Class LayerUtils

ClassList > LayerUtils

Inherits the following classes: QObject

Public Functions

Type	Name
	LayerUtils (QObject * parent=nullptr)
Q_INVOKABLE QSet< QVariant >	uniqueValuesForVectorLayerFieldIndex (QgsVectorLayer * layer, int fieldIndex)

Public Static Functions

Type	Name
Q_INVOKABLE bool	addFeature (QgsVectorLayer * layer, QgsFeature feature)
QgsMapLayer *	createBasemap (const QString & style=QString())
Q_INVOKABLE FeatureIterator	createFeatureIterator (QgsVectorLayer * layer)
Q_INVOKABLE FeatureIterator	createFeatureIteratorFromExpression (QgsVectorLayer * layer, const QString & expression)
Q_INVOKABLE FeatureIterator	createFeatureIteratorFromRectangle (QgsVectorLayer * layer, const QgsRectangle & rectangle)
Q_INVOKABLE QgsVectorLayer *	createMemoryLayer (const QString & name, const QgsFields & fields=QgsFields(), Qgis::WkbType geometryType=Qgis::WkbType::NoGeometry, const QgsCoordinateReferenceSystem & crs=QgsCoordinateReferenceSystem())
QgsRasterLayer *	createOnlineElevationLayer ()
QgsAbstractVectorLayerLabeling *	defaultLabeling (QgsVectorLayer * layer, QgsTextFormat textFormat=QgsTextFormat())
QgsSymbol *	defaultSymbol (QgsVectorLayer * layer, const QString & attachmentField=QString(), const QString & colorField=QString())
Q_INVOKABLE bool	deleteFeature (QgsProject * project, QgsVectorLayer * layer, const QgsFeatureId fid, bool flushBuffer=true)
Q_INVOKABLE QgsFeature	duplicateFeature (QgsVectorLayer * layer, QgsFeature feature)
Q_INVOKABLE QString	fieldType (const QgsField & field)
Q_INVOKABLE bool	hasMValue (QgsVectorLayer * layer)
Q_INVOKABLE bool	isAtlasCoverageLayer (QgsVectorLayer * layer)
Q_INVOKABLE bool	isFeatureAdditionLocked (QgsMapLayer * layer)
Q_INVOKABLE QgsRasterLayer *	loadRasterLayer (const QString & uri, const QString & name=QString(), const QString & provider=QStringLiteral("gdal"))
Q_INVOKABLE QgsVectorLayer *	loadVectorLayer (const QString & uri, const QString & name=QString(), const QString & provider=QStringLiteral("ogr"))
Q_INVOKABLE QgsVectorLayer *	memoryLayerFromJsonString (const QString & name, const QString & string, const QgsCoordinateReferenceSystem & crs=QgsCoordinateReferenceSystem())
Q_INVOKABLE QString	saveVectorLayerAs (QgsVectorLayer * layer, const QString & filePath, const QString & driverName=QString(), const QString & filterExpression=QString())
Q_INVOKABLE void	selectFeaturesInLayer (QgsVectorLayer * layer, const QList< int > & fids, Qgis::SelectBehavior behavior=Qgis::SelectBehavior::SetSelection)
void	setDefaultLabeling (QgsVectorLayer * layer, QgsProject * project=nullptr)
void	setDefaultRenderer (QgsVectorLayer * layer, QgsProject * project=nullptr, const QString & attachmentField=QString(), const QString & colorField=QString())

Public Functions Documentation

function LayerUtils

explicit LayerUtils::LayerUtils (
    QObject * parent=nullptr
) 

---

function uniqueValuesForVectorLayerFieldIndex

Q_INVOKABLE QSet< QVariant > LayerUtils::uniqueValuesForVectorLayerFieldIndex (
    QgsVectorLayer * layer,
    int fieldIndex
) 

Returns a list of unique values for a given fieldIndex from the layer.

---

Public Static Functions Documentation

function addFeature

static Q_INVOKABLE bool LayerUtils::addFeature (
    QgsVectorLayer * layer,
    QgsFeature feature
) 

Adds a feature into the layer.

Note:

The function will not call startEditing() and commitChanges()

---

function createBasemap

static QgsMapLayer * LayerUtils::createBasemap (
    const QString & style=QString()
) 

Creates an online basemap layer.

---

function createFeatureIterator

static Q_INVOKABLE FeatureIterator LayerUtils::createFeatureIterator (
    QgsVectorLayer * layer
) 

Returns a feature iterator to get all features within the provided layer.

---

function createFeatureIteratorFromExpression

static Q_INVOKABLE FeatureIterator LayerUtils::createFeatureIteratorFromExpression (
    QgsVectorLayer * layer,
    const QString & expression
) 

Returns a feature iterator to get features matching a given expression within the provided layer.

---

function createFeatureIteratorFromRectangle

static Q_INVOKABLE FeatureIterator LayerUtils::createFeatureIteratorFromRectangle (
    QgsVectorLayer * layer,
    const QgsRectangle & rectangle
) 

Returns a feature iterator to get features overlapping a given rectangle within the provided layer.

---

function createMemoryLayer

static Q_INVOKABLE QgsVectorLayer * LayerUtils::createMemoryLayer (
    const QString & name,
    const QgsFields & fields=QgsFields(),
    Qgis::WkbType geometryType=Qgis::WkbType::NoGeometry,
    const QgsCoordinateReferenceSystem & crs=QgsCoordinateReferenceSystem()
) 

Creates a new memory layer using the specified parameters.

Parameters:

• name layer name
• fields fields for layer
• geometryType optional layer geometry type
• crs optional layer CRS for layers with geometry

---

function createOnlineElevationLayer

static QgsRasterLayer * LayerUtils::createOnlineElevationLayer () 

Creats an online raster elevation layer.

---

function defaultLabeling

static QgsAbstractVectorLayerLabeling * LayerUtils::defaultLabeling (
    QgsVectorLayer * layer,
    QgsTextFormat textFormat=QgsTextFormat()
) 

Returns the default vector layer labeling for a given layer and textFormat.

---

function defaultSymbol

static QgsSymbol * LayerUtils::defaultSymbol (
    QgsVectorLayer * layer,
    const QString & attachmentField=QString(),
    const QString & colorField=QString()
) 

Returns the default symbol for a given layer.

Parameters:

• layer the vector layer used to create the default symbol

---

function deleteFeature

static Q_INVOKABLE bool LayerUtils::deleteFeature (
    QgsProject * project,
    QgsVectorLayer * layer,
    const QgsFeatureId fid,
    bool flushBuffer=true
) 

Deletes a vector layer feature, including related features tied to relationships.

Parameters:

• project the project holding information on relationships
• layer the layer from which the feature will be deleted
• fid the feature ID to be deleted
• flushBuffer set to TRUE to immediately save the edit buffer

---

function duplicateFeature

static Q_INVOKABLE QgsFeature LayerUtils::duplicateFeature (
    QgsVectorLayer * layer,
    QgsFeature feature
) 

Duplicates a given feature within the provided vector layer. If successful, the function will return the duplicated feature with attribute values saved updated to match what was saved into the layer dataset.

---

function fieldType

static Q_INVOKABLE QString LayerUtils::fieldType (
    const QgsField & field
) 

Returns the QVariant typeName of a field. This is a stable identifier (compared to the provider field name).

---

function hasMValue

static Q_INVOKABLE bool LayerUtils::hasMValue (
    QgsVectorLayer * layer
) 

Returns TRUE if the vector layer geometry has an M value.

---

function isAtlasCoverageLayer

static Q_INVOKABLE bool LayerUtils::isAtlasCoverageLayer (
    QgsVectorLayer * layer
) 

Returns TRUE if the vector layer is used as an atlas coverage layer in any of the print layouts of the currently opened project.

Parameters:

• layer the vector layer to check against print layouts

---

function isFeatureAdditionLocked

static Q_INVOKABLE bool LayerUtils::isFeatureAdditionLocked (
    QgsMapLayer * layer
) 

Returns TRUE if the layer permission state prevents feature addition.

---

function loadRasterLayer

static Q_INVOKABLE QgsRasterLayer * LayerUtils::loadRasterLayer (
    const QString & uri,
    const QString & name=QString(),
    const QString & provider=QStringLiteral("gdal")
) 

Loads a raster layer.

Parameters:

• uri the data source uri
• name the layer name
• provider the data provider name

---

function loadVectorLayer

static Q_INVOKABLE QgsVectorLayer * LayerUtils::loadVectorLayer (
    const QString & uri,
    const QString & name=QString(),
    const QString & provider=QStringLiteral("ogr")
) 

Loads a vector layer.

Parameters:

• uri the data source uri
• name the layer name
• provider the data provider name

---

function memoryLayerFromJsonString

static Q_INVOKABLE QgsVectorLayer * LayerUtils::memoryLayerFromJsonString (
    const QString & name,
    const QString & string,
    const QgsCoordinateReferenceSystem & crs=QgsCoordinateReferenceSystem()
) 

Attempts to parse a GeoJSON string to a memory vector layer containing the collection of features. The geometry type will be taken from the first parsed feature.

Parameters:

• name layer name
• string the GeoJSON string
• crs optional layer CRS for layers with geometry

---

function saveVectorLayerAs

static Q_INVOKABLE QString LayerUtils::saveVectorLayerAs (
    QgsVectorLayer * layer,
    const QString & filePath,
    const QString & driverName=QString(),
    const QString & filterExpression=QString()
) 

Saves a vector layer into an on-disk dataset a given path using the OGR provider.

Parameters:

• layer the vector layer to save features from
• filePath the file path where the dataset will be writen
• driverName an optional OGR driver name (if left empty, the file path extension will drive the OGR driver)
• filterExpression an optional filter expression used to save a subset of features from the layer (note that only the global, project, and layer expression context scopes are used)

Returns:

If successful, finalized file path will be returned, otherwise an empty string will be returned

---

function selectFeaturesInLayer

static Q_INVOKABLE void LayerUtils::selectFeaturesInLayer (
    QgsVectorLayer * layer,
    const QList< int > & fids,
    Qgis::SelectBehavior behavior=Qgis::SelectBehavior::SetSelection
) 

Selects features in a layer This method is required since QML cannot perform the conversion of a feature ID to a QgsFeatureId

Parameters:

• layer the vector layer
• fids the list of feature IDs
• behavior the selection behavior

---

function setDefaultLabeling

static void LayerUtils::setDefaultLabeling (
    QgsVectorLayer * layer,
    QgsProject * project=nullptr
) 

Sets the default labeling for a given layer.

---

function setDefaultRenderer

static void LayerUtils::setDefaultRenderer (
    QgsVectorLayer * layer,
    QgsProject * project=nullptr,
    const QString & attachmentField=QString(),
    const QString & colorField=QString()
) 

Sets the default symbology render for a given layer.

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The documentation for this class was generated from the following file src/core/utils/layerutils.h