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

#include <qgsvectorfilewriter.h>

Collaboration diagram for QgsVectorFileWriter:

Public Types
enum	SymbologyExport { NoSymbology = 0, FeatureSymbology, SymbolLayerSymbology }
enum	WriterError { NoError = 0, ErrDriverNotFound, ErrCreateDataSource, ErrCreateLayer, ErrAttributeTypeUnsupported, ErrAttributeCreationFailed, ErrProjection, ErrFeatureWriteFailed, ErrInvalidLayer }
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
	~QgsVectorFileWriter ()
	close opened shapefile for writing
bool	addFeature (QgsFeature &feature, QgsFeatureRendererV2 *renderer=0, QGis::UnitType outputUnit=QGis::Meters)
	add feature to the currently opened shapefile
QMap< int, int >	attrIdxToOgrIdx ()
QString	errorMessage ()
	retrieves error message
WriterError	hasError ()
	checks whether there were any errors in constructor
void	setSymbologyExport (SymbologyExport symExport)
void	setSymbologyScaleDenominator (double d)
SymbologyExport	symbologyExport () const
double	symbologyScaleDenominator () const
Static Public Member Functions
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 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 QMap< QString, QString >	ogrDriverList ()
	Returns driver list that can be used for dialogs.
static QMap< QString, QString >	supportedFiltersAndFormats ()
	Returns map with format filter string as key and OGR format key as value.
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.
Protected Member Functions
OGRGeometryH	createEmptyGeometry (QGis::WkbType wkbType)
Protected Attributes
QMap< int, int >	mAttrIdxToOgrIdx
	map attribute indizes to OGR field indexes
QTextCodec *	mCodec
OGRDataSourceH	mDS
WriterError	mError
	contains error value if construction was not successful
QString	mErrorMessage
QgsFields	mFields
OGRGeometryH	mGeom
OGRLayerH	mLayer
SymbologyExport	mSymbologyExport
double	mSymbologyScaleDenominator
	Scale for symbology export (e.g.
QGis::WkbType	mWkbType
	geometry type which is being used
Private Member Functions
void	addRendererAttributes (QgsVectorLayer *vl, QgsAttributeList &attList)
	Adds attributes needed for classification.
OGRFeatureH	createFeature (QgsFeature &feature)
void	createSymbolLayerTable (QgsVectorLayer vl, const QgsCoordinateTransform ct, OGRDataSourceH ds)
WriterError	exportFeaturesSymbolLevels (QgsVectorLayer layer, QgsFeatureIterator &fit, const QgsCoordinateTransform ct, QString *errorMessage=0)
	Writes features considering symbol level order.
double	mapUnitScaleFactor (double scaleDenominator, QgsSymbolV2::OutputUnit symbolUnits, QGis::UnitType mapUnits)
double	mmScaleFactor (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
bool	writeFeature (OGRLayerH layer, OGRFeatureH feature)
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(), mAttrIdxToOgrIdx, mCodec, mDS, mError, mErrorMessage, mFields, mGeom, mLayer, mWkbType, QgsField::name(), QgsField::precision(), QgsDebugMsg, QgsApplication::registerOgrDrivers(), QgsFields::size(), TO8, TO8F, QgsCoordinateReferenceSystem::toWkt(), tr, QgsField::type(), and QGis::WKBNoGeometry.

Referenced by writeAsVectorFormat().

QgsVectorFileWriter::~QgsVectorFileWriter ( )

close opened shapefile for writing

Definition at line 671 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 450 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 1482 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 1026 of file qgsvectorfilewriter.cpp.

Referenced by QgsVectorFileWriter().

OGRGeometryH QgsVectorFileWriter::createEmptyGeometry ( QGis::WkbType wkbType ) [protected]

Note:: not available in python bindings

Definition at line 434 of file qgsvectorfilewriter.cpp.

Referenced by createFeature(), and QgsVectorFileWriter().

OGRFeatureH QgsVectorFileWriter::createFeature ( QgsFeature & feature ) [private]

Definition at line 514 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 1216 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 880 of file qgsvectorfilewriter.cpp.

References file, and QgsDebugMsg.

Referenced by QgsVectorFileWriter().

bool QgsVectorFileWriter::driverMetadata	(	QString	driverName,
		QString &	longName,
		QString &	trLongName,
		QString &	glob,
		QString &	ext
	)		`[static, private]`

Definition at line 1043 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 445 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 1263 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 999 of file qgsvectorfilewriter.cpp.

References supportedFiltersAndFormats().

QString QgsVectorFileWriter::filterForDriver ( const QString & driverName ) [static]

Creates a filter for an OGR driver key.

Definition at line 1014 of file qgsvectorfilewriter.cpp.

References driverMetadata().

Referenced by supportedFiltersAndFormats().

QgsVectorFileWriter::WriterError QgsVectorFileWriter::hasError ( )

checks whether there were any errors in constructor

Definition at line 440 of file qgsvectorfilewriter.cpp.

References mError.

Referenced by writeAsVectorFormat().

double QgsVectorFileWriter::mapUnitScaleFactor	(	double	scaleDenominator,
		QgsSymbolV2::OutputUnit	symbolUnits,
		QGis::UnitType	mapUnits
	)		`[private]`

Definition at line 1421 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 1403 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 932 of file qgsvectorfilewriter.cpp.

References driverMetadata(), QgsApplication::registerOgrDrivers(), and TO8.

QgsRenderContext QgsVectorFileWriter::renderContext ( ) const [private]

Definition at line 1437 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 1444 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 1456 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 905 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 1468 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