QgsVectorFileWriter Class Reference

A convenience class for writing vector files to disk. More...

#include <qgsvectorfilewriter.h>

Inheritance diagram for QgsVectorFileWriter:

Classes
class	BoolOption
struct	DriverDetails
	Details of available driver formats. More...
class	FieldValueConverter
	Interface to convert raw field values to their user-friendly value. More...
struct	FilterFormatDetails
	Details of available filters and formats. More...
class	HiddenOption
class	IntOption
struct	MetaData
class	Option
class	SaveVectorOptions
	Options to pass to writeAsVectorFormat() More...
class	SetOption
class	StringOption

Public Types
enum	ActionOnExistingFile { CreateOrOverwriteFile, CreateOrOverwriteLayer, AppendToLayerNoNewFields, AppendToLayerAddFields }
	Combination of CanAddNewLayer, CanAppendToExistingLayer, CanAddNewFieldsToExistingLayer or CanDeleteLayer. More...
enum	EditionCapability { CanAddNewLayer = 1 << 0, CanAppendToExistingLayer = 1 << 1, CanAddNewFieldsToExistingLayer = 1 << 2, CanDeleteLayer = 1 << 3 }
	Edition capability flags. More...
enum	OptionType { Set, String, Int, Hidden }
enum	SymbologyExport { NoSymbology = 0, FeatureSymbology, SymbolLayerSymbology }
enum	VectorFormatOption { SortRecommended = 1 << 1, SkipNonSpatialFormats = 1 << 2 }
	Options for sorting and filtering vector formats. More...
enum	WriterError {   NoError = 0, ErrDriverNotFound, ErrCreateDataSource, ErrCreateLayer,   ErrAttributeTypeUnsupported, ErrAttributeCreationFailed, ErrProjection, ErrFeatureWriteFailed,   ErrInvalidLayer, Canceled }
Public Types inherited from QgsFeatureSink
enum	Flag { FastInsert = 1 << 1 }
	Flags controlling how features are added to a sink. More...
enum	SinkFlag { RegeneratePrimaryKey = 1 << 1 }
	Flags that can be set on a QgsFeatureSink. More...

Public Member Functions
	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. More...
	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. More...
	QgsVectorFileWriter (const QgsVectorFileWriter &rh)=delete
	QgsVectorFileWriter cannot be copied. More...
	~QgsVectorFileWriter () override
	Close opened shapefile for writing. More...
bool	addFeature (QgsFeature &feature, QgsFeatureSink::Flags flags=nullptr) override
	Adds a single feature to the sink. More...
bool	addFeatures (QgsFeatureList &features, QgsFeatureSink::Flags flags=nullptr) override
	Adds a list of features to the sink. More...
bool	addFeatureWithStyle (QgsFeature &feature, QgsFeatureRenderer *renderer, QgsUnitTypes::DistanceUnit outputUnit=QgsUnitTypes::DistanceMeters)
	Adds a feature to the currently opened data source, using the style from a specified renderer. More...
QMap< int, int >	attrIdxToOgrIdx ()
QString	errorMessage ()
	Retrieves error message. More...
QgsVectorFileWriter::WriterError	hasError ()
	Checks whether there were any errors in constructor. More...
QgsVectorFileWriter &	operator= (const QgsVectorFileWriter &rh)=delete
	QgsVectorFileWriter cannot be copied. More...
void	setSymbologyExport (QgsVectorFileWriter::SymbologyExport symExport)
void	setSymbologyScale (double scale)
	Set reference scale for output. More...
QgsVectorFileWriter::SymbologyExport	symbologyExport () const
double	symbologyScale () const
	Returns the reference scale for output. More...
Public Member Functions inherited from QgsFeatureSink
virtual	~QgsFeatureSink ()=default
virtual bool	addFeatures (QgsFeatureIterator &iterator, QgsFeatureSink::Flags flags=nullptr)
	Adds all features from the specified iterator to the sink. More...
virtual bool	flushBuffer ()
	Flushes any internal buffer which may exist in the sink, causing any buffered features to be added to the sink's destination. More...

Static Public Member Functions
static bool	areThereNewFieldsToCreate (const QString &datasetName, const QString &layerName, QgsVectorLayer *layer, const QgsAttributeList &attributes)
	Returns whether there are among the attributes specified some that do not exist yet in the layer. More...
static QString	convertCodecNameForEncodingOption (const QString &codecName)
	Converts codec name to string passed to ENCODING layer creation option of OGR Shapefile. More...
static QStringList	defaultDatasetOptions (const QString &driverName)
	Returns a list of the default dataset options for a specified driver. More...
static QStringList	defaultLayerOptions (const QString &driverName)
	Returns a list of the default layer options for a specified driver. More...
static bool	deleteShapeFile (const QString &fileName)
	Delete a shapefile (and its accompanying shx / dbf / prf) More...
static QString	driverForExtension (const QString &extension)
	Returns the OGR driver name for a specified file extension. More...
static bool	driverMetadata (const QString &driverName, MetaData &driverMetadata)
static QgsVectorFileWriter::EditionCapabilities	editionCapabilities (const QString &datasetName)
	Returns edition capabilities for an existing dataset name. More...
static QString	fileFilterString (VectorFormatOptions options=SortRecommended)
	Returns filter string that can be used for dialogs. More...
static QString	filterForDriver (const QString &driverName)
	Creates a filter for an OGR driver key. More...
static QList< QgsVectorFileWriter::DriverDetails >	ogrDriverList (VectorFormatOptions options=SortRecommended)
	Returns the driver list that can be used for dialogs. More...
static OGRwkbGeometryType	ogrTypeFromWkbType (QgsWkbTypes::Type type)
	Gets the ogr geometry type from an internal QGIS wkb type enum. More...
static QList< QgsVectorFileWriter::FilterFormatDetails >	supportedFiltersAndFormats (VectorFormatOptions options=SortRecommended)
	Returns a list or pairs, with format filter string as first element and OGR format key as second element. More...
static QStringList	supportedFormatExtensions (VectorFormatOptions options=SortRecommended)
	Returns a list of file extensions for supported formats, e.g "shp", "gpkg". More...
static bool	supportsFeatureStyles (const QString &driverName)
	Returns true if the specified driverName supports feature styles. More...
static bool	targetLayerExists (const QString &datasetName, const QString &layerName)
	Returns whether the target layer already exists. More...
static QgsVectorFileWriter::WriterError	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)
	Write contents of vector layer to an (OGR supported) vector format. More...
static QgsVectorFileWriter::WriterError	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)
	Writes a layer out to a vector file. More...
static QgsVectorFileWriter::WriterError	writeAsVectorFormat (QgsVectorLayer *layer, const QString &fileName, const QgsVectorFileWriter::SaveVectorOptions &options, QString *newFilename=nullptr, QString *errorMessage=nullptr, QString *newLayer=nullptr)
	Writes a layer out to a vector file. More...

Protected Member Functions
OGRGeometryH	createEmptyGeometry (QgsWkbTypes::Type wkbType)

Protected Attributes
QMap< int, int >	mAttrIdxToOgrIdx
	Map attribute indizes to OGR field indexes. More...
QTextCodec *	mCodec = nullptr
gdal::ogr_datasource_unique_ptr	mDS
WriterError	mError
	Contains error value if construction was not successful. More...
QString	mErrorMessage
QgsFields	mFields
FieldValueConverter *	mFieldValueConverter = nullptr
	Field value converter. More...
OGRLayerH	mLayer = nullptr
QString	mOgrDriverName
OGRSpatialReferenceH	mOgrRef = nullptr
QMap< QgsSymbolLayer *, QString >	mSymbolLayerTable
SymbologyExport	mSymbologyExport
double	mSymbologyScale
	Scale for symbology export (e.g. for symbols units in map units) More...
QgsWkbTypes::Type	mWkbType
	Geometry type which is being used. More...

Friends
class	QgsVectorFileWriterTask
class	TestQgsVectorFileWriter

Detailed Description

A convenience class for writing vector files to disk.

There are two possibilities how to use this class:

1. static call to QgsVectorFileWriter::writeAsVectorFormat(...) which saves the whole vector layer
2. create an instance of the class and issue calls to addFeature(...)

Definition at line 45 of file qgsvectorfilewriter.h.

Member Enumeration Documentation

enum QgsVectorFileWriter::ActionOnExistingFile

Combination of CanAddNewLayer, CanAppendToExistingLayer, CanAddNewFieldsToExistingLayer or CanDeleteLayer.

Since

QGIS 3.0 Enumeration to describe how to handle existing files

QGIS 3.0

Enumerator
CreateOrOverwriteFile	Create or overwrite file.
CreateOrOverwriteLayer	Create or overwrite layer.
AppendToLayerNoNewFields	Append features to existing layer, but do not create new fields.
AppendToLayerAddFields	Append features to existing layer, and create new fields if needed.

Definition at line 261 of file qgsvectorfilewriter.h.

enum QgsVectorFileWriter::EditionCapability

Edition capability flags.

Since

QGIS 3.0

Enumerator
CanAddNewLayer	Flag to indicate that a new layer can be added to the dataset.
CanAppendToExistingLayer	Flag to indicate that new features can be added to an existing layer.
CanAddNewFieldsToExistingLayer	Flag to indicate that new fields can be added to an existing layer. Imply CanAppendToExistingLayer.
CanDeleteLayer	Flag to indicate that an existing layer can be deleted.

Definition at line 237 of file qgsvectorfilewriter.h.

enum QgsVectorFileWriter::OptionType

Enumerator
Set
String
Int
Hidden

Definition at line 48 of file qgsvectorfilewriter.h.

enum QgsVectorFileWriter::SymbologyExport

Enumerator
NoSymbology
FeatureSymbology
SymbolLayerSymbology

Definition at line 181 of file qgsvectorfilewriter.h.

enum QgsVectorFileWriter::VectorFormatOption

Options for sorting and filtering vector formats.

Since

QGIS 3.0

Enumerator
SortRecommended	Use recommended sort order, with extremely commonly used formats listed first.
SkipNonSpatialFormats	Filter out any formats which do not have spatial support (e.g. those which cannot save geometries)

Definition at line 193 of file qgsvectorfilewriter.h.

enum QgsVectorFileWriter::WriterError

Enumerator
NoError
ErrDriverNotFound
ErrCreateDataSource
ErrCreateLayer
ErrAttributeTypeUnsupported
ErrAttributeCreationFailed
ErrProjection
ErrFeatureWriteFailed
ErrInvalidLayer
Canceled	Writing was interrupted by manual cancellation.

Definition at line 167 of file qgsvectorfilewriter.h.

Constructor & Destructor Documentation

QgsVectorFileWriter::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.

Definition at line 94 of file qgsvectorfilewriter.cpp.

QgsVectorFileWriter::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.

Parameters

vectorFileName	file name to write to
fileEncoding	encoding to use
fields	fields to write
geometryType	geometry type of output file
srs	spatial reference system of output file
driverName	OGR driver to use
datasourceOptions	list of OGR data source creation options
layerOptions	list of OGR layer creation options
newFilename	potentially modified file name (output parameter)
symbologyExport	symbology to export
fieldValueConverter	field value converter (added in QGIS 2.16)
layerName	layer name. If let empty, it will be derived from the filename (added in QGIS 3.0)
action	action on existing file (added in QGIS 3.0)
newLayer	potentially modified layer name (output parameter) (added in QGIS 3.4)

Note

not available in Python bindings

Definition at line 118 of file qgsvectorfilewriter.cpp.

QgsVectorFileWriter::QgsVectorFileWriter ( const QgsVectorFileWriter &  rh )

delete

QgsVectorFileWriter cannot be copied.

QgsVectorFileWriter::~QgsVectorFileWriter ( )

override

Close opened shapefile for writing.

Definition at line 2399 of file qgsvectorfilewriter.cpp.

Member Function Documentation

bool QgsVectorFileWriter::addFeature ( QgsFeature &  feature, QgsFeatureSink::Flags  flags = nullptr  )

overridevirtual

Adds a single feature to the sink.

Feature addition behavior is controlled by the specified flags.

See also

addFeatures()

Returns

true in case of success and false in case of failure

Reimplemented from QgsFeatureSink.

Definition at line 2064 of file qgsvectorfilewriter.cpp.

bool QgsVectorFileWriter::addFeatures ( QgsFeatureList &  features, QgsFeatureSink::Flags  flags = nullptr  )

overridevirtual

Adds a list of features to the sink.

Feature addition behavior is controlled by the specified flags.

See also

addFeature()

Returns

true in case of success and false in case of failure

Implements QgsFeatureSink.

Definition at line 2069 of file qgsvectorfilewriter.cpp.

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

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

Since

QGIS 3.0

Definition at line 2080 of file qgsvectorfilewriter.cpp.

bool QgsVectorFileWriter::areThereNewFieldsToCreate ( const QString &  datasetName, const QString &  layerName, QgsVectorLayer *  layer, const QgsAttributeList &  attributes  )

static

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

Since

QGIS 3.0

Definition at line 3573 of file qgsvectorfilewriter.cpp.

QMap<int, int> QgsVectorFileWriter::attrIdxToOgrIdx ( )

inline

Note

not available in Python bindings

Definition at line 715 of file qgsvectorfilewriter.h.

QString QgsVectorFileWriter::convertCodecNameForEncodingOption ( const QString &  codecName )

static

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

Definition at line 3182 of file qgsvectorfilewriter.cpp.

OGRGeometryH QgsVectorFileWriter::createEmptyGeometry ( QgsWkbTypes::Type  wkbType )

protected

Note

not available in Python bindings

Definition at line 767 of file qgsvectorfilewriter.cpp.

QStringList QgsVectorFileWriter::defaultDatasetOptions ( const QString &  driverName )

static

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

Parameters

driverName

name of OGR driver

See also

defaultLayerOptions()

Since

QGIS 3.0

Definition at line 2024 of file qgsvectorfilewriter.cpp.

QStringList QgsVectorFileWriter::defaultLayerOptions ( const QString &  driverName )

static

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

Parameters

driverName

name of OGR driver

See also

defaultDatasetOptions()

Since

QGIS 3.0

Definition at line 2033 of file qgsvectorfilewriter.cpp.

bool QgsVectorFileWriter::deleteShapeFile ( const QString &  fileName )

static

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

Parameters

fileName

/path/to/file.shp

Returns

bool true if the file was deleted successfully

Definition at line 2878 of file qgsvectorfilewriter.cpp.

QString QgsVectorFileWriter::driverForExtension ( const QString &  extension )

static

Returns the OGR driver name for a specified file extension.

E.g. the driver name for the ".shp" extension is "ESRI Shapefile". If no suitable drivers are found then an empty string is returned.

Since

QGIS 3.0

Definition at line 3123 of file qgsvectorfilewriter.cpp.

bool QgsVectorFileWriter::driverMetadata ( const QString &  driverName, QgsVectorFileWriter::MetaData &  driverMetadata  )

static

Definition at line 2007 of file qgsvectorfilewriter.cpp.

QgsVectorFileWriter::EditionCapabilities QgsVectorFileWriter::editionCapabilities ( const QString &  datasetName )

static

Returns edition capabilities for an existing dataset name.

Since

QGIS 3.0

Definition at line 3518 of file qgsvectorfilewriter.cpp.

QString QgsVectorFileWriter::errorMessage

(

)

Retrieves error message.

Definition at line 2059 of file qgsvectorfilewriter.cpp.

QString QgsVectorFileWriter::fileFilterString ( VectorFormatOptions  options = SortRecommended )

static

Returns filter string that can be used for dialogs.

The options argument can be used to control the sorting and filtering of returned drivers.

Definition at line 3157 of file qgsvectorfilewriter.cpp.

QString QgsVectorFileWriter::filterForDriver ( const QString &  driverName )

static

Creates a filter for an OGR driver key.

Definition at line 3171 of file qgsvectorfilewriter.cpp.

QgsVectorFileWriter::WriterError QgsVectorFileWriter::hasError

(

)

Checks whether there were any errors in constructor.

Definition at line 2054 of file qgsvectorfilewriter.cpp.

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

static

Returns the driver list that can be used for dialogs.

It contains all OGR drivers plus some additional internal QGIS driver names to distinguish between more supported formats of the same OGR driver.

The returned list consists of structs containing the driver long name (e.g. user-friendly display name for the format) and internal driver short name.

The options argument can be used to control the sorting and filtering of returned drivers.

Definition at line 3029 of file qgsvectorfilewriter.cpp.

OGRwkbGeometryType QgsVectorFileWriter::ogrTypeFromWkbType ( QgsWkbTypes::Type  type )

static

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

Will drop M values and convert Z to 2.5D where required.

Note

not available in Python bindings

Definition at line 2042 of file qgsvectorfilewriter.cpp.

QgsVectorFileWriter& QgsVectorFileWriter::operator= ( const QgsVectorFileWriter &  rh )

delete

QgsVectorFileWriter cannot be copied.

void QgsVectorFileWriter::setSymbologyExport ( QgsVectorFileWriter::SymbologyExport  symExport )

inline

Definition at line 728 of file qgsvectorfilewriter.h.

void QgsVectorFileWriter::setSymbologyScale

(

double

scale

)

Set reference scale for output.

The scale value indicates the scale denominator, e.g. 1000.0 for a 1:1000 map.

See also

symbologyScale()

Since

QGIS 3.0

Definition at line 2904 of file qgsvectorfilewriter.cpp.

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

static

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

The options argument can be used to control the sorting and filtering of returned formats.

See also

supportedFormatExtensions()

Definition at line 2910 of file qgsvectorfilewriter.cpp.

QStringList QgsVectorFileWriter::supportedFormatExtensions ( VectorFormatOptions  options = SortRecommended )

static

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

The options argument can be used to control the sorting and filtering of returned formats.

See also

supportedFiltersAndFormats()

Since

QGIS 3.0

Definition at line 2987 of file qgsvectorfilewriter.cpp.

bool QgsVectorFileWriter::supportsFeatureStyles ( const QString &  driverName )

static

Returns true if the specified driverName supports feature styles.

The driverName argument must be a valid GDAL driver name.

Since

QGIS 3.0

Definition at line 142 of file qgsvectorfilewriter.cpp.

QgsVectorFileWriter::SymbologyExport QgsVectorFileWriter::symbologyExport ( ) const

inline

Definition at line 727 of file qgsvectorfilewriter.h.

double QgsVectorFileWriter::symbologyScale ( ) const

inline

Returns the reference scale for output.

The scale value indicates the scale denominator, e.g. 1000.0 for a 1:1000 map.

See also

setSymbologyScale()

Since

QGIS 3.0

Definition at line 736 of file qgsvectorfilewriter.h.

bool QgsVectorFileWriter::targetLayerExists ( const QString &  datasetName, const QString &  layerName  )

static

Returns whether the target layer already exists.

Since

QGIS 3.0

Definition at line 3557 of file qgsvectorfilewriter.cpp.

QgsVectorFileWriter::WriterError QgsVectorFileWriter::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  )

static

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

Parameters

layer	layer to write
fileName	file name to write to
fileEncoding	encoding to use
destCRS	CRS to reproject exported geometries to, or invalid CRS for no reprojection
driverName	OGR driver to use
onlySelected	write only selected features of layer
errorMessage	pointer to buffer fo error message
datasourceOptions	list of OGR data source creation options
layerOptions	list of OGR layer creation options
skipAttributeCreation	only write geometries
newFilename	QString pointer which will contain the new file name created (in case it is different to fileName).
symbologyExport	symbology to export
symbologyScale	scale of symbology
filterExtent	if not a null pointer, only features intersecting the extent will be saved (added in QGIS 2.4)
overrideGeometryType	set to a valid geometry type to override the default geometry type for the layer. This parameter allows for conversion of geometryless tables to null geometries, etc (added in QGIS 2.14)
forceMulti	set to true to force creation of multi* geometries (added in QGIS 2.14)
includeZ	set to true to include z dimension in output. This option is only valid if overrideGeometryType is set. (added in QGIS 2.14)
attributes	attributes to export (empty means all unless skipAttributeCreation is set)
fieldValueConverter	field value converter (added in QGIS 2.16)
newLayer	QString pointer which will contain the new layer name created (in case it is different to the provided layer name) (added in QGIS 3.4, not available in python)

Definition at line 2418 of file qgsvectorfilewriter.cpp.

QgsVectorFileWriter::WriterError QgsVectorFileWriter::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  )

static

Writes a layer out to a vector file.

Parameters

layer	layer to write
fileName	file name to write to
fileEncoding	encoding to use
ct	coordinate transform to reproject exported geometries with, or invalid transform for no transformation
driverName	OGR driver to use
onlySelected	write only selected features of layer
errorMessage	pointer to buffer fo error message
datasourceOptions	list of OGR data source creation options
layerOptions	list of OGR layer creation options
skipAttributeCreation	only write geometries
newFilename	QString pointer which will contain the new file name created (in case it is different to fileName).
symbologyExport	symbology to export
symbologyScale	scale of symbology
filterExtent	if not a null pointer, only features intersecting the extent will be saved (added in QGIS 2.4)
overrideGeometryType	set to a valid geometry type to override the default geometry type for the layer. This parameter allows for conversion of geometryless tables to null geometries, etc (added in QGIS 2.14)
forceMulti	set to true to force creation of multi* geometries (added in QGIS 2.14)
includeZ	set to true to include z dimension in output. This option is only valid if overrideGeometryType is set. (added in QGIS 2.14)
attributes	attributes to export (empty means all unless skipAttributeCreation is set)
fieldValueConverter	field value converter (added in QGIS 2.16)
newLayer	QString pointer which will contain the new layer name created (in case it is different to the provided layer name) (added in QGIS 3.4, not available in python)

Since

QGIS 2.2

Definition at line 2455 of file qgsvectorfilewriter.cpp.

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

static

Writes a layer out to a vector file.

Parameters

layer	source layer to write
fileName	file name to write to
options	options.
newFilename	QString pointer which will contain the new file name created (in case it is different to fileName).
errorMessage	pointer to buffer fo error message
newLayer	QString pointer which will contain the new layer name created (in case it is different to the provided layer name) (added in QGIS 3.4, not available in python)

Since

QGIS 3.0

Definition at line 2862 of file qgsvectorfilewriter.cpp.

Friends And Related Function Documentation

friend class QgsVectorFileWriterTask

friend

Definition at line 911 of file qgsvectorfilewriter.h.

friend class TestQgsVectorFileWriter

friend

Definition at line 912 of file qgsvectorfilewriter.h.

Member Data Documentation

QMap<int, int> QgsVectorFileWriter::mAttrIdxToOgrIdx

protected

Map attribute indizes to OGR field indexes.

Definition at line 814 of file qgsvectorfilewriter.h.

QTextCodec* QgsVectorFileWriter::mCodec = nullptr

protected

Definition at line 808 of file qgsvectorfilewriter.h.

gdal::ogr_datasource_unique_ptr QgsVectorFileWriter::mDS

protected

Definition at line 798 of file qgsvectorfilewriter.h.

WriterError QgsVectorFileWriter::mError

protected

Contains error value if construction was not successful.

Definition at line 805 of file qgsvectorfilewriter.h.

QString QgsVectorFileWriter::mErrorMessage

protected

Definition at line 806 of file qgsvectorfilewriter.h.

QgsFields QgsVectorFileWriter::mFields

protected

Definition at line 802 of file qgsvectorfilewriter.h.

FieldValueConverter* QgsVectorFileWriter::mFieldValueConverter = nullptr

protected

Field value converter.

Definition at line 826 of file qgsvectorfilewriter.h.

OGRLayerH QgsVectorFileWriter::mLayer = nullptr

protected

Definition at line 799 of file qgsvectorfilewriter.h.

QString QgsVectorFileWriter::mOgrDriverName

protected

Definition at line 823 of file qgsvectorfilewriter.h.

OGRSpatialReferenceH QgsVectorFileWriter::mOgrRef = nullptr

protected

Definition at line 800 of file qgsvectorfilewriter.h.

QMap< QgsSymbolLayer *, QString > QgsVectorFileWriter::mSymbolLayerTable

protected

Definition at line 818 of file qgsvectorfilewriter.h.

SymbologyExport QgsVectorFileWriter::mSymbologyExport

protected

Definition at line 816 of file qgsvectorfilewriter.h.

double QgsVectorFileWriter::mSymbologyScale

protected

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

Definition at line 821 of file qgsvectorfilewriter.h.

QgsWkbTypes::Type QgsVectorFileWriter::mWkbType

protected

Geometry type which is being used.

Definition at line 811 of file qgsvectorfilewriter.h.

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The documentation for this class was generated from the following files:

• /build/qgis-3.4.15+24xenial/src/core/qgsvectorfilewriter.h
• /build/qgis-3.4.15+24xenial/src/core/qgsvectorfilewriter.cpp