QgsVectorFileWriter Class Reference

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

#include <qgsvectorfilewriter.h>

Classes
class	BoolOption
class	HiddenOption
class	IntOption
struct	MetaData
class	Option
class	SetOption
class	StringOption

Public Types
enum	OptionType { Set, String, Int, Hidden }
enum	WriterError {   NoError = 0, ErrDriverNotFound, ErrCreateDataSource, ErrCreateLayer,   ErrAttributeTypeUnsupported, ErrAttributeCreationFailed, ErrProjection, ErrFeatureWriteFailed,   ErrInvalidLayer }
enum	SymbologyExport { NoSymbology = 0, FeatureSymbology, SymbolLayerSymbology }

Public Member Functions
	QgsVectorFileWriter (const QString &vectorFileName, const QString &fileEncoding, const QgsFields &fields, QGis::WkbType geometryType, const QgsCoordinateReferenceSystem *srs, const QString &driverName="ESRI Shapefile", const QStringList &datasourceOptions=QStringList(), const QStringList &layerOptions=QStringList(), QString *newFilename=0, SymbologyExport symbologyExport=NoSymbology)
	create shapefile and initialize it
WriterError	hasError ()
	checks whether there were any errors in constructor
QString	errorMessage ()
	retrieves error message
bool	addFeature (QgsFeature &feature, QgsFeatureRendererV2 *renderer=0, QGis::UnitType outputUnit=QGis::Meters)
	add feature to the currently opened shapefile
QMap< int, int >	attrIdxToOgrIdx ()
	~QgsVectorFileWriter ()
	close opened shapefile for writing
SymbologyExport	symbologyExport () const
void	setSymbologyExport (SymbologyExport symExport)
double	symbologyScaleDenominator () const
void	setSymbologyScaleDenominator (double d)

Static Public Member Functions
static WriterError	writeAsVectorFormat (QgsVectorLayer *layer, const QString &fileName, const QString &fileEncoding, const QgsCoordinateReferenceSystem *destCRS, const QString &driverName="ESRI Shapefile", bool onlySelected=false, QString *errorMessage=0, const QStringList &datasourceOptions=QStringList(), const QStringList &layerOptions=QStringList(), bool skipAttributeCreation=false, QString *newFilename=0, SymbologyExport symbologyExport=NoSymbology, double symbologyScale=1.0, const QgsRectangle *filterExtent=0)
	Write contents of vector layer to an (OGR supported) vector formt.
static WriterError	writeAsVectorFormat (QgsVectorLayer *layer, const QString &fileName, const QString &fileEncoding, const QgsCoordinateTransform *ct, const QString &driverName="ESRI Shapefile", bool onlySelected=false, QString *errorMessage=0, const QStringList &datasourceOptions=QStringList(), const QStringList &layerOptions=QStringList(), bool skipAttributeCreation=false, QString *newFilename=0, SymbologyExport symbologyExport=NoSymbology, double symbologyScale=1.0, const QgsRectangle *filterExtent=0)
static QMap< QString, QString >	supportedFiltersAndFormats ()
	Returns map with format filter string as key and OGR format key as value.
static QMap< QString, QString >	ogrDriverList ()
	Returns driver list that can be used for dialogs.
static QString	fileFilterString ()
	Returns filter string that can be used for dialogs.
static QString	filterForDriver (const QString &driverName)
	Creates a filter for an OGR driver key.
static QString	convertCodecNameForEncodingOption (const QString &codecName)
	Converts codec name to string passed to ENCODING layer creation option of OGR Shapefile.
static bool	deleteShapeFile (QString theFileName)
	Delete a shapefile (and its accompanying shx / dbf / prf)
static bool	driverMetadata (const QString &driverName, MetaData &driverMetadata)

Protected Member Functions
OGRGeometryH	createEmptyGeometry (QGis::WkbType wkbType)

Protected Attributes
OGRDataSourceH	mDS
OGRLayerH	mLayer
OGRGeometryH	mGeom
QgsFields	mFields
WriterError	mError
	contains error value if construction was not successful
QString	mErrorMessage
QTextCodec *	mCodec
QGis::WkbType	mWkbType
	geometry type which is being used
QMap< int, int >	mAttrIdxToOgrIdx
	map attribute indizes to OGR field indexes
SymbologyExport	mSymbologyExport
double	mSymbologyScaleDenominator
	Scale for symbology export (e.g.

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::writeAsShapefile(...) which saves the whole vector layer
2. create an instance of the class and issue calls to addFeature(...)

Currently supports only writing to shapefiles, but shouldn't be a problem to add capability to support other OGR-writable formats.

Member Enumeration Documentation

enum QgsVectorFileWriter::OptionType

Enumerator:

Set
String
Int
Hidden

enum QgsVectorFileWriter::SymbologyExport

Enumerator:

NoSymbology
FeatureSymbology
SymbolLayerSymbology

enum QgsVectorFileWriter::WriterError

Enumerator:

NoError
ErrDriverNotFound
ErrCreateDataSource
ErrCreateLayer
ErrAttributeTypeUnsupported
ErrAttributeCreationFailed
ErrProjection
ErrFeatureWriteFailed
ErrInvalidLayer

Constructor & Destructor Documentation

QgsVectorFileWriter::QgsVectorFileWriter	(	const QString &	vectorFileName,
		const QString &	fileEncoding,
		const QgsFields &	fields,
		QGis::WkbType	geometryType,
		const QgsCoordinateReferenceSystem *	srs,
		const QString &	driverName = "ESRI Shapefile",
		const QStringList &	datasourceOptions = QStringList(),
		const QStringList &	layerOptions = QStringList(),
		QString *	newFilename = 0,
		SymbologyExport	symbologyExport = NoSymbology
	)

create shapefile and initialize it

QgsVectorFileWriter::~QgsVectorFileWriter

(

)

close opened shapefile for writing

Member Function Documentation

bool QgsVectorFileWriter::addFeature	(	QgsFeature &	feature,
		QgsFeatureRendererV2 *	renderer = 0,
		QGis::UnitType	outputUnit = QGis::Meters
	)

add feature to the currently opened shapefile

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

inline

Note

not available in python bindings

QString QgsVectorFileWriter::convertCodecNameForEncodingOption ( const QString &  codecName )

static

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

OGRGeometryH QgsVectorFileWriter::createEmptyGeometry ( QGis::WkbType  wkbType )

protected

Note

not available in python bindings

bool QgsVectorFileWriter::deleteShapeFile ( QString  theFileName )

static

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

Parameters

theFileName

/path/to/file.shp

Returns

bool true if the file was deleted successfully

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

static

QString QgsVectorFileWriter::errorMessage

(

)

retrieves error message

QString QgsVectorFileWriter::fileFilterString ( )

static

Returns filter string that can be used for dialogs.

QString QgsVectorFileWriter::filterForDriver ( const QString &  driverName )

static

Creates a filter for an OGR driver key.

QgsVectorFileWriter::WriterError QgsVectorFileWriter::hasError

(

)

checks whether there were any errors in constructor

QMap< QString, QString > QgsVectorFileWriter::ogrDriverList ( )

static

Returns driver list that can be used for dialogs.

It contains all OGR drivers

• some additional internal QGIS driver names to distinguish between more supported formats of the same OGR driver

void QgsVectorFileWriter::setSymbologyExport ( SymbologyExport  symExport )

inline

void QgsVectorFileWriter::setSymbologyScaleDenominator ( double  d )

inline

QMap< QString, QString > QgsVectorFileWriter::supportedFiltersAndFormats ( )

static

Returns map with format filter string as key and OGR format key as value.

SymbologyExport QgsVectorFileWriter::symbologyExport ( ) const

inline

double QgsVectorFileWriter::symbologyScaleDenominator ( ) const

inline

QgsVectorFileWriter::WriterError QgsVectorFileWriter::writeAsVectorFormat ( QgsVectorLayer *  layer, const QString &  fileName, const QString &  fileEncoding, const QgsCoordinateReferenceSystem *  destCRS, const QString &  driverName = "ESRI Shapefile", bool  onlySelected = false, QString *  errorMessage = 0, const QStringList &  datasourceOptions = QStringList(), const QStringList &  layerOptions = QStringList(), bool  skipAttributeCreation = false, QString *  newFilename = 0, SymbologyExport  symbologyExport = NoSymbology, double  symbologyScale = 1.0, const QgsRectangle *  filterExtent = 0  )

static

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

Parameters

layer	layer to write
fileName	file name to write to
fileEncoding	encoding to use
destCRS	pointer to CRS to reproject exported geometries to
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

QgsVectorFileWriter::WriterError QgsVectorFileWriter::writeAsVectorFormat ( QgsVectorLayer *  layer, const QString &  fileName, const QString &  fileEncoding, const QgsCoordinateTransform *  ct, const QString &  driverName = "ESRI Shapefile", bool  onlySelected = false, QString *  errorMessage = 0, const QStringList &  datasourceOptions = QStringList(), const QStringList &  layerOptions = QStringList(), bool  skipAttributeCreation = false, QString *  newFilename = 0, SymbologyExport  symbologyExport = NoSymbology, double  symbologyScale = 1.0, const QgsRectangle *  filterExtent = 0  )

static

Note

added in v2.2

Member Data Documentation

QMap<int, int> QgsVectorFileWriter::mAttrIdxToOgrIdx

protected

map attribute indizes to OGR field indexes

QTextCodec* QgsVectorFileWriter::mCodec

protected

OGRDataSourceH QgsVectorFileWriter::mDS

protected

WriterError QgsVectorFileWriter::mError

protected

contains error value if construction was not successful

QString QgsVectorFileWriter::mErrorMessage

protected

QgsFields QgsVectorFileWriter::mFields

protected

OGRGeometryH QgsVectorFileWriter::mGeom

protected

OGRLayerH QgsVectorFileWriter::mLayer

protected

SymbologyExport QgsVectorFileWriter::mSymbologyExport

protected

double QgsVectorFileWriter::mSymbologyScaleDenominator

protected

Scale for symbology export (e.g.

for symbols units in map units)

QGis::WkbType QgsVectorFileWriter::mWkbType

protected

geometry type which is being used

---

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

• /tmp/buildd/qgis-2.6.0+wheezy1/src/core/qgsvectorfilewriter.h
• /tmp/buildd/qgis-2.6.0+wheezy1/src/core/qgsvectorfilewriter.cpp