Subgroup: Project

Class: QgsProject

class qgis.core.QgsProject(parent: QObject = None)

Bases: PyQt5.QtCore.QObject, qgis._core.QgsExpressionContextGenerator

Create a new QgsProject.

Most of the time you want to use QgsProject.instance() instead as many components of QGIS work with the singleton.

Reads and writes project states.

note

Has two general kinds of state to make persistent. (I.e., to read and write.) First, QGIS proprietary information. Second plug-in information.

A singleton since there shall only be one active project at a time; and provides canonical location for plug-ins and main app to find/set properties.

Methods

absoluteFilePath Returns full absolute path to the project file if the project is stored in a file system - derived from fileName().
addMapLayer Add a layer to the map of loaded layers.
addMapLayers Add a list of layers to the map of loaded layers.
annotationManager Returns pointer to the project’s annotation manager.
areaUnits Convenience function to query default area measurement units for project.
autoTransaction Transactional editing means that on supported datasources (postgres databases) the edit state of all tables that originate from the same database are synchronized and executed in a server side transaction.
auxiliaryStorage Returns the current auxiliary storage.
avoidIntersectionsLayers A list of layers with which intersections should be avoided.
baseName Returns the base name of the project file without the path and without extension - derived from fileName().
childEvent
clear Clear the project - removes all settings and resets it back to an empty, default state.
connectNotify
count Returns the number of registered layers.
createEmbeddedGroup Create layer group instance defined in an arbitrary project file.
createExpressionContext
crs Returns the project’s native coordinate reference system.
customEvent
customVariables A map of custom project variables.
defaultCrsForNewLayers Returns the default CRS for new layers based on the settings and the current project CRS
disconnectNotify
distanceUnits Convenience function to query default distance measurement units for project.
dumpProperties
ellipsoid Returns a proj string representing the project’s ellipsoid setting, e.
entryList Return keys with values – do not return keys that contain other keys
error Return error message from previous read/write
evaluateDefaultValues Should default values be evaluated on provider side when requested and not when committed.
fileInfo Returns QFileInfo object for the project’s associated file.
fileName Returns the project’s file name.
homePath Returns the project’s home path.
instance Returns the QgsProject singleton instance
isDirty Returns true if the project has been modified since the last write()
isSignalConnected
isZipped Returns true if the project comes from a zip archive, false otherwise.
labelingEngineSettings Returns project’s global labeling engine settings
lastModified Returns last modified time of the project file as returned by the file system (or other project storage).
layerIsEmbedded Returns project file path if layer is embedded from other project file.
layerStore Returns a pointer to the project’s internal layer store.
layerTreeRegistryBridge Return pointer to the helper class that synchronizes map layer registry with layer tree
layerTreeRoot Return pointer to the root (invisible) node of the project’s layer tree
layoutManager Returns the project’s layout manager, which manages compositions within the project.
mapLayer Retrieve a pointer to a registered layer by layer ID.
mapLayers Returns a map of all registered layers by layer ID.
mapLayersByName Retrieve a list of matching registered layers by layer name.
mapThemeCollection Returns pointer to the project’s map theme collection.
metadata Returns a reference to the project’s metadata store.
nonIdentifiableLayers Get the list of layers which currently should not be taken into account on map identification
pathResolver Return path resolver object with considering whether the project uses absolute or relative paths and using current project’s path.
presetHomePath Returns any manual project home path setting, or an empty string if not set.
projectStorage Returns pointer to project storage implementation that handles read/write of the project file.
read Reads given project file from the given file.
readBoolEntry
readDoubleEntry
readEntry
readLayer Reads the layer described in the associated DOM node.
readListEntry Key value accessors
readNumEntry
readPath Turn filename read from the project file to an absolute path
receivers
relationManager
reloadAllLayers Reload all registered layer’s provider data caches, synchronising the layer with any changes in the datasource.
removeAllMapLayers Removes all registered layers.
removeEntry Remove the given key
removeMapLayer Remove a layer from the registry by layer ID.
removeMapLayers Remove a set of layers from the registry by layer ID.
sender
senderSignalIndex
setAreaUnits Sets the default area measurement units for the project.
setAutoTransaction Transactional editing means that on supported datasources (postgres databases) the edit state of all tables that originate from the same database are synchronized and executed in a server side transaction.
setAvoidIntersectionsLayers A list of layers with which intersections should be avoided.
setBadLayerHandler Change handler for missing layers.
setCrs Sets the project’s native coordinate reference system.
setCustomVariables A map of custom project variables.
setDirty Flag the project as dirty (modified).
setDistanceUnits Sets the default distance measurement units for the project.
setEllipsoid Sets the project’s ellipsoid from a proj string representation, e.
setEvaluateDefaultValues Defines if default values should be evaluated on provider side when requested and not when committed.
setFileName Sets the file name associated with the project.
setLabelingEngineSettings Sets project’s global labeling engine settings
setMetadata Sets the project’s metadata store.
setNonIdentifiableLayers Set a list of layers which should not be taken into account on map identification
setPresetHomePath Sets the project’s home path.
setSnappingConfig The snapping configuration for this project.
setTitle Sets the project’s title.
setTopologicalEditing Convenience function to set topological editing
setTransformContext Sets the project’s coordinate transform context, which stores various information regarding which datum transforms should be used when transforming points from a source to destination coordinate reference system.
setTrustLayerMetadata Sets the trust option 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.
snappingConfig The snapping configuration for this project.
subkeyList Return keys with keys – do not return keys that contain only values
takeMapLayer Takes a layer from the registry.
timerEvent
title Returns the project’s title.
topologicalEditing Convenience function to query topological editing status
transformContext Returns a copy of the project’s coordinate transform context, which stores various information regarding which datum transforms should be used when transforming points from a source to destination coordinate reference system.
trustLayerMetadata Returns true if the trust option is activated, false otherwise.
write Writes the project to a file.
writeEntry Write an integer entry to the project file.
writeEntryBool Write a boolean entry to the project file.
writeEntryDouble Write a double entry to the project file.
writePath Prepare a filename to save it to the project file.

Signals

avoidIntersectionsLayersChanged Emitted whenever avoidIntersectionsLayers has changed.
crsChanged Emitted when the CRS of the project has changed.
customVariablesChanged Emitted whenever the expression variables stored in the project have been changed.
ellipsoidChanged Emitted when the project ellipsoid is changed.
fileNameChanged Emitted when the file name of the project changes [signal]
homePathChanged Emitted when the home path of the project changes.
isDirtyChanged Emitted when the project dirty status changes.
labelingEngineSettingsChanged Emitted when global configuration of the labeling engine changes.
layerLoaded Emitted when a layer from a projects was read.
layerRemoved Emitted after a layer was removed from the registry.
layerWasAdded Emitted when a layer was added to the registry.
layerWillBeRemoved Emitted when a layer is about to be removed from the registry.
layersAdded Emitted when one or more layers were added to the registry.
layersRemoved Emitted after one or more layers were removed from the registry.
layersWillBeRemoved Emitted when one or more layers are about to be removed from the registry.
legendLayersAdded Emitted, when a layer was added to the registry and the legend.
loadingLayer Emitted when a layer is loaded [signal]
loadingLayerMessageReceived Emitted when loading layers has produced some messages
mapThemeCollectionChanged Emitted when the map theme collection changes.
metadataChanged Emitted when the project’s metadata is changed.
missingDatumTransforms Emitted when datum transforms stored in the project are not available locally.
nonIdentifiableLayersChanged Emitted when the list of layer which are excluded from map identification changes [signal]
oldProjectVersionWarning emitted when an old project file is read.
projectSaved emitted when the project file has been written and closed [signal]
readMapLayer Emitted, after the basic initialization of a layer from the project file is done.
readProject emitted when project is being read [signal]
removeAll removeAll(self) [signal]
snappingConfigChanged emitted whenever the configuration for snapping has changed [signal]
topologicalEditingChanged Emitted when the topological editing flag has changed.
transactionGroupsChanged Emitted whenever a new transaction group has been created or a transaction group has been removed.
transformContextChanged Emitted when the project transformContext() is changed.
writeMapLayer Emitted, when a layer is being saved.
writeProject emitted when project is being written [signal]

Attributes

absoluteFilePath(self) → str

Returns full absolute path to the project file if the project is stored in a file system - derived from fileName(). Returns empty string when the project is stored in a project storage (there is no concept of paths for custom project storages).

New in version 3.2.

addMapLayer(self, mapLayer: QgsMapLayer, addToLegend: bool = True) → QgsMapLayer

Add a layer to the map of loaded layers.

The layersAdded() and layerWasAdded() signals will always be emitted. The legendLayersAdded() signal is emitted only if addToLegend is true. If you are adding multiple layers at once, you should use addMapLayers() instead.

Parameters:
  • mapLayer – A layer to add to the registry
  • addToLegend – If true (by default), the layer will be added to the

legend and to the main canvas. If you have a private layer you can set this parameter to false to hide it. :param takeOwnership: Ownership will be transferred to the layer registry. If you specify false here you have take care of deleting the layer yourself. Not available in Python.

Returns:None if unable to add layer, otherwise pointer to newly added layer

See also

addMapLayers()

Note

As a side-effect QgsProject is made dirty.

Note

Use addMapLayers if adding more than one layer at a time

Note

takeOwnership is not available in the Python bindings - the registry will always take ownership

See also

addMapLayers()

addMapLayers(self, mapLayers: Iterable[QgsMapLayer], addToLegend: bool = True) → List[QgsMapLayer]

Add a list of layers to the map of loaded layers.

The layersAdded() and layerWasAdded() signals will always be emitted. The legendLayersAdded() signal is emitted only if addToLegend is true.

Parameters:
  • mapLayers – A list of layer which should be added to the registry
  • addToLegend – If true (by default), the layers will be added to the

legend and to the main canvas. If you have a private layer you can set this parameter to false to hide it. :param takeOwnership: Ownership will be transferred to the layer registry. If you specify false here you have take care of deleting the layers yourself. Not available in Python.

Returns:a list of the map layers that were added

successfully. If a layer is invalid, or already exists in the registry, it will not be part of the returned QList.

Note

As a side-effect QgsProject is made dirty.

Note

takeOwnership is not available in the Python bindings - the registry will always take ownership

New in version 1.8.

See also

addMapLayer()

annotationManager(self) → QgsAnnotationManager

Returns pointer to the project’s annotation manager.

New in version 3.0.

areaUnits(self) → QgsUnitTypes.AreaUnit

Convenience function to query default area measurement units for project.

New in version 2.14.

See also

distanceUnits()

autoTransaction(self) → bool

Transactional editing means that on supported datasources (postgres databases) the edit state of all tables that originate from the same database are synchronized and executed in a server side transaction.

New in version 2.16.

auxiliaryStorage(self) → QgsAuxiliaryStorage

Returns the current auxiliary storage.

New in version 3.0.

avoidIntersectionsLayers(self) → List[QgsVectorLayer]

A list of layers with which intersections should be avoided.

New in version 3.0.

avoidIntersectionsLayersChanged

Emitted whenever avoidIntersectionsLayers has changed.

New in version 3.0: [signal]

baseName(self) → str

Returns the base name of the project file without the path and without extension - derived from fileName().

New in version 3.2.

blockDirtying

alias of qgis.core.ProjectDirtyBlocker

childEvent()
clear(self)

Clear the project - removes all settings and resets it back to an empty, default state.

New in version 2.4.

connectNotify()
count(self) → int

Returns the number of registered layers.

createEmbeddedGroup(self, groupName: str, projectFilePath: str, invisibleLayers: Iterable[str]) → QgsLayerTreeGroup

Create layer group instance defined in an arbitrary project file.

New in version 2.4.

createExpressionContext(self) → QgsExpressionContext
crs(self) → QgsCoordinateReferenceSystem

Returns the project’s native coordinate reference system.

New in version 3.0.

See also

setCrs()

See also

ellipsoid()

crsChanged

Emitted when the CRS of the project has changed.

New in version 3.0: [signal]

customEvent()
customVariables(self) → Dict[str, Any]

A map of custom project variables. To get all available variables including generated ones use QgsExpressionContextUtils.projectScope() instead.

customVariablesChanged

Emitted whenever the expression variables stored in the project have been changed.

New in version 3.0: [signal]

defaultCrsForNewLayers(self) → QgsCoordinateReferenceSystem

Returns the default CRS for new layers based on the settings and the current project CRS

disconnectNotify()
distanceUnits(self) → QgsUnitTypes.DistanceUnit

Convenience function to query default distance measurement units for project.

New in version 2.14.

See also

areaUnits()

dumpProperties(self)
ellipsoid(self) → str

Returns a proj string representing the project’s ellipsoid setting, e.g., “WGS84”.

See also

setEllipsoid()

See also

crs()

New in version 3.0.

ellipsoidChanged

Emitted when the project ellipsoid is changed.

New in version 3.0.

See also

setEllipsoid()

See also

ellipsoid() [signal]

entryList(self, scope: str, key: str) → List[str]

Return keys with values – do not return keys that contain other keys

Note

equivalent to QgsSettings entryList()

error(self) → str

Return error message from previous read/write

evaluateDefaultValues(self) → bool

Should default values be evaluated on provider side when requested and not when committed.

New in version 2.16.

fileInfo(self) → QFileInfo

Returns QFileInfo object for the project’s associated file.

Note

The use of this method is discouraged since QGIS 3.2 as it only works with project files stored in the file system. It is recommended to use absoluteFilePath(), baseName(), lastModifiedTime() as replacements that are aware of the fact that projects may be saved in other project storages.

See also

fileName()

New in version 2.9.

deprecated

fileName(self) → str

Returns the project’s file name. This is the file which contains the project’s XML representation.

See also

setFileName()

See also

fileInfo()

fileNameChanged

Emitted when the file name of the project changes [signal]

homePath(self) → str

Returns the project’s home path. This will either be a manually set home path (see presetHomePath()) or the path containing the project file itself.

This method always returns the absolute path to the project’s home. See presetHomePath() to retrieve any manual project home path override (e.g. relative home paths).

See also

presetHomePath()

homePathChanged

Emitted when the home path of the project changes.

See also

homePath()

See also

presetHomePath() [signal]

instance() → QgsProject

Returns the QgsProject singleton instance

isDirty(self) → bool

Returns true if the project has been modified since the last write()

isDirtyChanged

Emitted when the project dirty status changes.

Parameters:dirty – True if the project is in a dirty state and has pending unsaved changes.

New in version 3.2: [signal]

isSignalConnected()
isZipped(self) → bool

Returns true if the project comes from a zip archive, false otherwise.

labelingEngineSettings(self) → QgsLabelingEngineSettings

Returns project’s global labeling engine settings

New in version 3.0.

labelingEngineSettingsChanged

Emitted when global configuration of the labeling engine changes.

New in version 3.0: [signal]

lastModified(self) → QDateTime

Returns last modified time of the project file as returned by the file system (or other project storage).

New in version 3.2.

layerIsEmbedded(self, id: str) → str

Returns project file path if layer is embedded from other project file. Returns empty string if layer is not embedded

layerLoaded

Emitted when a layer from a projects was read.

Parameters:
  • i – current layer
  • n – number of layers [signal]
layerRemoved

Emitted after a layer was removed from the registry.

Parameters:layerId – The ID of the layer removed.

Note

Consider using layersRemoved() instead

See also

layerWillBeRemoved() [signal]

layerStore(self) → QgsMapLayerStore

Returns a pointer to the project’s internal layer store. /since QGIS 3.0

layerTreeRegistryBridge(self) → QgsLayerTreeRegistryBridge

Return pointer to the helper class that synchronizes map layer registry with layer tree

New in version 2.4.

layerTreeRoot(self) → QgsLayerTree

Return pointer to the root (invisible) node of the project’s layer tree

New in version 2.4.

layerWasAdded

Emitted when a layer was added to the registry.

Note

Consider using layersAdded() instead

See also

layersAdded() [signal]

layerWillBeRemoved

Emitted when a layer is about to be removed from the registry.

Parameters:layerId – The ID of the layer to be removed.

Note

Consider using layersWillBeRemoved() instead

See also

layerRemoved() [signal]

layerWillBeRemoved(self, QgsMapLayer) Emitted when a layer is about to be removed from the registry.

Parameters:layer – The layer to be removed.

Note

Consider using layersWillBeRemoved() instead

See also

layerRemoved() [signal]

layersAdded

Emitted when one or more layers were added to the registry. This signal is also emitted for layers added to the registry, but not to the legend.

Parameters:layers – List of layers which have been added.

See also

layerWasAdded() [signal]

layersRemoved

Emitted after one or more layers were removed from the registry.

Parameters:layerIds – A list of IDs of the layers which were removed.

See also

layersWillBeRemoved() [signal]

layersWillBeRemoved

Emitted when one or more layers are about to be removed from the registry.

Parameters:layerIds – A list of IDs for the layers which are to be removed.

See also

layersRemoved() [signal]

layersWillBeRemoved(self, Iterable[QgsMapLayer]) Emitted when one or more layers are about to be removed from the registry.

Parameters:layers – A list of layers which are to be removed.

See also

layersRemoved() [signal]

layoutManager(self) → QgsLayoutManager

Returns the project’s layout manager, which manages compositions within the project.

New in version 3.0.

legendLayersAdded

Emitted, when a layer was added to the registry and the legend. Layers can also be private layers, which are signalled by layersAdded() and layerWasAdded() but will not be advertised by this signal.

Parameters:layers – List of QgsMapLayer which were added to the legend. [signal]
loadingLayer

Emitted when a layer is loaded [signal]

loadingLayerMessageReceived

Emitted when loading layers has produced some messages

Parameters:
  • layerName – the layer name
  • messages – a list of pairs of Qgis.MessageLevel and messages

New in version 3.2: [signal]

mapLayer(self, layerId: str) → QgsMapLayer

Retrieve a pointer to a registered layer by layer ID.

Parameters:layerId – ID of layer to retrieve
Returns:matching layer, or None if no matching layer found

See also

mapLayers()

mapLayers(self) → object

Returns a map of all registered layers by layer ID.

See also

mapLayer()

See also

layers()

mapLayersByName(self, layerName: str) → List[QgsMapLayer]

Retrieve a list of matching registered layers by layer name.

Parameters:layerName – name of layers to match
Returns:list of matching layers

See also

mapLayer()

See also

mapLayers()

mapThemeCollection(self) → QgsMapThemeCollection

Returns pointer to the project’s map theme collection.

New in version 2.12.

Note

renamed in QGIS 3.0, formerly QgsVisibilityPresetCollection

mapThemeCollectionChanged

Emitted when the map theme collection changes. This only happens when the map theme collection is reset. Any pointer previously received from mapThemeCollection() must no longer be used after this signal is emitted. You must still connect to signals from the map theme collection if you want to be notified about new map themes being added and map themes being removed.

New in version 3.0: [signal]

metadata(self) → QgsProjectMetadata

Returns a reference to the project’s metadata store.

New in version 3.2.

See also

setMetadata()

metadataChanged

Emitted when the project’s metadata is changed.

See also

setMetadata()

See also

metadata()

New in version 3.2: [signal]

missingDatumTransforms

Emitted when datum transforms stored in the project are not available locally.

New in version 3.0: [signal]

nonIdentifiableLayers(self) → List[str]

Get the list of layers which currently should not be taken into account on map identification

nonIdentifiableLayersChanged

Emitted when the list of layer which are excluded from map identification changes [signal]

oldProjectVersionWarning

emitted when an old project file is read. [signal]

pathResolver(self) → QgsPathResolver

Return path resolver object with considering whether the project uses absolute or relative paths and using current project’s path.

New in version 3.0.

presetHomePath(self) → str

Returns any manual project home path setting, or an empty string if not set.

This path may be a relative path. See homePath() to retrieve a path which is always an absolute path.

See also

homePath()

New in version 3.2.

projectSaved

emitted when the project file has been written and closed [signal]

projectStorage(self) → QgsProjectStorage

Returns pointer to project storage implementation that handles read/write of the project file. If the project file is stored in the local file system, returns null pointer. The project storage object is inferred from fileName() of the project.

New in version 3.2.

read(self, filename: str) → bool

Reads given project file from the given file.

Parameters:filename – name of project file to read
Returns:true if project file has been read successfully

read(self) -> bool Reads the project from its currently associated file (see fileName() ).

Returns:true if project file has been read successfully
readBoolEntry(self, scope: str, key: str, def_: bool = False) → Tuple[bool, bool]
readDoubleEntry(self, scope: str, key: str, def_: float = 0) → Tuple[float, bool]
readEntry(self, scope: str, key: str, def_: str = '') → Tuple[str, bool]
readLayer(self, layerNode: QDomNode) → bool

Reads the layer described in the associated DOM node.

Note

This method is mainly for use by QgsProjectBadLayerHandler subclasses that may fix definition of bad layers with the user’s help in GUI. Calling this method with corrected DOM node adds the layer back to the project.

Parameters:layerNode – represents a QgsProject DOM node that encodes a specific layer.
readListEntry(self, scope: str, key: str, def_: Iterable[str] = []) → Tuple[List[str], bool]

Key value accessors

keys would be the familiar QgsSettings-like ‘/’ delimited entries, implying a hierarchy of keys and corresponding values

readMapLayer

Emitted, after the basic initialization of a layer from the project file is done. You can use this signal to read additional information from the project file.

Parameters:
  • mapLayer – The map layer which is being initialized
  • layerNode – The layer node from the project file [signal]
readNumEntry(self, scope: str, key: str, def_: int = 0) → Tuple[int, bool]
readPath(self, filename: str) → str

Turn filename read from the project file to an absolute path

readProject

emitted when project is being read [signal]

receivers()
relationManager(self) → QgsRelationManager
reloadAllLayers(self)

Reload all registered layer’s provider data caches, synchronising the layer with any changes in the datasource.

removeAll

removeAll(self) [signal]

removeAllMapLayers(self)

Removes all registered layers. If the registry has ownership of any layers these layers will also be deleted.

Note

As a side-effect the QgsProject instance is marked dirty.

Note

Calling this method will cause the removeAll() signal to be emitted.

See also

removeMapLayer()

removeEntry(self, scope: str, key: str) → bool

Remove the given key

removeMapLayer(self, layerId: str)

Remove a layer from the registry by layer ID.

The specified layer will be removed from the registry. If the registry has ownership of the layer then it will also be deleted.

Parameters:layerId – ID of the layer to remove

Note

As a side-effect the QgsProject instance is marked dirty.

removeMapLayer(self, layer: QgsMapLayer) Remove a layer from the registry.

The specified layer will be removed from the registry. If the registry has ownership of the layer then it will also be deleted.

Parameters:layer – The layer to remove. Null pointers are ignored.

Note

As a side-effect the QgsProject instance is marked dirty.

removeMapLayers(self, layerIds: Iterable[str])

Remove a set of layers from the registry by layer ID.

The specified layers will be removed from the registry. If the registry has ownership of any layers these layers will also be deleted.

Parameters:layerIds – list of IDs of the layers to remove

Note

As a side-effect the QgsProject instance is marked dirty.

New in version 1.8.

See also

removeMapLayer()

removeMapLayers(self, layers: Iterable[QgsMapLayer])

sender()
senderSignalIndex()
setAreaUnits(self, unit: QgsUnitTypes.AreaUnit)

Sets the default area measurement units for the project.

New in version 3.0.

See also

areaUnits()

setAutoTransaction(self, autoTransaction: bool)

Transactional editing means that on supported datasources (postgres databases) the edit state of all tables that originate from the same database are synchronized and executed in a server side transaction.

Make sure that this is only called when all layers are not in edit mode.

New in version 2.16.

setAvoidIntersectionsLayers(self, layers: Iterable[QgsVectorLayer])

A list of layers with which intersections should be avoided.

New in version 3.0.

setBadLayerHandler(self, handler: QgsProjectBadLayerHandler)

Change handler for missing layers. Deletes old handler and takes ownership of the new one.

setCrs(self, crs: QgsCoordinateReferenceSystem)

Sets the project’s native coordinate reference system.

New in version 3.0.

See also

crs()

See also

setEllipsoid()

setCustomVariables(self, customVariables: Dict[str, Any])

A map of custom project variables. Be careful not to set generated variables.

setDirty(self, b: bool = True)

Flag the project as dirty (modified). If this flag is set, the user will be asked to save changes to the project before closing the current project.

New in version 2.4.

Note

promoted to public slot in 2.16

setDistanceUnits(self, unit: QgsUnitTypes.DistanceUnit)

Sets the default distance measurement units for the project.

New in version 3.0.

See also

distanceUnits()

See also

setAreaUnits()

setEllipsoid(self, ellipsoid: str)

Sets the project’s ellipsoid from a proj string representation, e.g., “WGS84”.

See also

ellipsoid()

See also

setCrs()

New in version 3.0.

setEvaluateDefaultValues(self, evaluateDefaultValues: bool)

Defines if default values should be evaluated on provider side when requested and not when committed.

New in version 2.16.

setFileName(self, name: str)

Sets the file name associated with the project. This is the file which contains the project’s XML representation.

Parameters:name – project file name

See also

fileName()

setLabelingEngineSettings(self, settings: QgsLabelingEngineSettings)

Sets project’s global labeling engine settings

New in version 3.0.

setMetadata(self, metadata: QgsProjectMetadata)

Sets the project’s metadata store.

New in version 3.2.

See also

metadata()

setNonIdentifiableLayers(self, layers: Iterable[QgsMapLayer])

Set a list of layers which should not be taken into account on map identification

setNonIdentifiableLayers(self, layerIds: Iterable[str]) Set a list of layers which should not be taken into account on map identification

setPresetHomePath(self, path: str)

Sets the project’s home path. If an empty path is specified than the home path will be automatically determined from the project’s file path.

New in version 3.2.

See also

presetHomePath()

See also

homePath()

setSnappingConfig(self, snappingConfig: QgsSnappingConfig)

The snapping configuration for this project.

New in version 3.0.

setTitle(self, title: str)

Sets the project’s title.

Parameters:title – new title

New in version 2.4.

Note

Since QGIS 3.2 this is just a shortcut to setting the title in the project’s metadata().

See also

title()

setTopologicalEditing(self, enabled: bool)

Convenience function to set topological editing

setTransformContext(self, context: QgsCoordinateTransformContext)

Sets the project’s coordinate transform context, which stores various information regarding which datum transforms should be used when transforming points from a source to destination coordinate reference system.

New in version 3.0.

setTrustLayerMetadata(self, trust: bool)

Sets the trust option 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. Moreover, when this option is activated, primary key unicity is not checked for views and materialized views with Postgres provider.

Parameters:trust – True to trust the project, false otherwise

New in version 3.0.

snappingConfig(self) → QgsSnappingConfig

The snapping configuration for this project.

New in version 3.0.

snappingConfigChanged

emitted whenever the configuration for snapping has changed [signal]

subkeyList(self, scope: str, key: str) → List[str]

Return keys with keys – do not return keys that contain only values

Note

equivalent to QgsSettings subkeyList()

takeMapLayer(self, layer: QgsMapLayer) → QgsMapLayer

Takes a layer from the registry. If the layer was owned by the project, the layer will be returned without deleting it. The caller takes ownership of the layer and is responsible for deleting it.

See also

removeMapLayer()

New in version 3.0.

timerEvent()
title(self) → str

Returns the project’s title.

See also

setTitle()

Note

Since QGIS 3.2 this is just a shortcut to retrieving the title from the project’s metadata().

topologicalEditing(self) → bool

Convenience function to query topological editing status

topologicalEditingChanged

Emitted when the topological editing flag has changed.

New in version 3.0: [signal]

transactionGroupsChanged

Emitted whenever a new transaction group has been created or a transaction group has been removed.

New in version 3.0: [signal]

transformContext(self) → QgsCoordinateTransformContext

Returns a copy of the project’s coordinate transform context, which stores various information regarding which datum transforms should be used when transforming points from a source to destination coordinate reference system.

New in version 3.0.

transformContextChanged

Emitted when the project transformContext() is changed.

New in version 3.0.

See also

transformContext() [signal]

trustLayerMetadata(self) → bool

Returns true if the trust option is activated, false otherwise. This option allows indicateing 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. Moreover, when this option is activated, primary key unicity is not checked for views and materialized views with Postgres provider.

New in version 3.0.

write(self, filename: str) → bool

Writes the project to a file.

Parameters:filename – destination file
Returns:true if project was written successfully

Note

calling this implicitly sets the project’s filename (see setFileName() )

Note

isDirty() will be set to false if project is successfully written

New in version 3.0.

write(self) -> bool Writes the project to its current associated file (see fileName() ).

Returns:true if project was written successfully

Note

isDirty() will be set to false if project is successfully written

writeEntry(self, scope: str, key: str, value: int) → bool

Write an integer entry to the project file.

Keys are ‘/’-delimited entries, implying a hierarchy of keys and corresponding values

Note

The key string must be valid xml tag names in order to be saved to the file.

writeEntry(self, scope: str, key: str, value: str) -> bool Write a string entry to the project file.

Keys are ‘/’-delimited entries, implying a hierarchy of keys and corresponding values

Note

The key string must be valid xml tag names in order to be saved to the file.

writeEntry(self, scope: str, key: str, value: Iterable[str]) -> bool Write a string list entry to the project file.

Keys are ‘/’-delimited entries, implying a hierarchy of keys and corresponding values

Note

The key string must be valid xml tag names in order to be saved to the file.

writeEntryBool(self, scope: str, key: str, value: bool) → bool

Write a boolean entry to the project file.

Keys are ‘/’-delimited entries, implying a hierarchy of keys and corresponding values

Note

The key string must be valid xml tag names in order to be saved to the file.

Note

available in Python bindings as writeEntryBool

writeEntryDouble(self, scope: str, key: str, value: float) → bool

Write a double entry to the project file.

Keys are ‘/’-delimited entries, implying a hierarchy of keys and corresponding values

Note

The key string must be valid xml tag names in order to be saved to the file.

Note

available in Python bindings as writeEntryDouble

writeMapLayer

Emitted, when a layer is being saved. You can use this method to save additional information to the layer.

Parameters:
  • mapLayer – The map layer which is being initialized
  • layerElem – The layer element from the project file
  • doc – The document [signal]
writePath(self, filename: str) → str

Prepare a filename to save it to the project file. Creates an absolute or relative path according to the project settings. Paths written to the project file should be prepared with this method.

writeProject

emitted when project is being written [signal]