QgsVectorFileWriter Class Reference

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

#include <qgsvectorfilewriter.h>

Collaboration diagram for QgsVectorFileWriter:

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

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.

Private Member Functions
void	createSymbolLayerTable (QgsVectorLayer *vl, const QgsCoordinateTransform *ct, OGRDataSourceH ds)
OGRFeatureH	createFeature (QgsFeature &feature)
bool	writeFeature (OGRLayerH layer, OGRFeatureH feature)
WriterError	exportFeaturesSymbolLevels (QgsVectorLayer *layer, QgsFeatureIterator &fit, const QgsCoordinateTransform *ct, QString *errorMessage=0)
	Writes features considering symbol level order.
double	mmScaleFactor (double scaleDenominator, QgsSymbolV2::OutputUnit symbolUnits, QGis::UnitType mapUnits)
double	mapUnitScaleFactor (double scaleDenominator, QgsSymbolV2::OutputUnit symbolUnits, QGis::UnitType mapUnits)
QgsRenderContext	renderContext () const
void	startRender (QgsVectorLayer *vl) const
void	stopRender (QgsVectorLayer *vl) const
QgsFeatureRendererV2 *	symbologyRenderer (QgsVectorLayer *vl) const
void	addRendererAttributes (QgsVectorLayer *vl, QgsAttributeList &attList)
	Adds attributes needed for classification.

Static Private Member Functions
static bool	driverMetadata (QString driverName, QString &longName, QString &trLongName, QString &glob, QString &ext)

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.

Definition at line 42 of file qgsvectorfilewriter.h.

Member Enumeration Documentation

enum QgsVectorFileWriter::SymbologyExport

Enumerator:

NoSymbology
FeatureSymbology
SymbolLayerSymbology

Definition at line 60 of file qgsvectorfilewriter.h.

enum QgsVectorFileWriter::WriterError

Enumerator:

NoError
ErrDriverNotFound
ErrCreateDataSource
ErrCreateLayer
ErrAttributeTypeUnsupported
ErrAttributeCreationFailed
ErrProjection
ErrFeatureWriteFailed
ErrInvalidLayer

Definition at line 46 of file qgsvectorfilewriter.h.

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

Definition at line 56 of file qgsvectorfilewriter.cpp.

References convertCodecNameForEncodingOption(), QgsFields::count(), createEmptyGeometry(), deleteShapeFile(), driverMetadata(), ErrAttributeCreationFailed, ErrAttributeTypeUnsupported, ErrCreateDataSource, ErrCreateLayer, ErrDriverNotFound, QgsField::length(), QgsMessageLog::logMessage(), mAttrIdxToOgrIdx, mCodec, mDS, mError, mErrorMessage, mFields, mGeom, mLayer, mWkbType, QgsField::name(), QgsField::precision(), QgsDebugMsg, QgsApplication::registerOgrDrivers(), QgsFields::size(), TO8F, QgsCoordinateReferenceSystem::toWkt(), tr, QgsField::type(), and QGis::WKBNoGeometry.

Referenced by writeAsVectorFormat().

QgsVectorFileWriter::~QgsVectorFileWriter

(

)

close opened shapefile for writing

Definition at line 719 of file qgsvectorfilewriter.cpp.

References mDS, and mGeom.

Member Function Documentation

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

add feature to the currently opened shapefile

Definition at line 498 of file qgsvectorfilewriter.cpp.

References createFeature(), FeatureSymbology, mapUnitScaleFactor(), mLayer, mmScaleFactor(), mSymbologyExport, mSymbologyScaleDenominator, NoSymbology, SymbolLayerSymbology, QgsFeatureRendererV2::symbolsForFeature(), and writeFeature().

Referenced by QgsGeometryAnalyzer::addEventLayerFeature(), QgsGeometryAnalyzer::bufferFeature(), QgsGeometryAnalyzer::centroidFeature(), QgsOverlayAnalyzer::intersectFeature(), QgsGeometryAnalyzer::simplifyFeature(), and writeAsVectorFormat().

void QgsVectorFileWriter::addRendererAttributes ( QgsVectorLayer *  vl, QgsAttributeList &  attList  )

private

Adds attributes needed for classification.

Definition at line 1559 of file qgsvectorfilewriter.cpp.

References QgsVectorLayer::fieldNameIndex(), symbologyRenderer(), and QgsFeatureRendererV2::usedAttributes().

Referenced by writeAsVectorFormat().

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

inline

Note

not available in python bindings

Definition at line 141 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 1096 of file qgsvectorfilewriter.cpp.

Referenced by QgsVectorFileWriter().

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

protected

Note

not available in python bindings

Definition at line 482 of file qgsvectorfilewriter.cpp.

Referenced by createFeature(), and QgsVectorFileWriter().

OGRFeatureH QgsVectorFileWriter::createFeature ( QgsFeature &  feature )

private

Definition at line 562 of file qgsvectorfilewriter.cpp.

References QgsGeometry::asWkb(), QgsFeature::attribute(), QgsGeometry::convertToMultiType(), QgsFields::count(), createEmptyGeometry(), ErrFeatureWriteFailed, FID_TO_NUMBER, QgsFeature::geometry(), QgsFeature::id(), QgsMessageLog::logMessage(), mAttrIdxToOgrIdx, MathUtils::max(), mCodec, mError, mErrorMessage, mFields, mGeom, mLayer, mWkbType, QgsDebugMsg, QGis::singleType(), tr, QGis::WKBNoGeometry, QgsGeometry::wkbSize(), and QgsGeometry::wkbType().

Referenced by addFeature(), and exportFeaturesSymbolLevels().

void QgsVectorFileWriter::createSymbolLayerTable ( QgsVectorLayer *  vl, const QgsCoordinateTransform *  ct, OGRDataSourceH  ds  )

private

Definition at line 1293 of file qgsvectorfilewriter.cpp.

References QgsMapLayer::crs(), QgsCoordinateTransform::destCRS(), QgsCoordinateReferenceSystem::mapUnits(), mapUnitScaleFactor(), mmScaleFactor(), mSymbologyScaleDenominator, QgsVectorLayer::rendererV2(), and QgsFeatureRendererV2::symbols().

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

Definition at line 945 of file qgsvectorfilewriter.cpp.

References file, and QgsDebugMsg.

Referenced by QgsVectorFileWriter().

bool QgsVectorFileWriter::driverMetadata ( QString  driverName, QString &  longName, QString &  trLongName, QString &  glob, QString &  ext  )

staticprivate

Definition at line 1113 of file qgsvectorfilewriter.cpp.

References tr.

Referenced by filterForDriver(), ogrDriverList(), and QgsVectorFileWriter().

QString QgsVectorFileWriter::errorMessage

(

)

retrieves error message

Note

added in 1.5

Definition at line 493 of file qgsvectorfilewriter.cpp.

References mErrorMessage.

Referenced by writeAsVectorFormat().

QgsVectorFileWriter::WriterError QgsVectorFileWriter::exportFeaturesSymbolLevels ( QgsVectorLayer *  layer, QgsFeatureIterator &  fit, const QgsCoordinateTransform *  ct, QString *  errorMessage = 0  )

private

Writes features considering symbol level order.

Definition at line 1340 of file qgsvectorfilewriter.cpp.

References createFeature(), QgsMapLayer::crs(), QgsCoordinateTransform::destCRS(), ErrFeatureWriteFailed, ErrProjection, QgsFeature::geometry(), QgsSymbolV2LevelItem::layer(), QgsCoordinateReferenceSystem::mapUnits(), mapUnitScaleFactor(), mLayer, mmScaleFactor(), mSymbologyScaleDenominator, QgsFeatureIterator::nextFeature(), NoError, QgsVectorLayer::rendererV2(), QgsSymbolLayerV2::renderingPass(), startRender(), stopRender(), QgsSymbolV2LevelItem::symbol(), QgsFeatureRendererV2::symbolForFeature(), QgsSymbolV2::symbolLayer(), QgsSymbolV2::symbolLayerCount(), QgsFeatureRendererV2::symbols(), tr, QgsGeometry::transform(), QgsLogger::warning(), QgsException::what(), and writeFeature().

Referenced by writeAsVectorFormat().

QString QgsVectorFileWriter::fileFilterString ( )

static

Returns filter string that can be used for dialogs.

Definition at line 1069 of file qgsvectorfilewriter.cpp.

References supportedFiltersAndFormats().

QString QgsVectorFileWriter::filterForDriver ( const QString &  driverName )

static

Creates a filter for an OGR driver key.

Definition at line 1084 of file qgsvectorfilewriter.cpp.

References driverMetadata().

Referenced by supportedFiltersAndFormats().

QgsVectorFileWriter::WriterError QgsVectorFileWriter::hasError

(

)

checks whether there were any errors in constructor

Definition at line 488 of file qgsvectorfilewriter.cpp.

References mError.

Referenced by writeAsVectorFormat().

double QgsVectorFileWriter::mapUnitScaleFactor ( double  scaleDenominator, QgsSymbolV2::OutputUnit  symbolUnits, QGis::UnitType  mapUnits  )

private

Definition at line 1498 of file qgsvectorfilewriter.cpp.

References QgsSymbolV2::MapUnit, QGis::Meters, and QgsSymbolV2::MM.

Referenced by addFeature(), createSymbolLayerTable(), and exportFeaturesSymbolLevels().

double QgsVectorFileWriter::mmScaleFactor ( double  scaleDenominator, QgsSymbolV2::OutputUnit  symbolUnits, QGis::UnitType  mapUnits  )

private

Definition at line 1480 of file qgsvectorfilewriter.cpp.

References QGis::Meters, and QgsSymbolV2::MM.

Referenced by addFeature(), createSymbolLayerTable(), and exportFeaturesSymbolLevels().

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

Definition at line 997 of file qgsvectorfilewriter.cpp.

References driverMetadata(), QgsApplication::registerOgrDrivers(), and TO8F.

QgsRenderContext QgsVectorFileWriter::renderContext ( ) const

private

Definition at line 1514 of file qgsvectorfilewriter.cpp.

References mSymbologyScaleDenominator, and QgsRenderContext::setRendererScale().

Referenced by startRender(), and stopRender().

void QgsVectorFileWriter::setSymbologyExport ( SymbologyExport  symExport )

inline

Definition at line 153 of file qgsvectorfilewriter.h.

void QgsVectorFileWriter::setSymbologyScaleDenominator ( double  d )

inline

Definition at line 156 of file qgsvectorfilewriter.h.

Referenced by writeAsVectorFormat().

void QgsVectorFileWriter::startRender ( QgsVectorLayer *  vl ) const

private

Definition at line 1521 of file qgsvectorfilewriter.cpp.

References renderContext(), QgsFeatureRendererV2::startRender(), and symbologyRenderer().

Referenced by exportFeaturesSymbolLevels(), and writeAsVectorFormat().

void QgsVectorFileWriter::stopRender ( QgsVectorLayer *  vl ) const

private

Definition at line 1533 of file qgsvectorfilewriter.cpp.

References renderContext(), QgsFeatureRendererV2::stopRender(), and symbologyRenderer().

Referenced by exportFeaturesSymbolLevels(), and writeAsVectorFormat().

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

static

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

Definition at line 970 of file qgsvectorfilewriter.cpp.

References filterForDriver(), and QgsApplication::registerOgrDrivers().

Referenced by fileFilterString().

SymbologyExport QgsVectorFileWriter::symbologyExport ( ) const

inline

Definition at line 152 of file qgsvectorfilewriter.h.

Referenced by writeAsVectorFormat().

QgsFeatureRendererV2 * QgsVectorFileWriter::symbologyRenderer ( QgsVectorLayer *  vl ) const

private

Definition at line 1545 of file qgsvectorfilewriter.cpp.

References mSymbologyExport, NoSymbology, and QgsVectorLayer::rendererV2().

Referenced by addRendererAttributes(), startRender(), and stopRender().

double QgsVectorFileWriter::symbologyScaleDenominator ( ) const

inline

Definition at line 155 of file qgsvectorfilewriter.h.

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  )

static

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

@note: this method was added in version 1.5

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

Definition at line 733 of file qgsvectorfilewriter.cpp.

References addFeature(), addRendererAttributes(), QgsFeatureRendererV2::capabilities(), QgsMapLayer::crs(), QgsCoordinateTransform::destCRS(), ErrFeatureWriteFailed, ErrInvalidLayer, errorMessage(), ErrProjection, exportFeaturesSymbolLevels(), QgsFeature::geometry(), QgsVectorLayer::getFeatures(), hasError(), QgsFeature::id(), QgsFeature::initAttributes(), QgsCoordinateReferenceSystem::isValid(), QgsCoordinateReferenceSystem::mapUnits(), mLayer, QgsFeatureIterator::nextFeature(), NoError, QgsFeatureRequest::NoGeometry, NoSymbology, QgsVectorLayer::pendingAllAttributesList(), QgsVectorLayer::pendingFields(), QgsDebugMsg, QgsVectorFileWriter(), QgsVectorLayer::rendererV2(), QgsVectorLayer::selectedFeaturesIds(), QgsFeatureRequest::setFlags(), QgsFeatureRequest::setSubsetOfAttributes(), setSymbologyScaleDenominator(), startRender(), stopRender(), SymbolLayerSymbology, QgsFeatureRendererV2::SymbolLevels, symbologyExport(), tr, QgsGeometry::transform(), QgsFeatureRendererV2::usingSymbolLevels(), QgsLogger::warning(), QgsException::what(), QGis::WKBNoGeometry, and QgsVectorLayer::wkbType().

bool QgsVectorFileWriter::writeFeature ( OGRLayerH  layer, OGRFeatureH  feature  )

private

Definition at line 706 of file qgsvectorfilewriter.cpp.

References ErrFeatureWriteFailed, QgsMessageLog::logMessage(), mError, mErrorMessage, and tr.

Referenced by addFeature(), and exportFeaturesSymbolLevels().

Member Data Documentation

QMap<int, int> QgsVectorFileWriter::mAttrIdxToOgrIdx

protected

map attribute indizes to OGR field indexes

Definition at line 178 of file qgsvectorfilewriter.h.

Referenced by createFeature(), and QgsVectorFileWriter().

QTextCodec* QgsVectorFileWriter::mCodec

protected

Definition at line 172 of file qgsvectorfilewriter.h.

Referenced by createFeature(), and QgsVectorFileWriter().

OGRDataSourceH QgsVectorFileWriter::mDS

protected

Definition at line 162 of file qgsvectorfilewriter.h.

Referenced by QgsVectorFileWriter(), and ~QgsVectorFileWriter().

WriterError QgsVectorFileWriter::mError

protected

contains error value if construction was not successful

Definition at line 169 of file qgsvectorfilewriter.h.

Referenced by createFeature(), hasError(), QgsVectorFileWriter(), and writeFeature().

QString QgsVectorFileWriter::mErrorMessage

protected

Definition at line 170 of file qgsvectorfilewriter.h.

Referenced by createFeature(), errorMessage(), QgsVectorFileWriter(), and writeFeature().

QgsFields QgsVectorFileWriter::mFields

protected

Definition at line 166 of file qgsvectorfilewriter.h.

Referenced by createFeature(), and QgsVectorFileWriter().

OGRGeometryH QgsVectorFileWriter::mGeom

protected

Definition at line 164 of file qgsvectorfilewriter.h.

Referenced by createFeature(), QgsVectorFileWriter(), and ~QgsVectorFileWriter().

OGRLayerH QgsVectorFileWriter::mLayer

protected

Definition at line 163 of file qgsvectorfilewriter.h.

Referenced by addFeature(), createFeature(), exportFeaturesSymbolLevels(), QgsVectorFileWriter(), and writeAsVectorFormat().

SymbologyExport QgsVectorFileWriter::mSymbologyExport

protected

Definition at line 180 of file qgsvectorfilewriter.h.

Referenced by addFeature(), and symbologyRenderer().

double QgsVectorFileWriter::mSymbologyScaleDenominator

protected

Scale for symbology export (e.g.

for symbols units in map units)

Definition at line 187 of file qgsvectorfilewriter.h.

Referenced by addFeature(), createSymbolLayerTable(), exportFeaturesSymbolLevels(), and renderContext().

QGis::WkbType QgsVectorFileWriter::mWkbType

protected

geometry type which is being used

Definition at line 175 of file qgsvectorfilewriter.h.

Referenced by createFeature(), and QgsVectorFileWriter().

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

• /tmp/buildd/qgis-2.0.1/src/core/qgsvectorfilewriter.h
• /tmp/buildd/qgis-2.0.1/src/core/qgsvectorfilewriter.cpp