider is in editing mode isInScaleRange
Tests whether the layer should be visible at the specified scale
.isModified
Returns true if the provider has been modified since the last commit isRefreshOnNotifyEnabled
Returns true if the refresh on provider nofification is enabled isSignalConnected
isSpatial
Returns true if this is a geometry layer and false in case of NoGeometry (table only) or UnknownGeometry isValid
Return the status of the layer. isWidgetType
isWindowType
joinBuffer
Accessor to the join buffer object keywordList
Returns the keyword list of the layer used by QGIS Server in GetCapabilities request. killTimer
labeling
Access to labeling configuration. labelsEnabled
Returns whether the layer contains labels which are enabled and should be drawn. legend
Can be null. legendUrl
Returns the URL for the layer’s legend. legendUrlFormat
Returns the format for a URL based layer legend. listStylesInDatabase
Lists all the style in db split into related to the layer and not related to loadAuxiliaryLayer
Loads the auxiliary layer for this vector layer. loadDefaultMetadata
Retrieve the default metadata for this layer if one loadDefaultStyle
Retrieve the default style for this layer if one loadNamedMetadata
Retrieve a named metadata for this layer if one loadNamedMetadataFromDatabase
Retrieve a named metadata for this layer from a sqlite database. loadNamedStyle
Load a named style from file/local db/datasource db loadNamedStyleFromDatabase
Retrieve a named style for this layer from a sqlite database. loadSldStyle
Attempts to style the layer using the formatting from an SLD type file. mapTipTemplate
The mapTip is a pretty, html representation for feature information. materialize
Materializes a request
(query) made against this feature source, by running it over the source and returning a new memory based vector layer containing the result.maximumScale
Returns the maximum map scale (i.e. maximumValue
Returns the maximum value for an attribute column or an invalid variant in case of error. metaObject
metadata
Returns a reference to the layer’s metadata store. metadataUri
Retrieve the metadata URI for this layer metadataUrl
Returns the metadata URL of the layer used by QGIS Server in GetCapabilities request. metadataUrlFormat
Returns the metadata format of the layer used by QGIS Server in GetCapabilities request. metadataUrlType
Returns the metadata type of the layer used by QGIS Server in GetCapabilities request. minimumScale
Returns the minimum map scale (i.e. minimumValue
Returns the minimum value for an attribute column or an invalid variant in case of error. modifySelection
Modifies the current selection on this layer moveToThread
moveVertex
Moves the vertex at the given position number, moveVertexV2
Moves the vertex at the given position number, name
Returns the display name of the layer. objectName
opacity
Returns the opacity for the vector layer, where opacity is a value between 0 (totally transparent) and 1.0 (fully opaque). parent
pendingAllAttributesList
Returns list of attribute indexes. pendingFeatureCount
Returns feature count including changes which have not yet been committed pendingFields
Returns the list of fields of this layer. pendingPkAttributesList
Returns list of attributes making up the primary key pkAttributeList
Returns list of attributes making up the primary key property
providerType
Return the provider type for this layer publicSource
Gets a version of the internal layer definition that has sensitive bits removed (for example, the password). pyqtConfigure
Each keyword argument is either the name of a Qt property or a Qt signal. readCommonStyle
readCustomProperties
readExtentFromXml
Returns true if the extent is read from the XML document when data source has no metadata, false if it’s the data provider which determines it. readLayerXml
Sets state from Dom document readOnly
Returns if this layer is read only. readSld
readStyle
Read the style for the current layer from the Dom node supplied. readStyleManager
readSymbology
Read the symbology for the current layer from the Dom node supplied. readXml
Reads vector layer specific state from project file Dom node. receivers
referencingRelations
Get relations, where the foreign key is on this layer refreshOnNotifyMessage
Returns the message that should be notified by the provider to triggerRepaint reload
Synchronises with changes in the datasource removeCustomProperty
Remove a custom property from layer. removeEventFilter
removeExpressionField
Remove an expression field removeFieldAlias
Removes an alias (a display name) for attributes to display in dialogs removeFieldConstraint
Removes a constraint for a specified field index. removeJoin
Removes a vector layer join removeSelection
Clear selection renameAttribute
Renames an attribute field (but does not commit it). renderer
Return renderer. renderer3D
Returns 3D renderer associated with the layer. resolveReferences
Resolve references to other layers (kept as layer IDs after reading XML) into layer objects. rollBack
Stops a current editing operation and discards any uncommitted edits. saveDefaultMetadata
Save the current metadata of this layer as the default metadata saveDefaultStyle
Save the properties of this layer as the default style saveNamedMetadata
Save the current metadata of this layer as a named metadata saveNamedStyle
Save the properties of this layer as a named style saveSldStyle
Saves the properties of this layer to an SLD format file. saveStyleToDatabase
Save named and sld style of the layer to the style table in the db. select
Select feature by its ID selectAll
Select all the features selectByExpression
Select matching features using an expression. selectByIds
Select matching features using a list of feature IDs. selectByRect
Select features found within the search rectangle (in layer’s coordinates) selectedFeatureCount
The number of features that are selected in this layer selectedFeatureIds
Return reference to identifiers of selected features selectedFeatures
Get a copy of the user-selected features sender
senderSignalIndex
setAbstract
Sets the abstract of the layer used by QGIS Server in GetCapabilities request. setAttributeTableConfig
Set the attribute table configuration object. setAttribution
Sets the attribution of the layer used by QGIS Server in GetCapabilities request. setAttributionUrl
Sets the attribution URL of the layer used by QGIS Server in GetCapabilities request. setAutoRefreshEnabled
Sets whether auto refresh is enabled for the layer. setAutoRefreshInterval
Sets the auto refresh interval (in milliseconds) for the layer. setAuxiliaryLayer
Sets the current auxiliary layer. setBlendMode
Set the blending mode used for rendering a layer. setConstraintExpression
Set the constraint expression for the specified field index. setCoordinateSystem
Setup the coordinate system transformation for the layer setCrs
Sets layer’s spatial reference system setCustomProperties
Set custom properties for layer. setCustomProperty
Set a custom property for layer. setDataSource
Update the data source of the layer. setDataUrl
Sets the DataUrl of the layer used by QGIS Server in GetCapabilities request. setDataUrlFormat
Sets the DataUrl format of the layer used by QGIS Server in GetCapabilities request. setDefaultValueDefinition
Sets the definition of the expression to use when calculating the default value for a field. setDependencies
Sets the list of dependencies. setDiagramLayerSettings
setDiagramRenderer
Sets diagram rendering object (takes ownership) setDisplayExpression
Set the preview expression, used to create a human readable preview string. setEditFormConfig
Get the configuration of the form used to represent this vector layer. setEditorWidgetSetup
copydoc editorWidgetSetup setError
setExcludeAttributesWfs
A set of attributes that are not advertised in WFS requests with QGIS server. setExcludeAttributesWms
A set of attributes that are not advertised in WMS requests with QGIS server. setExtent
Set the extent setFeatureBlendMode
Set the blending mode used for rendering each feature setFieldAlias
Sets an alias (a display name) for attributes to display in dialogs setFieldConstraint
Sets a constraint for a specified field index. setKeywordList
Sets the keyword list of the layer used by QGIS Server in GetCapabilities request. setLabeling
Set labeling configuration. setLayerOrder
Reorders the previously selected sublayers of this layer from bottom to top. setLegend
Assign a legend controller to the map layer. setLegendUrl
Sets the URL for the layer’s legend. setLegendUrlFormat
Sets the format for a URL based layer legend. setMapTipTemplate
The mapTip is a pretty, html representation for feature information. setMaximumScale
Sets the maximum map scale
(i.e.setMetadata
Sets the layer’s metadata
store.setMetadataUrl
Sets the metadata URL of the layer used by QGIS Server in GetCapabilities request. setMetadataUrlFormat
Sets the metadata format of the layer used by QGIS Server in GetCapabilities request. setMetadataUrlType
Set the metadata type of the layer used by QGIS Server in GetCapabilities request MetadataUrlType indicates the standard to which the metadata complies. setMinimumScale
Sets the minimum map scale
(i.e.setName
Set the display name
of the layer.setObjectName
setOpacity
Sets the opacity
for the vector layer, whereopacity
is a value between 0 (totally transparent) and 1.0 (fully opaque).setParent
setProperty
setProviderEncoding
Sets the textencoding of the data provider setReadExtentFromXml
Flag allowing to indicate if the extent has to be read from the XML document when data source has no metadata or if the data provider has to determine it. setReadOnly
Make layer read-only (editing disabled) or not setRefreshOnNofifyMessage
Set the notification message that triggers repaine setRefreshOnNotifyEnabled
Set whether provider notification is connected to triggerRepaint setRenderer
Set renderer which will be invoked to represent this layer. setRenderer3D
Sets 3D renderer for the layer. setScaleBasedVisibility
Sets whether scale based visibility is enabled for the layer. setShortName
Sets the short name of the layer used by QGIS Server to identify the layer. setSimplifyMethod
Set the simplification settings for fast rendering of features setSubLayerVisibility
Set the visibility of the given sublayer name. setSubsetString
Set the string (typically sql) used to define a subset of the layer setTitle
Sets the title of the layer used by QGIS Server in GetCapabilities request. setValid
shortName
Returns the short name of the layer used by QGIS Server to identify the layer. signalsBlocked
simplifyDrawingCanbeApplied
Returns whether the VectorLayer can apply the specified simplification hint simplifyMethod
Returns the simplification settings for fast rendering of features source
Returns the source for the layer. sourceCrs
sourceExtent
sourceName
splitFeatures
Splits features cut by the given line splitParts
Splits parts cut by the given line startEditing
Makes the layer editable. startTimer
storageType
Returns the permanent storage type for this layer as a friendly name. styleManager
Get access to the layer’s style manager. styleURI
Retrieve the style URI for this layer subLayers
Returns the sublayers of this layer. subsetString
Get the string (typically sql) used to define a subset of the layer thread
timerEvent
timestamp
Time stamp of data source in the moment when data/metadata were loaded by provider title
Returns the title of the layer used by QGIS Server in GetCapabilities request. tr
translateFeature
Translates feature by dx, dy triggerRepaint
Will advise the map canvas (and any other interested party) that this layer requires to be repainted. type
Returns the type of the layer. undoStack
Return pointer to layer’s undo stack undoStackStyles
Return pointer to layer’s style undo stack uniqueStringsMatching
Returns unique string values of an attribute which contain a specified subset string. uniqueValues
Calculates a list of unique values contained within an attribute in the layer. updateExpressionField
Changes the expression used to define an expression based (virtual) field updateExtents
Update the extents for the layer. updateFeature
Updates an existing feature
in the layer, replacing the attributes and geometry for the feature with matching QgsFeature.id() with the attributes and geometry fromfeature
.updateFields
Will regenerate the fields property of this layer by obtaining all fields from the dataProvider, joined fields and virtual fields. vectorJoins
wkbType
Returns the WKBType or WKBUnknown in case of error writeCommonStyle
writeCustomProperties
writeLayerXml
Stores state in Dom node writeSld
Writes the symbology of the layer into the document provided in SLD 1.1 format writeStyle
Write just the style information for the layer into the document writeStyleManager
writeSymbology
Write the symbology for the layer into the docment provided. writeXml
Write vector layer specific state to project file Dom node. Attributes
AddToSelection
Cross
EditFailed
EmptyGeometry
FastInsert
FetchFeatureFailed
IntersectSelection
InvalidLayer
Metadata
NoMarker
PluginLayer
RasterLayer
RemoveFromSelection
SemiTransparentCircle
SetSelection
Style
Success
VectorLayer
attributeAdded
Will be emitted, when a new attribute has been added to this vector layer. attributeDeleted
Will be emitted, when an attribute has been deleted from this vector layer. attributeValueChanged
Is emitted whenever an attribute value change is done in the edit buffer. autoRefreshIntervalChanged
Emitted when the auto refresh interval changes. beforeAddingExpressionField
Will be emitted, when an expression field is going to be added to this vector layer. beforeCommitChanges
Is emitted, before changes are committed to the data provider [signal] beforeEditingStarted
Is emitted, before editing on this layer is started [signal] beforeModifiedCheck
Is emitted, when layer is checked for modifications. beforeRemovingExpressionField
Will be emitted, when an expression field is going to be deleted from this vector layer. beforeRollBack
Is emitted, before changes are rolled back [signal] blendModeChanged
Signal emitted when the blend mode is changed, through QgsMapLayer.setBlendMode()
[signal]committedAttributeValuesChanges
This signal is emitted, when attribute value changes are saved to the provider [signal] committedAttributesAdded
This signal is emitted, when attributes are added to the provider [signal] committedAttributesDeleted
This signal is emitted, when attributes are deleted from the provider [signal] committedFeaturesAdded
This signal is emitted, when features are added to the provider [signal] committedFeaturesRemoved
This signal is emitted, when features are deleted from the provider [signal] committedGeometriesChanges
This signal is emitted, when geometry changes are saved to the provider [signal] configChanged
Emitted whenever the configuration is changed. crsChanged
Emit a signal that layer’s CRS has been reset [signal] dataChanged
Data of layer changed [signal] dependenciesChanged
Emitted when dependencies are changed. destroyed
destroyed(self, QObject = None) [signal] displayExpressionChanged
Emitted when the display expression changes editCommandDestroyed
Signal emitted, whan an edit command is destroyed editCommandEnded
Signal emitted, when an edit command successfully ended editCommandStarted
Signal emitted when a new edit command has been started editFormConfigChanged
Will be emitted whenever the edit form configuration of this layer changes. editingStarted
Is emitted, when editing on this layer has started [signal] editingStopped
Is emitted, when edited changes successfully have been written to the data provider [signal] featureAdded
Emitted when a new feature has been added to the layer featureBlendModeChanged
Signal emitted when setFeatureBlendMode() is called [signal] featureDeleted
Emitted when a feature has been deleted. featuresDeleted
Emitted when features have been deleted. geometryChanged
Is emitted whenever a geometry change is done in the edit buffer. labelingFontNotFound
Emitted when the font family defined for labeling layer is not found on system [signal] layerModified
This signal is emitted when modifications has been done on layer [signal] legendChanged
Signal emitted when legend of the layer has changed mapTipTemplateChanged
Emitted when the map tip changes metadataChanged
Emitted when the layer’s metadata is changed. nameChanged
Emitted when the name has been changed objectNameChanged
objectNameChanged(self, str) [signal] opacityChanged
Emitted when the layer’s opacity is changed, where opacity
is a value between 0 (transparent) and 1 (opaque).raiseError
Signals an error related to this vector layer. readCustomSymbology
Signal emitted whenever the symbology (QML-file) for this layer is being read. readOnlyChanged
Emitted when the read only state of this layer is changed. recalculateExtents
This is used to send a request that any mapcanvas using this layer update its extents [signal] renderer3DChanged
Signal emitted when 3D renderer associated with the layer has changed. rendererChanged
Signal emitted when renderer is changed. repaintRequested
By emitting this signal the layer tells that either appearance or content have been changed and any view showing the rendered layer should refresh itself. selectionChanged
This signal is emitted when selection was changed staticMetaObject
statusChanged
Emit a signal with status (e.g. styleChanged
Signal emitted whenever a change affects the layer’s style. symbolFeatureCountMapChanged
Emitted when the feature count for symbols on this layer has been recalculated. updatedFields
Is emitted, whenever the fields available from this layer have been changed. willBeDeleted
Emitted in the destructor when the layer is about to be deleted, but it is still in a perfectly valid state: the last chance for other pieces of code for some cleanup if they use the layer. writeCustomSymbology
Signal emitted whenever the symbology (QML-file) for this layer is being written. -
AddToSelection
= 1¶
-
Cross
= 1¶
-
EditFailed
= 2¶
-
class
EditResult
¶ Bases:
int
-
EmptyGeometry
= 1¶
-
FetchFeatureFailed
= 3¶
-
IntersectSelection
= 2¶
-
InvalidLayer
= 4¶
-
class
LayerOptions
(loadDefaultStyle: bool = True, readExtentFromXml: bool = False)¶ Bases:
sip.wrapper
Constructor for LayerOptions.
QgsVectorLayer.LayerOptions(QgsVectorLayer.LayerOptions)
-
loadDefaultStyle
¶
-
readExtentFromXml
¶
-
-
NoMarker
= 2¶
-
RemoveFromSelection
= 3¶
-
class
SelectBehavior
¶ Bases:
int
-
SemiTransparentCircle
= 0¶
-
SetSelection
= 0¶
-
Success
= 0¶
-
class
VertexMarkerType
¶ Bases:
int
-
actions
(self) → QgsActionManager¶ Get all layer actions defined on this layer.
The pointer which is returned directly points to the actions object which is used by the layer, so any changes are immediately applied.
-
addAttribute
(self, field: QgsField) → bool¶ Add an attribute field (but does not commit it) returns true if the field was added
Note
Calls to addAttribute() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
-
addCurvedPart
(self, ring: QgsCurve) → QgsGeometry.OperationResult¶ Note
available in Python as addCurvedPart
Note
Calls to addPart() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
-
addCurvedRing
(self, ring: QgsCurve) → Tuple[QgsGeometry.OperationResult, int]¶ Adds a ring to polygon/multipolygon features (takes ownership)
Parameters: - ring – ring to add
- featureId – if specified, feature ID for feature ring was added to will be stored in this parameter
Returns: QgsGeometry.OperationResult
- Success
- LayerNotEditable
- AddRingNotInExistingFeature
- InvalidInputGeometryType
- AddRingNotClosed
- AddRingNotValid
- AddRingCrossesExistingRings
Note
available in Python as addCurvedRing
Note
Calls to addRing() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
-
addExpressionField
(self, exp: str, fld: QgsField) → int¶ Add a new field which is calculated by the expression specified
Parameters: - exp – The expression which calculates the field
- fld – The field to calculate
Returns: The index of the new field
New in version 2.9.
-
addFeature
(self, feature: QgsFeature, flags: Union[QgsFeatureSink.Flags, QgsFeatureSink.Flag] = 0) → bool¶
-
addFeatures
(self, features: object, flags: Union[QgsFeatureSink.Flags, QgsFeatureSink.Flag] = 0) → bool¶
-
addJoin
(self, joinInfo: QgsVectorLayerJoinInfo) → bool¶ Joins another vector layer to this layer
Parameters: joinInfo – join object containing join layer id, target and source field Note
since 2.6 returns bool indicating whether the join can be added *
-
addPart
(self, ring: Iterable[QgsPointXY]) → QgsGeometry.OperationResult¶ Adds a new part polygon to a multipart feature
Returns: QgsGeometry.OperationResult - Success
- LayerNotEditable
- SelectionIsEmpty
- SelectionIsGreaterThanOne
- AddPartSelectedGeometryNotFound
- AddPartNotMultiGeometry
- InvalidBaseGeometry
- InvalidInputGeometryType
Note
Calls to addPart() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
-
addPartV2
(self, ring: object) → QgsGeometry.OperationResult¶ Adds a new part polygon to a multipart feature
Returns: QgsGeometry.OperationResult - Success
- LayerNotEditable
- SelectionIsEmpty
- SelectionIsGreaterThanOne
- AddPartSelectedGeometryNotFound
- AddPartNotMultiGeometry
- InvalidBaseGeometry
- InvalidInputGeometryType
Note
available in Python bindings as addPartV2
Note
Calls to addPart() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
-
addRing
(self, ring: Iterable[QgsPointXY]) → Tuple[QgsGeometry.OperationResult, int]¶ Adds a ring to polygon/multipolygon features
Parameters: - ring – ring to add
- featureId – if specified, feature ID for feature ring was added to will be stored in this parameter
Returns: QgsGeometry.OperationResult
- Success
- LayerNotEditable
- AddRingNotInExistingFeature
- InvalidInputGeometryType
- AddRingNotClosed
- AddRingNotValid
- AddRingCrossesExistingRings
Note
Calls to addRing() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
-
addTopologicalPoints
(self, geom: QgsGeometry) → int¶ Adds topological points for every vertex of the geometry.
Parameters: geom – the geometry where each vertex is added to segments of other features Returns: 0 in case of success Note
geom is not going to be modified by the function
Note
Calls to addTopologicalPoints() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
addTopologicalPoints(self, p: QgsPointXY) -> int Adds a vertex to segments which intersect point p but don’t already have a vertex there. If a feature already has a vertex at position p, no additional vertex is inserted. This method is useful for topological editing.
Parameters: p – position of the vertex Returns: 0 in case of success Note
Calls to addTopologicalPoints() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
-
aggregate
(self, aggregate: QgsAggregateCalculator.Aggregate, fieldOrExpression: str, parameters: QgsAggregateCalculator.AggregateParameters = QgsAggregateCalculator.AggregateParameters(), context: QgsExpressionContext = None) → Tuple[Any, bool]¶ Calculates an aggregated value from the layer’s features.
Parameters: - aggregate – aggregate to calculate
- fieldOrExpression – source field or expression to use as basis for aggregated values.
- parameters – parameters controlling aggregate calculation
- context – expression context for expressions and filters
- ok – if specified, will be set to true if aggregate calculation was successful
Returns: calculated aggregate value
New in version 2.16.
-
appendError
()¶
-
attributeAdded
¶ Will be emitted, when a new attribute has been added to this vector layer. Applies only to types QgsFields.OriginEdit, QgsFields.OriginProvider and QgsFields.OriginExpression
Parameters: idx – The index of the new attribute See also
updatedFields()
[signal]
-
attributeAlias
(self, index: int) → str¶ Returns the alias of an attribute name or a null string if there is no alias.
see {attributeDisplayName( int attributeIndex )} which returns the field name if no alias is defined.
-
attributeAliases
(self) → Dict[str, str]¶ Returns a map of field name to attribute alias
-
attributeDeleted
¶ Will be emitted, when an attribute has been deleted from this vector layer. Applies only to types QgsFields.OriginEdit, QgsFields.OriginProvider and QgsFields.OriginExpression
Parameters: idx – The index of the deleted attribute See also
updatedFields()
[signal]
-
attributeDisplayName
(self, index: int) → str¶ Convenience function that returns the attribute alias if defined or the field name else
-
attributeList
(self) → List[int]¶ Returns list of attribute indexes. i.e. a list from 0 … fieldCount() Alias for attributeList()
-
attributeTableConfig
(self) → QgsAttributeTableConfig¶ Get the attribute table configuration object. This defines the appearance of the attribute table.
-
attributeValueChanged
¶ Is emitted whenever an attribute value change is done in the edit buffer. Note that at this point the attribute change is not yet saved to the provider.
Parameters: - fid – The id of the changed feature
- idx – The attribute index of the changed attribute
- value – The new value of the attribute [signal]
-
auxiliaryLayer
(self) → QgsAuxiliaryLayer¶ Returns the current auxiliary layer.
New in version 3.0.
-
beforeAddingExpressionField
¶ Will be emitted, when an expression field is going to be added to this vector layer. Applies only to types QgsFields.OriginExpression
Parameters: fieldName – The name of the attribute to be added [signal]
-
beforeCommitChanges
¶ Is emitted, before changes are committed to the data provider [signal]
-
beforeEditingStarted
¶ Is emitted, before editing on this layer is started [signal]
-
beforeModifiedCheck
¶ Is emitted, when layer is checked for modifications. Use for last-minute additions [signal]
-
beforeRemovingExpressionField
¶ Will be emitted, when an expression field is going to be deleted from this vector layer. Applies only to types QgsFields.OriginExpression
Parameters: idx – The index of the attribute to be deleted [signal]
-
beforeRollBack
¶ Is emitted, before changes are rolled back [signal]
-
beginEditCommand
(self, text: str)¶ Create edit command for undo/redo operations
Parameters: text – text which is to be displayed in undo window
-
boundingBoxOfSelected
(self) → QgsRectangle¶ Returns the bounding box of the selected features. If there is no selection, QgsRectangle(0,0,0,0) is returned
-
capabilitiesString
(self) → str¶ Capabilities for this layer, comma separated and translated.
-
changeAttributeValue
(self, fid: int, field: int, newValue: Any, oldValue: Any = None, skipDefaultValues: bool = False) → bool¶ Changes an attribute value for a feature (but does not immediately commit the changes). The
fid
argument specifies the ID of the feature to be changed.The
field
argument must specify a valid field index for the layer (where an index of 0 corresponds to the first field).The new value to be assigned to the field is given by
newValue
.If a valid QVariant is specified for
oldValue
, it will be used as the field value in the case of an undo operation corresponding to this attribute value change. If an invalid QVariant is used (the default behavior), then the feature’s current value will be automatically retrieved and used. Note that this involves a feature request to the underlying data provider, so it is more efficient to explicitly pass anoldValue
if it is already available.If
skipDefaultValue
is set to true, default field values will not be updated. This can be used to override default field value expressions.Returns true if the feature’s attribute was successfully changed.
Note
Calls to changeAttributeValue() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
See also
See also
See also
See also
-
changeGeometry
(self, fid: int, geometry: QgsGeometry, skipDefaultValue: bool = False) → bool¶ Changes a feature’s
geometry
within the layer’s edit buffer (but does not immediately commit the changes). Thefid
argument specifies the ID of the feature to be changed.If
skipDefaultValue
is set to true, default field values will not be updated. This can be used to override default field value expressions.Returns true if the feature’s geometry was successfully changed.
Note
Calls to changeGeometry() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
See also
See also
See also
See also
-
childEvent
()¶
-
clone
(self) → QgsVectorLayer¶ Returns a new instance equivalent to this one. A new provider is created for the same data source and renderers for features and diagrams are cloned too. Moreover, each attributes (transparency, extent, selected features and so on) are identicals.
Returns: a new layer instance New in version 3.0.
-
commitChanges
(self) → bool¶ Attempts to commit to the underlying data provider any buffered changes made since the last to call to startEditing().
Returns the result of the attempt. If a commit fails (i.e. false is returned), the in-memory changes are left untouched and are not discarded. This allows editing to continue if the commit failed on e.g. a disallowed value in a Postgres database - the user can re-edit and try again.
The commits occur in distinct stages, (add attributes, add features, change attribute values, change geometries, delete features, delete attributes) so if a stage fails, it can be difficult to roll back cleanly. Therefore any error message returned by commitErrors() also includes which stage failed so that the user has some chance of repairing the damage cleanly.
See also
See also
See also
-
commitErrors
(self) → List[str]¶ Returns a list containing any error messages generated when attempting to commit changes to the layer.
See also
-
committedAttributeValuesChanges
¶ This signal is emitted, when attribute value changes are saved to the provider [signal]
-
committedAttributesAdded
¶ This signal is emitted, when attributes are added to the provider [signal]
-
committedAttributesDeleted
¶ This signal is emitted, when attributes are deleted from the provider [signal]
-
committedFeaturesAdded
¶ This signal is emitted, when features are added to the provider [signal]
-
committedFeaturesRemoved
¶ This signal is emitted, when features are deleted from the provider [signal]
-
committedGeometriesChanges
¶ This signal is emitted, when geometry changes are saved to the provider [signal]
-
conditionalStyles
(self) → QgsConditionalLayerStyles¶ Return the conditional styles that are set for this layer. Style information is used to render conditional formatting in the attribute table.
Returns: Return a QgsConditionalLayerStyles object holding the conditional attribute style information. Style information is generic and can be used for anything.
New in version 2.12.
-
connectNotify
()¶
-
constraintDescription
(self, index: int) → str¶ Returns the descriptive name for the constraint expression for a specified field index.
New in version 3.0.
See also
constraints()
See also
See also
-
constraintExpression
(self, index: int) → str¶ Returns the constraint expression for for a specified field index, if set.
New in version 3.0.
See also
See also
See also
-
countSymbolFeatures
(self) → QgsVectorLayerFeatureCounter¶ Count features for symbols. The method will return the feature counter task. You will need to connect to the symbolFeatureCountMapChanged() signal to be notified when the freshly updated feature counts are ready.
Note
If the count features for symbols has been already done a None is returned. If you need to wait for the results, you can call waitForFinished() on the feature counter.
New in version 3.0.
-
createExpressionContext
(self) → QgsExpressionContext¶
-
createExpressionContextScope
(self) → QgsExpressionContextScope¶
-
createMapRenderer
(self, rendererContext: QgsRenderContext) → QgsMapLayerRenderer¶ Return new instance of QgsMapLayerRenderer that will be used for rendering of given context
New in version 2.4.
-
customEvent
()¶
-
dataComment
(self) → str¶ Returns a description for this layer as defined in the data provider.
-
dataProvider
(self) → QgsVectorDataProvider¶
-
defaultValue
(self, index: int, feature: QgsFeature = QgsFeature(), context: QgsExpressionContext = None) → Any¶ Returns the calculated default value for the specified field index. The default value may be taken from a client side default value expression (see setDefaultValueDefinition()) or taken from the underlying data provider.
Parameters: - index – field index
- feature – optional feature to use for default value evaluation. If passed,
then properties from the feature (such as geometry) can be used when calculating the default value. :param context: optional expression context to evaluate expressions again. If not specified, a default context will be created
Returns: calculated default value New in version 3.0.
See also
-
defaultValueDefinition
(self, index: int) → QgsDefaultValue¶ Returns the definition of the expression used when calculating the default value for a field.
Parameters: index – field index Returns: definition of the default value with the expression evaluated when calculating default values for field, or definition with an empty string if no default is set
New in version 3.0.
See also
See also
-
deleteAttribute
(self, attr: int) → bool¶ Deletes an attribute field (but does not commit it).
Note
Calls to deleteAttribute() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
-
deleteAttributes
(self, attrs: Iterable[int]) → bool¶ Deletes a list of attribute fields (but does not commit it)
param attrs the indices of the attributes to delete
Returns: true if at least one attribute has been deleted
-
deleteFeature
(self, fid: int) → bool¶ Deletes a feature from the layer (but does not commit it).
Note
Calls to deleteFeature() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
-
deleteFeatures
(self, fids: object) → bool¶ Deletes a set of features from the layer (but does not commit it)
Parameters: fids – The feature ids to delete Returns: false if the layer is not in edit mode or does not support deleting in case of an active transaction depends on the provider implementation
Note
Calls to deleteFeatures() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
-
deleteSelectedFeatures
(self) → Tuple[bool, int]¶ Deletes the selected features
Returns: true in case of success and false otherwise
-
deleteStyleFromDatabase
(self, styleId: str) → Tuple[bool, str]¶ Delete a style from the database
Parameters: - styleId – the provider’s layer_styles table id of the style to delete
- msgError – reference to string that will be updated with any error messages
Returns: true in case of success
New in version 3.0.
-
deleteVertex
(self, featureId: int, vertex: int) → QgsVectorLayer.EditResult¶ Deletes a vertex from a feature.
Parameters: - featureId – ID of feature to remove vertex from
- vertex – index of vertex to delete
New in version 2.14.
Note
Calls to deleteVertex() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
-
dependencies
(self) → Set[QgsMapLayerDependency]¶ Gets the list of dependencies. This includes data dependencies set by the user (
setDataDependencies()
) as well as dependencies given by the providerReturns: a set of QgsMapLayerDependency
New in version 3.0.
-
deselect
(self, featureId: int)¶ Deselect feature by its ID
Parameters: featureId – The id of the feature to deselect See also
deselect(self, featureIds: object) Deselect features by their ID
Parameters: featureIds – The ids of the features to deselect See also
-
destroyEditCommand
(self)¶ Destroy active command and reverts all changes in it
-
diagramLayerSettings
(self) → QgsDiagramLayerSettings¶
-
diagramRenderer
(self) → QgsDiagramRenderer¶
-
diagramsEnabled
(self) → bool¶ Returns whether the layer contains diagrams which are enabled and should be drawn.
Returns: true if layer contains enabled diagrams New in version 2.9.
-
disconnectNotify
()¶
-
displayExpression
(self) → str¶ Get the preview expression, used to create a human readable preview string. Uses
QgsExpression
Returns: The expression which will be used to preview features for this layer
-
displayExpressionChanged
¶ Emitted when the display expression changes
New in version 3.0: [signal]
-
displayField
(self) → str¶ This is a shorthand for accessing the displayExpression if it is a simple field. If the displayExpression is more complex than a simple field, a null string will be returned.
See also
-
drawVertexMarker
(x: float, y: float, p: QPainter, type: QgsVectorLayer.VertexMarkerType, vertexSize: int)¶ Draws a vertex symbol at (screen) coordinates x, y. (Useful to assist vertex editing.)
-
editBuffer
(self) → QgsVectorLayerEditBuffer¶ Buffer with uncommitted editing operations. Only valid after editing has been turned on.
-
editCommandDestroyed
¶ Signal emitted, whan an edit command is destroyed
Note
This is not a rollback, it is only related to the current edit command. See beforeRollBack() [signal]
-
editCommandEnded
¶ Signal emitted, when an edit command successfully ended
Note
This does not mean it is also committed, only that it is written to the edit buffer. See beforeCommitChanges() [signal]
-
editCommandStarted
¶ Signal emitted when a new edit command has been started
Parameters: text – Description for this edit command [signal]
-
editFormConfig
(self) → QgsEditFormConfig¶ Get the configuration of the form used to represent this vector layer. This is a writable configuration that can directly be changed in place.
Returns: The configuration of this layers’ form New in version 2.14.
-
editFormConfigChanged
¶ Will be emitted whenever the edit form configuration of this layer changes.
New in version 3.0: [signal]
-
editingStarted
¶ Is emitted, when editing on this layer has started [signal]
-
editingStopped
¶ Is emitted, when edited changes successfully have been written to the data provider [signal]
-
editorWidgetSetup
(self, index: int) → QgsEditorWidgetSetup¶ The editor widget setup defines which QgsFieldFormatter and editor widget will be used for the field at index.
New in version 3.0.
-
endEditCommand
(self)¶ Finish edit command and add it to undo/redo stack
-
excludeAttributesWfs
(self) → Set[str]¶ A set of attributes that are not advertised in WFS requests with QGIS server.
-
excludeAttributesWms
(self) → Set[str]¶ A set of attributes that are not advertised in WMS requests with QGIS server.
-
expressionField
(self, index: int) → str¶ Returns the expression used for a given expression field
Parameters: index – An index of an epxression based (virtual) field Returns: The expression for the field at index New in version 2.9.
-
extent
(self) → QgsRectangle¶
-
featureAdded
¶ Emitted when a new feature has been added to the layer
Parameters: fid – The id of the new feature [signal]
-
featureBlendMode
(self) → QPainter.CompositionMode¶ Returns the current blending mode for features
-
featureBlendModeChanged
¶ Signal emitted when setFeatureBlendMode() is called [signal]
-
featureCount
(self, legendKey: str) → int¶ Number of features rendered with specified legend key. Features must be first calculated by countSymbolFeatures()
Returns: number of features rendered by symbol or -1 if failed or counts are not available featureCount(self) -> int Returns feature count including changes which have not yet been committed If you need only the count of committed features call this method on this layer’s provider.
-
featureDeleted
¶ Emitted when a feature has been deleted.
If you do expensive operations in a slot connected to this, you should prefer to use featuresDeleted( const :py:class:`QgsFeatureIds`& ).
Parameters: fid – The id of the feature which has been deleted [signal]
-
featuresDeleted
¶ Emitted when features have been deleted.
If features are deleted within an edit command, this will only be emitted once at the end to allow connected slots to minimize the overhead. If features are deleted outside of an edit command, this signal will be emitted once per feature.
Parameters: fids – The feature ids that have been deleted. [signal]
-
fieldConstraints
(self, fieldIndex: int) → QgsFieldConstraints.Constraints¶ Returns any constraints which are present for a specified field index. These constraints may be inherited from the layer’s data provider or may be set manually on the vector layer from within QGIS.
New in version 3.0.
See also
-
fieldConstraintsAndStrength
(self, fieldIndex: int) → object¶ Returns a map of constraint with their strength for a specific field of the layer.
Parameters: fieldIndex – field index New in version 3.0.
-
fields
(self) → QgsFields¶ Returns the list of fields of this layer. This also includes fields which have not yet been saved to the provider.
Returns: A list of fields
-
geometryChanged
¶ Is emitted whenever a geometry change is done in the edit buffer. Note that at this point the geometry change is not yet saved to the provider.
Parameters: - fid – The id of the changed feature
- geometry – The new geometry [signal]
-
geometryType
(self) → QgsWkbTypes.GeometryType¶ Returns point, line or polygon
-
getDoubleValues
(self, fieldOrExpression: str, selectedOnly: bool = False, feedback: QgsFeedback = None) → Tuple[List[float], bool, int]¶ Fetches all double values from a specified field name or expression. Null values or invalid expression results are skipped.
Parameters: - fieldOrExpression – field name or an expression string evaluating to a double value
- ok – will be set to false if field or expression is invalid, otherwise true
- selectedOnly – set to true to get values from selected features only
- nullCount – optional pointer to integer to store number of null values encountered in
- feedback – optional feedback object to allow cancelation
Returns: list of fetched values
New in version 2.9.
See also
-
getFeature
(self, fid: int) → QgsFeature¶ Query the layer for the feature with the given id. If there is no such feature, the returned feature will be invalid.
-
getFeatures
(self, request: QgsFeatureRequest = QgsFeatureRequest()) → QgsFeatureIterator¶ Query the layer for features specified in request.
Parameters: request – feature request describing parameters of features to return Returns: iterator for matching features from provider getFeatures(self, expression: str) -> QgsFeatureIterator Query the layer for features matching a given expression.
getFeatures(self, fids: object) -> QgsFeatureIterator Query the layer for the features with the given ids.
getFeatures(self, rectangle: QgsRectangle) -> QgsFeatureIterator Query the layer for the features which intersect the specified rectangle.
-
getSelectedFeatures
(self, request: QgsFeatureRequest = QgsFeatureRequest()) → QgsFeatureIterator¶ Get an iterator of the selected features
Parameters: request – You may specify a request, e.g. to limit the set of requested attributes. Any filter on the request will be discarded.
Returns: Iterator over the selected features See also
See also
-
getStyleFromDatabase
(self, styleId: str) → Tuple[str, str]¶ Will return the named style corresponding to style id provided
-
getValues
(self, fieldOrExpression: str, selectedOnly: bool = False, feedback: QgsFeedback = None) → Tuple[List[Any], bool]¶ Fetches all values from a specified field name or expression.
Parameters: - fieldOrExpression – field name or an expression string
- ok – will be set to false if field or expression is invalid, otherwise true
- selectedOnly – set to true to get values from selected features only
- feedback – optional feedback object to allow cancelation
Returns: list of fetched values
New in version 2.9.
See also
-
hasDependencyCycle
()¶
-
htmlMetadata
(self) → str¶
-
insertVertex
(self, x: float, y: float, atFeatureId: int, beforeVertex: int) → bool¶ Insert a new vertex before the given vertex number, in the given ring, item (first number is index 0), and feature Not meaningful for Point geometries
Note
Calls to insertVertex() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
insertVertex(self, point: QgsPoint, atFeatureId: int, beforeVertex: int) -> bool Insert a new vertex before the given vertex number, in the given ring, item (first number is index 0), and feature Not meaningful for Point geometries
Note
Calls to insertVertex() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
-
invertSelection
(self)¶ Select not selected features and deselect selected ones
-
invertSelectionInRectangle
(self, rect: QgsRectangle)¶ Invert selection of features found within the search rectangle (in layer’s coordinates)
Parameters: rect – The rectangle in which the selection of features will be inverted See also
-
isAuxiliaryField
(self, index: int) → Tuple[bool, int]¶ Returns true if the field comes from the auxiliary layer, false otherwise.
New in version 3.0.
-
isEditCommandActive
(self) → bool¶ Test if an edit command is active
New in version 3.0.
-
isEditable
(self) → bool¶ Returns true if the provider is in editing mode
-
isModified
(self) → bool¶ Returns true if the provider has been modified since the last commit
-
isSignalConnected
()¶
-
isSpatial
(self) → bool¶ Returns true if this is a geometry layer and false in case of NoGeometry (table only) or UnknownGeometry
-
joinBuffer
(self) → QgsVectorLayerJoinBuffer¶ Accessor to the join buffer object
New in version 2.14.7.
-
labeling
(self) → QgsAbstractVectorLayerLabeling¶ Access to labeling configuration. May be null if labeling is not used.
New in version 3.0.
-
labelingFontNotFound
¶ Emitted when the font family defined for labeling layer is not found on system [signal]
-
labelsEnabled
(self) → bool¶ Returns whether the layer contains labels which are enabled and should be drawn.
Returns: true if layer contains enabled labels New in version 2.9.
-
layerModified
¶ This signal is emitted when modifications has been done on layer [signal]
-
listStylesInDatabase
(self) → Tuple[int, List[str], List[str], List[str], str]¶ Lists all the style in db split into related to the layer and not related to
Parameters: - ids – the list in which will be stored the style db ids
- names – the list in which will be stored the style names
- descriptions – the list in which will be stored the style descriptions
- msgError –
Returns: the number of styles related to current layer
-
loadAuxiliaryLayer
(self, storage: QgsAuxiliaryStorage, key: str = '') → bool¶ Loads the auxiliary layer for this vector layer. If there’s no corresponding table in the database, then nothing happens and false is returned. The key is optional because if this layer has been read from a XML document, then the key read in this document is used by default.
Parameters: - storage – The auxiliary storage where to look for the table
- key – The key to use for joining.
Returns: true if the auxiliary layer is well loaded, false otherwise
New in version 3.0.
-
loadNamedStyle
(self, theURI: str, loadFromLocalDb: bool) → Tuple[str, bool]¶ Load a named style from file/local db/datasource db
Parameters: - theURI – the URI of the style or the URI of the layer
- resultFlag – will be set to true if a named style is correctly loaded
- loadFromLocalDb – if true forces to load from local db instead of datasource one
loadNamedStyle(self, theURI: str) -> Tuple[str, bool] Calls loadNamedStyle( theURI, resultFlag, false ); Retained for backward compatibility
-
mapTipTemplate
(self) → str¶ The mapTip is a pretty, html representation for feature information.
It may also contain embedded expressions.
New in version 3.0.
-
mapTipTemplateChanged
¶ Emitted when the map tip changes
New in version 3.0: [signal]
-
maximumValue
(self, index: int) → Any¶ Returns the maximum value for an attribute column or an invalid variant in case of error. Note that in some circumstances when unsaved changes are present for the layer then the returned value may be outdated (for instance when the attribute value in a saved feature has been changed inside the edit buffer then the previous saved value may be returned as the maximum).
See also
See also
-
minimumValue
(self, index: int) → Any¶ Returns the minimum value for an attribute column or an invalid variant in case of error. Note that in some circumstances when unsaved changes are present for the layer then the returned value may be outdated (for instance when the attribute value in a saved feature has been changed inside the edit buffer then the previous saved value may be returned as the minimum).
See also
See also
-
modifySelection
(self, selectIds: object, deselectIds: object)¶ Modifies the current selection on this layer
Parameters: - selectIds – Select these ids
- deselectIds – Deselect these ids
See also
See also
See also
See also
See also
-
moveVertex
(self, x: float, y: float, atFeatureId: int, atVertex: int) → bool¶ Moves the vertex at the given position number, ring and item (first number is index 0), and feature to the given coordinates
Note
Calls to moveVertex() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
-
moveVertexV2
(self, p: QgsPoint, atFeatureId: int, atVertex: int) → bool¶ Moves the vertex at the given position number, ring and item (first number is index 0), and feature to the given coordinates
Note
available in Python as moveVertexV2
Note
Calls to moveVertex() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
-
opacity
(self) → float¶ Returns the opacity for the vector layer, where opacity is a value between 0 (totally transparent) and 1.0 (fully opaque).
See also
See also
New in version 3.0.
-
opacityChanged
¶ Emitted when the layer’s opacity is changed, where
opacity
is a value between 0 (transparent) and 1 (opaque).New in version 3.0.
See also
See also
opacity()
[signal]
-
pendingAllAttributesList
(self) → List[int]¶ Returns list of attribute indexes. i.e. a list from 0 … fieldCount() Alias for attributeList()
-
pendingFeatureCount
(self) → int¶ Returns feature count including changes which have not yet been committed Alias for featureCount()
-
pendingFields
(self) → QgsFields¶ Returns the list of fields of this layer. This also includes fields which have not yet been saved to the provider. Alias for fields()
Returns: A list of fields
-
pendingPkAttributesList
(self) → List[int]¶ Returns list of attributes making up the primary key Alias for pkAttributeList()
-
pkAttributeList
(self) → List[int]¶ Returns list of attributes making up the primary key
-
providerType
(self) → str¶ Return the provider type for this layer
-
raiseError
¶ Signals an error related to this vector layer. [signal]
-
readCommonStyle
()¶
-
readCustomProperties
()¶
-
readCustomSymbology
¶ Signal emitted whenever the symbology (QML-file) for this layer is being read. If there is custom style information saved in the file, you can connect to this signal and update the layer style accordingly.
Parameters: - element – The XML layer style element.
- errorMessage – Write error messages into this string. [signal]
-
readExtentFromXml
(self) → bool¶ Returns true if the extent is read from the XML document when data source has no metadata, false if it’s the data provider which determines it.
New in version 3.0.
-
readOnlyChanged
¶ Emitted when the read only state of this layer is changed. Only applies to manually set readonly state, not to the edit mode.
New in version 3.0: [signal]
-
readSld
(self, node: QDomNode, errorMessage: str) → bool¶
-
readStyle
(self, node: QDomNode, errorMessage: str, context: QgsReadWriteContext) → bool¶ Read the style for the current layer from the Dom node supplied.
Parameters: - node – node that will contain the style definition for this layer.
- errorMessage – reference to string that will be updated with any error messages
- context – reading context (used for transform from relative to absolute paths)
Returns: true in case of success.
-
readStyleManager
()¶
-
readSymbology
(self, layerNode: QDomNode, errorMessage: str, context: QgsReadWriteContext) → bool¶ Read the symbology for the current layer from the Dom node supplied.
Parameters: - layerNode – node that will contain the symbology definition for this layer.
- errorMessage – reference to string that will be updated with any error messages
- context – reading context (used for transform from relative to absolute paths)
Returns: true in case of success.
-
readXml
(self, layer_node: QDomNode, context: QgsReadWriteContext) → bool¶ Reads vector layer specific state from project file Dom node.
Note
Called by
QgsMapLayer.readXml()
-
receivers
()¶
-
referencingRelations
(self, idx: int) → List[QgsRelation]¶ Get relations, where the foreign key is on this layer
Parameters: idx – Only get relations, where idx forms part of the foreign key Returns: A list of relations
-
reload
(self)¶ Synchronises with changes in the datasource
-
removeExpressionField
(self, index: int)¶ Remove an expression field
Parameters: index – The index of the field New in version 2.6.
-
removeFieldAlias
(self, index: int)¶ Removes an alias (a display name) for attributes to display in dialogs
New in version 3.0.
-
removeFieldConstraint
(self, index: int, constraint: QgsFieldConstraints.Constraint)¶ Removes a constraint for a specified field index. Any constraints inherited from the layer’s data provider will be kept intact and cannot be removed.
New in version 3.0.
See also
See also
-
removeJoin
(self, joinLayerId: str) → bool¶ Removes a vector layer join
Returns: true if join was found and successfully removed *
-
removeSelection
(self)¶ Clear selection
See also
-
renameAttribute
(self, index: int, newName: str) → bool¶ Renames an attribute field (but does not commit it).
Parameters: - index – attribute index
- newName – new name of field
New in version 2.16.
Note
Calls to renameAttribute() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
-
renderer
(self) → QgsFeatureRenderer¶ Return renderer.
-
resolveReferences
(self, project: QgsProject)¶ Resolve references to other layers (kept as layer IDs after reading XML) into layer objects.
New in version 3.0.
-
rollBack
(self, deleteBuffer: bool = True) → bool¶ Stops a current editing operation and discards any uncommitted edits.
If
deleteBuffer
is true the editing buffer will be completely deleted (the default behavior).See also
See also
-
saveStyleToDatabase
(self, name: str, description: str, useAsDefault: bool, uiFileContent: str) → str¶ Save named and sld style of the layer to the style table in the db.
Parameters: - name –
- description –
- useAsDefault –
- uiFileContent –
- msgError –
-
select
(self, featureId: int)¶ Select feature by its ID
Parameters: featureId – The id of the feature to select See also
select(self, featureIds: object) Select features by their ID
Parameters: featureIds – The ids of the features to select See also
-
selectAll
(self)¶ Select all the features
-
selectByExpression
(self, expression: str, behavior: QgsVectorLayer.SelectBehavior = QgsVectorLayer.SetSelection)¶ Select matching features using an expression.
Parameters: - expression – expression to evaluate to select features
- behavior – selection type, allows adding to current selection, removing
from selection, etc.
New in version 2.16.
See also
See also
-
selectByIds
(self, ids: object, behavior: QgsVectorLayer.SelectBehavior = QgsVectorLayer.SetSelection)¶ Select matching features using a list of feature IDs. Will emit the selectionChanged() signal with the clearAndSelect flag set.
Parameters: - ids – feature IDs to select
- behavior – selection type, allows adding to current selection, removing
from selection, etc.
New in version 2.16.
See also
See also
-
selectByRect
(self, rect: QgsRectangle, behavior: QgsVectorLayer.SelectBehavior = QgsVectorLayer.SetSelection)¶ Select features found within the search rectangle (in layer’s coordinates)
Parameters: - rect – search rectangle
- behavior – selection type, allows adding to current selection, removing
from selection, etc.
See also
See also
See also
-
selectedFeatureCount
(self) → int¶ The number of features that are selected in this layer
Returns: See description
-
selectedFeatureIds
(self) → object¶ Return reference to identifiers of selected features
Returns: A list of QgsFeatureId
See also
-
selectedFeatures
(self) → object¶ Get a copy of the user-selected features
Returns: A list of QgsFeature
See also
See also
-
selectionChanged
¶ This signal is emitted when selection was changed
Parameters: - selected – Newly selected feature ids
- deselected – Ids of all features which have previously been selected but are not any more
- clearAndSelect – In case this is set to true, the old selection was dismissed and the new selection corresponds to selected [signal]
-
sender
()¶
-
senderSignalIndex
()¶
-
setAttributeTableConfig
(self, attributeTableConfig: QgsAttributeTableConfig)¶ Set the attribute table configuration object. This defines the appearance of the attribute table.
-
setAuxiliaryLayer
(self, layer: QgsAuxiliaryLayer = None)¶ Sets the current auxiliary layer. The auxiliary layer is automatically put in editable mode and fields are updated. Moreover, a join is created between the current layer and the auxiliary layer. Ownership is transferred.
New in version 3.0.
-
setConstraintExpression
(self, index: int, expression: str, description: str = '')¶ Set the constraint expression for the specified field index. An optional descriptive name for the constraint can also be set. Setting an empty expression will clear any existing expression constraint.
New in version 3.0.
See also
See also
See also
constraints()
-
setCoordinateSystem
(self)¶ Setup the coordinate system transformation for the layer
-
setDataSource
(self, dataSource: str, baseName: str, provider: str, loadDefaultStyleFlag: bool = False)¶ Update the data source of the layer. The layer’s renderer and legend will be preserved only if the geometry type of the new data source matches the current geometry type of the layer.
Parameters: - dataSource – new layer data source
- baseName – base name of the layer
- provider – provider string
- loadDefaultStyleFlag – set to true to reset the layer’s style to the default for the
data source
New in version 2.10.
-
setDefaultValueDefinition
(self, index: int, definition: QgsDefaultValue)¶ Sets the definition of the expression to use when calculating the default value for a field.
Parameters: - index – field index
- definition – default value definition to use and evaluate
when calculating default values for field. Pass an empty expression to clear the default.
New in version 3.0.
See also
See also
-
setDependencies
(self, layers: Iterable[QgsMapLayerDependency]) → bool¶ Sets the list of dependencies.
See also
Parameters: layers – set of QgsMapLayerDependency
. Only user-defined dependencies will be addedReturns: false if a dependency cycle has been detected New in version 3.0.
-
setDiagramLayerSettings
(self, s: QgsDiagramLayerSettings)¶
-
setDiagramRenderer
(self, r: QgsDiagramRenderer)¶ Sets diagram rendering object (takes ownership)
-
setDisplayExpression
(self, displayExpression: str)¶ Set the preview expression, used to create a human readable preview string. Used e.g. in the attribute table feature list. Uses
QgsExpression
.Parameters: displayExpression – The expression which will be used to preview features for this layer
-
setEditFormConfig
(self, editFormConfig: QgsEditFormConfig)¶ Get the configuration of the form used to represent this vector layer. This is a writable configuration that can directly be changed in place.
Returns: The configuration of this layers’ form New in version 3.0.
-
setEditorWidgetSetup
(self, index: int, setup: QgsEditorWidgetSetup)¶ copydoc editorWidgetSetup
-
setError
()¶
-
setExcludeAttributesWfs
(self, att: Iterable[str])¶ A set of attributes that are not advertised in WFS requests with QGIS server.
-
setExcludeAttributesWms
(self, att: Iterable[str])¶ A set of attributes that are not advertised in WMS requests with QGIS server.
-
setExtent
(self, rect: QgsRectangle)¶ Set the extent
-
setFeatureBlendMode
(self, blendMode: QPainter.CompositionMode)¶ Set the blending mode used for rendering each feature
-
setFieldAlias
(self, index: int, aliasString: str)¶ Sets an alias (a display name) for attributes to display in dialogs
New in version 3.0.
-
setFieldConstraint
(self, index: int, constraint: QgsFieldConstraints.Constraint, strength: QgsFieldConstraints.ConstraintStrength = QgsFieldConstraints.ConstraintStrengthHard)¶ Sets a constraint for a specified field index. Any constraints inherited from the layer’s data provider will be kept intact and cannot be modified. Ie, calling this method only allows for new constraints to be added on top of the existing provider constraints.
New in version 3.0.
See also
See also
-
setLabeling
(self, labeling: QgsAbstractVectorLayerLabeling)¶ Set labeling configuration. Takes ownership of the object.
New in version 3.0.
-
setMapTipTemplate
(self, mapTipTemplate: str)¶ The mapTip is a pretty, html representation for feature information.
It may also contain embedded expressions.
New in version 3.0.
-
setOpacity
(self, opacity: float)¶ Sets the
opacity
for the vector layer, whereopacity
is a value between 0 (totally transparent) and 1.0 (fully opaque).See also
See also
New in version 3.0.
-
setProviderEncoding
(self, encoding: str)¶ Sets the textencoding of the data provider
-
setReadExtentFromXml
(self, readExtentFromXml: bool)¶ Flag allowing to indicate if the extent has to be read from the XML document when data source has no metadata or if the data provider has to determine it.
New in version 3.0.
-
setReadOnly
(self, readonly: bool = True) → bool¶ Make layer read-only (editing disabled) or not
Returns: false if the layer is in editing yet
-
setRenderer
(self, r: QgsFeatureRenderer)¶ Set renderer which will be invoked to represent this layer. Ownership is transferred.
-
setSimplifyMethod
(self, simplifyMethod: QgsVectorSimplifyMethod)¶ Set the simplification settings for fast rendering of features
New in version 2.2.
-
setSubsetString
(self, subset: str) → bool¶ Set the string (typically sql) used to define a subset of the layer
Parameters: subset – The subset string. This may be the where clause of a sql statement or other definition string specific to the underlying dataprovider and data store.
Returns: true, when setting the subset string was successful, false otherwise
-
setValid
()¶
-
simplifyDrawingCanbeApplied
(self, renderContext: QgsRenderContext, simplifyHint: QgsVectorSimplifyMethod.SimplifyHint) → bool¶ Returns whether the VectorLayer can apply the specified simplification hint
Note
Do not use in 3rd party code - may be removed in future version!
New in version 2.2.
-
simplifyMethod
(self) → QgsVectorSimplifyMethod¶ Returns the simplification settings for fast rendering of features
New in version 2.2.
-
sourceCrs
(self) → QgsCoordinateReferenceSystem¶
-
sourceExtent
(self) → QgsRectangle¶
-
sourceName
(self) → str¶
-
splitFeatures
(self, splitLine: Iterable[QgsPointXY], topologicalEditing: bool = False) → QgsGeometry.OperationResult¶ Splits features cut by the given line
Parameters: - splitLine – line that splits the layer features
- topologicalEditing – true if topological editing is enabled
Returns: QgsGeometry.OperationResult
- Success
- NothingHappened
- LayerNotEditable
- InvalidInputGeometryType
- InvalidBaseGeometry
- GeometryEngineError
- SplitCannotSplitPoint
Note
Calls to splitFeatures() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
-
splitParts
(self, splitLine: Iterable[QgsPointXY], topologicalEditing: bool = False) → QgsGeometry.OperationResult¶ Splits parts cut by the given line
Parameters: - splitLine – line that splits the layer features
- topologicalEditing – true if topological editing is enabled
Returns: QgsGeometry.OperationResult
- Success
- NothingHappened
- LayerNotEditable
- InvalidInputGeometryType
- InvalidBaseGeometry
- GeometryEngineError
- SplitCannotSplitPoint
Note
Calls to splitParts() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
-
startEditing
(self) → bool¶ Makes the layer editable.
This starts an edit session on this layer. Changes made in this edit session will not be made persistent until commitChanges() is called, and can be reverted by calling rollBack().
Returns true if the layer was successfully made editable, or false if the operation failed (e.g. due to an underlying read-only data source, or lack of edit support by the backend data provider).
See also
See also
-
storageType
(self) → str¶ Returns the permanent storage type for this layer as a friendly name. This is obtained from the data provider and does not follow any standard.
-
subsetString
(self) → str¶ Get the string (typically sql) used to define a subset of the layer
Returns: The subset string or null QString if not implemented by the provider
-
symbolFeatureCountMapChanged
¶ Emitted when the feature count for symbols on this layer has been recalculated.
New in version 3.0: [signal]
-
timerEvent
()¶
-
translateFeature
(self, featureId: int, dx: float, dy: float) → int¶ Translates feature by dx, dy
Parameters: - featureId – id of the feature to translate
- dx – translation of x-coordinate
- dy – translation of y-coordinate
Returns: 0 in case of success
Note
Calls to translateFeature() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
-
uniqueStringsMatching
(self, index: int, substring: str, limit: int = -1, feedback: QgsFeedback = None) → List[str]¶ Returns unique string values of an attribute which contain a specified subset string. Subset matching is done in a case-insensitive manner. Note that in some circumstances when unsaved changes are present for the layer then the returned list may contain outdated values (for instance when the attribute value in a saved feature has been changed inside the edit buffer then the previous saved value will be included in the returned list).
Parameters: - index – column index for attribute
- substring – substring to match (case insensitive)
- limit – maxmum number of the values to return, or -1 to return all unique values
- feedback – optional feedback object for canceling request
Returns: list of unique strings containing substring
-
uniqueValues
(self, fieldIndex: int, limit: int = -1) → Set[Any]¶ Calculates a list of unique values contained within an attribute in the layer. Note that in some circumstances when unsaved changes are present for the layer then the returned list may contain outdated values (for instance when the attribute value in a saved feature has been changed inside the edit buffer then the previous saved value will be included in the returned list).
Parameters: - fieldIndex – column index for attribute
- limit – maximum number of values to return (or -1 if unlimited)
See also
See also
-
updateExpressionField
(self, index: int, exp: str)¶ Changes the expression used to define an expression based (virtual) field
Parameters: - index – The index of the expression to change
- exp – The new expression to set
New in version 2.9.
-
updateExtents
(self, force: bool = False)¶ Update the extents for the layer. This is necessary if features are added/deleted or the layer has been subsetted.
Parameters: force – true to update layer extent even if it’s read from xml by default, false otherwise
-
updateFeature
(self, feature: QgsFeature, skipDefaultValues: bool = False) → bool¶ Updates an existing
feature
in the layer, replacing the attributes and geometry for the feature with matching QgsFeature.id() with the attributes and geometry fromfeature
. Changes are not immediately committed to the layer.If
skipDefaultValue
is set to true, default field values will not be updated. This can be used to override default field value expressions.Returns true if the feature’s attribute was successfully changed.
Note
Calls to updateFeature() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().
Warning
This method needs to query the underlying data provider to fetch the feature with matching QgsFeature.id() on every call. Depending on the underlying data source this can be slow to execute. Consider using the more efficient changeAttributeValue() or changeGeometry() methods instead.
See also
See also
See also
See also
-
updateFields
(self)¶ Will regenerate the fields property of this layer by obtaining all fields from the dataProvider, joined fields and virtual fields. It will also take any changes made to default values into consideration.
Note
Unless the fields on the provider have directly been modified, there is no reason to call this method.
-
updatedFields
¶ Is emitted, whenever the fields available from this layer have been changed. This can be due to manually adding attributes or due to a join. [signal]
-
vectorJoins
(self) → List[QgsVectorLayerJoinInfo]¶
-
wkbType
(self) → QgsWkbTypes.Type¶ Returns the WKBType or WKBUnknown in case of error
-
writeCommonStyle
()¶
-
writeCustomProperties
()¶
-
writeCustomSymbology
¶ Signal emitted whenever the symbology (QML-file) for this layer is being written. If there is custom style information you want to save to the file, you can connect to this signal and update the element accordingly.
Parameters: - element – The XML element where you can add additional style information to.
- doc – The XML document that you can use to create new XML nodes.
- errorMessage – Write error messages into this string. [signal]
-
writeSld
(self, node: QDomNode, doc: QDomDocument, errorMessage: str, props: Dict[str, str] = {}) → bool¶ Writes the symbology of the layer into the document provided in SLD 1.1 format
Parameters: - node – the node that will have the style element added to it.
- doc – the document that will have the QDomNode added.
- errorMessage – reference to string that will be updated with any error messages
- props – a open ended set of properties that can drive/inform the SLD encoding
Returns: true in case of success
-
writeStyle
(self, node: QDomNode, doc: QDomDocument, errorMessage: str, context: QgsReadWriteContext) → bool¶ Write just the style information for the layer into the document
Parameters: - node – the node that will have the style element added to it.
- doc – the document that will have the QDomNode added.
- errorMessage – reference to string that will be updated with any error messages
- context – writing context (used for transform from absolute to relative paths)
Returns: true in case of success.
-
writeStyleManager
()¶
-
writeSymbology
(self, node: QDomNode, doc: QDomDocument, errorMessage: str, context: QgsReadWriteContext) → bool¶ Write the symbology for the layer into the docment provided.
Parameters: - node – the node that will have the style element added to it.
- doc – the document that will have the QDomNode added.
- errorMessage – reference to string that will be updated with any error messages
- context – writing context (used for transform from absolute to relative paths)
Returns: true in case of success.
-
writeXml
(self, layer_node: QDomNode, doc: QDomDocument, context: QgsReadWriteContext) → bool¶ Write vector layer specific state to project file Dom node.
Note
Called by
QgsMapLayer.writeXml()