QgsVectorFileWriter class

Base classes

class QgsFeatureSink

An interface for objects which accept features via addFeature(s) methods.

Public types

struct DriverDetails

Details of available driver formats.

class FieldValueConverter

Interface to convert raw field values to their user-friendly value.

struct FilterFormatDetails

Details of available filters and formats.

class SaveVectorOptions

Options to pass to writeAsVectorFormat()

enum ActionOnExistingFile { CreateOrOverwriteFile, CreateOrOverwriteLayer, AppendToLayerNoNewFields, AppendToLayerAddFields }

Combination of CanAddNewLayer, CanAppendToExistingLayer, CanAddNewFieldsToExistingLayer or CanDeleteLayer.

enum EditionCapability { CanAddNewLayer = 1 << 0, CanAppendToExistingLayer = 1 << 1, CanAddNewFieldsToExistingLayer = 1 << 2, CanDeleteLayer = 1 << 3 }

Edition capability flags.

enum VectorFormatOption { SortRecommended = 1 << 1, SkipNonSpatialFormats = 1 << 2 }

Options for sorting and filtering vector formats.

enum WriterError { NoError = 0, ErrDriverNotFound, ErrCreateDataSource, ErrCreateLayer, ErrAttributeTypeUnsupported, ErrAttributeCreationFailed, ErrProjection, ErrFeatureWriteFailed, ErrInvalidLayer, Canceled }

Public static functions

static auto areThereNewFieldsToCreate(const QString& datasetName, const QString& layerName, QgsVectorLayer* layer, const QgsAttributeList& attributes) -> bool

Returns whether there are among the attributes specified some that do not exist yet in the layer.

static auto convertCodecNameForEncodingOption(const QString& codecName) -> QString

Converts codec name to string passed to ENCODING layer creation option of OGR Shapefile.

static auto defaultDatasetOptions(const QString& driverName) -> QStringList

Returns a list of the default dataset options for a specified driver.

static auto defaultLayerOptions(const QString& driverName) -> QStringList

Returns a list of the default layer options for a specified driver.

static auto deleteShapeFile(const QString& fileName) -> bool

Delete a shapefile (and its accompanying shx / dbf / prf)

static auto driverForExtension(const QString& extension) -> QString

Returns the OGR driver name for a specified file extension.

static auto editionCapabilities(const QString& datasetName) -> QgsVectorFileWriter::EditionCapabilities

Returns edition capabilities for an existing dataset name.

static auto fileFilterString(VectorFormatOptions options = SortRecommended) -> QString

Returns filter string that can be used for dialogs.

static auto filterForDriver(const QString& driverName) -> QString

Creates a filter for an OGR driver key.

static auto ogrDriverList(VectorFormatOptions options = SortRecommended) -> QList<QgsVectorFileWriter::DriverDetails>

Returns the driver list that can be used for dialogs.

static auto ogrTypeFromWkbType(QgsWkbTypes::Type type) -> OGRwkbGeometryType

Gets the ogr geometry type from an internal QGIS wkb type enum.

static auto supportedFiltersAndFormats(VectorFormatOptions options = SortRecommended) -> QList<QgsVectorFileWriter::FilterFormatDetails>

Returns a list or pairs, with format filter string as first element and OGR format key as second element.

static auto supportedFormatExtensions(VectorFormatOptions options = SortRecommended) -> QStringList

Returns a list of file extensions for supported formats, e.g "shp", "gpkg".

static auto supportsFeatureStyles(const QString& driverName) -> bool

Returns true if the specified driverName supports feature styles.

static auto targetLayerExists(const QString& datasetName, const QString& layerName) -> bool

Returns whether the target layer already exists.

static auto writeAsVectorFormat(QgsVectorLayer* layer, const QString& fileName, const QString& fileEncoding, const QgsCoordinateReferenceSystem& destCRS = QgsCoordinateReferenceSystem(), const QString& driverName = "GPKG", bool onlySelected = false, QString* errorMessage = nullptr, const QStringList& datasourceOptions = QStringList(), const QStringList& layerOptions = QStringList(), bool skipAttributeCreation = false, QString* newFilename = nullptr, QgsVectorFileWriter::SymbologyExport symbologyExport = QgsVectorFileWriter::NoSymbology, double symbologyScale = 1.0, const QgsRectangle* filterExtent = nullptr, QgsWkbTypes::Type overrideGeometryType = QgsWkbTypes::Unknown, bool forceMulti = false, bool includeZ = false, const QgsAttributeList& attributes = QgsAttributeList(), QgsVectorFileWriter::FieldValueConverter* fieldValueConverter = nullptr, QString* newLayer = nullptr) -> QgsVectorFileWriter::WriterError

Write contents of vector layer to an (OGR supported) vector format.

static auto writeAsVectorFormat(QgsVectorLayer* layer, const QString& fileName, const QString& fileEncoding, const QgsCoordinateTransform& ct, const QString& driverName = "GPKG", bool onlySelected = false, QString* errorMessage = nullptr, const QStringList& datasourceOptions = QStringList(), const QStringList& layerOptions = QStringList(), bool skipAttributeCreation = false, QString* newFilename = nullptr, QgsVectorFileWriter::SymbologyExport symbologyExport = QgsVectorFileWriter::NoSymbology, double symbologyScale = 1.0, const QgsRectangle* filterExtent = nullptr, QgsWkbTypes::Type overrideGeometryType = QgsWkbTypes::Unknown, bool forceMulti = false, bool includeZ = false, const QgsAttributeList& attributes = QgsAttributeList(), QgsVectorFileWriter::FieldValueConverter* fieldValueConverter = nullptr, QString* newLayer = nullptr) -> QgsVectorFileWriter::WriterError

Writes a layer out to a vector file.

static auto writeAsVectorFormat(QgsVectorLayer* layer, const QString& fileName, const QgsVectorFileWriter::SaveVectorOptions& options, QString* newFilename = nullptr, QString* errorMessage = nullptr, QString* newLayer = nullptr) -> QgsVectorFileWriter::WriterError

Writes a layer out to a vector file.

Constructors, destructors, conversion operators

QgsVectorFileWriter(const QString& vectorFileName, const QString& fileEncoding, const QgsFields& fields, QgsWkbTypes::Type geometryType, const QgsCoordinateReferenceSystem& srs = QgsCoordinateReferenceSystem(), const QString& driverName = "GPKG", const QStringList& datasourceOptions = QStringList(), const QStringList& layerOptions = QStringList(), QString* newFilename = nullptr, QgsVectorFileWriter::SymbologyExport symbologyExport = QgsVectorFileWriter::NoSymbology, QgsFeatureSink::SinkFlags sinkFlags = nullptr, QString* newLayer = nullptr)

Create a new vector file writer.

QgsVectorFileWriter(const QString& vectorFileName, const QString& fileEncoding, const QgsFields& fields, QgsWkbTypes::Type geometryType, const QgsCoordinateReferenceSystem& srs, const QString& driverName, const QStringList& datasourceOptions, const QStringList& layerOptions, QString* newFilename, QgsVectorFileWriter::SymbologyExport symbologyExport, QgsVectorFileWriter::FieldValueConverter* fieldValueConverter, const QString& layerName, QgsVectorFileWriter::ActionOnExistingFile action, QString* newLayer = nullptr)

Create a new vector file writer.

QgsVectorFileWriter(const QgsVectorFileWriter& rh) deleted

QgsVectorFileWriter cannot be copied.

~QgsVectorFileWriter() override

Close opened shapefile for writing.

Public functions

auto addFeature(QgsFeature& feature, QgsFeatureSink::Flags flags = nullptr) -> bool override

Adds a single feature to the sink.

auto addFeatures(QgsFeatureList& features, QgsFeatureSink::Flags flags = nullptr) -> bool override

Adds a list of features to the sink.

auto addFeatureWithStyle(QgsFeature& feature, QgsFeatureRenderer* renderer, QgsUnitTypes::DistanceUnit outputUnit = QgsUnitTypes::DistanceMeters) -> bool

Adds a feature to the currently opened data source, using the style from a specified renderer.

auto attrIdxToOgrIdx() -> QMap<int, int>

auto errorMessage() -> QString

Retrieves error message.

auto hasError() -> QgsVectorFileWriter::WriterError

Checks whether there were any errors in constructor.

auto operator=(const QgsVectorFileWriter& rh) -> QgsVectorFileWriter& deleted

QgsVectorFileWriter cannot be copied.

void setSymbologyScale(double scale)

Set reference scale for output.

auto symbologyScale() const -> double

Returns the reference scale for output.

Protected functions

auto createEmptyGeometry(QgsWkbTypes::Type wkbType) -> OGRGeometryH

Protected variables

QMap<int, int> mAttrIdxToOgrIdx

Map attribute indizes to OGR field indexes.

WriterError mError

Contains error value if construction was not successful.

FieldValueConverter* mFieldValueConverter

Field value converter.

double mSymbologyScale

Scale for symbology export (e.g. for symbols units in map units)

QgsWkbTypes::Type mWkbType

Geometry type which is being used.

Enum documentation

Function documentation