Base class for raster data providers. More...

#include <qgsrasterdataprovider.h>

Inheritance diagram for QgsRasterDataProvider:

Public Types
enum	ProviderCapability { NoProviderCapabilities = 0, ReadLayerMetadata = 1 << 1, WriteLayerMetadata = 1 << 2 }
	Enumeration with capabilities that raster providers might implement. More...

Public Types inherited from QgsDataProvider
enum	DataCapability { NoDataCapabilities = 0, File = 1, Dir = 1 << 1, Database = 1 << 2, Net = 1 << 3 }

enum	ProviderProperty { EvaluateDefaultValues, CustomData = 3000 }
	Properties are used to pass custom configuration options into data providers. More...

Public Types inherited from QgsRasterInterface
enum	Capability { NoCapabilities = 0, Size = 1 << 1, Create = 1 << 2, Remove = 1 << 3, BuildPyramids = 1 << 4, Identify = 1 << 5, IdentifyValue = 1 << 6, IdentifyText = 1 << 7, IdentifyHtml = 1 << 8, IdentifyFeature = 1 << 9 }
	If you add to this, please also add to capabilitiesString() More...

Signals
void	statusChanged (const QString &) const
	Emit a message to be displayed on status bar, usually used by network providers (WMS,WCS) More...

Signals inherited from QgsDataProvider
void	dataChanged ()
	Emitted whenever a change is made to the data provider which may have caused changes in the provider's data OUTSIDE of QGIS. More...

void	fullExtentCalculated ()
	Emitted whenever a deferred extent calculation is completed by the provider. More...

void	notify (const QString &msg)
	Emitted when the datasource issues a notification. More...

Public Member Functions
	QgsRasterDataProvider ()
	Provider capabilities. More...

	QgsRasterDataProvider (const QString &uri, const QgsDataProvider::ProviderOptions &options=QgsDataProvider::ProviderOptions())
	Constructor for QgsRasterDataProvider. More...

virtual double	bandOffset (int bandNo) const
	Read band offset for raster value. More...

virtual double	bandScale (int bandNo) const
	Read band scale for raster value. More...

QgsRasterBlock *	block (int bandNo, const QgsRectangle &boundingBox, int width, int height, QgsRasterBlockFeedback *feedback=nullptr) override
	Read block of data using given extent and size. More...

virtual QList< QgsRasterPyramid >	buildPyramidList (QList< int > overviewList=QList< int >())
	Returns the raster layers pyramid list. More...

virtual QString	buildPyramids (const QList< QgsRasterPyramid > &pyramidList, const QString &resamplingMethod="NEAREST", QgsRaster::RasterPyramidsFormat format=QgsRaster::PyramidsGTiff, const QStringList &configOptions=QStringList(), QgsRasterBlockFeedback *feedback=nullptr)
	Create pyramid overviews. More...

QgsRasterInterface *	clone () const override=0
	Clone itself, create deep copy. More...

virtual int	colorInterpretation (int bandNo) const
	Returns data type for the band specified by number. More...

virtual QString	colorInterpretationName (int bandNo) const

QString	colorName (int colorInterpretation) const

virtual QList< QgsColorRampShader::ColorRampItem >	colorTable (int bandNo) const

QDateTime	dataTimestamp () const override
	Current time stamp of data source. More...

Qgis::DataType	dataType (int bandNo) const override=0
	Returns data type for the band specified by number. More...

int	dpi () const
	Returns the dpi of the output device. More...

QgsRectangle	extent () const override=0
	Returns the extent of the layer. More...

virtual QImage	getLegendGraphic (double scale=0, bool forceRefresh=false, const QgsRectangle *visibleExtent=nullptr)
	Returns the legend rendered as pixmap. More...

virtual QgsImageFetcher *	getLegendGraphicFetcher (const QgsMapSettings *mapSettings)
	Returns a new image downloader for the raster legend. More...

bool	hasPyramids ()
	Returns true if raster has at least one populated histogram. More...

virtual QString	htmlMetadata ()=0
	Returns metadata in a format suitable for feeding directly into a subset of the GUI raster properties "Metadata" tab. More...

virtual QgsRasterIdentifyResult	identify (const QgsPointXY &point, QgsRaster::IdentifyFormat format, const QgsRectangle &boundingBox=QgsRectangle(), int width=0, int height=0, int dpi=96)
	Identify raster value(s) found on the point position. More...

virtual bool	isEditable () const
	Checks whether the provider is in editing mode, i.e. More...

virtual QString	lastError ()=0
	Returns the verbose error text for the last error in this provider. More...

virtual QString	lastErrorFormat ()
	Returns the format of the error text for the last error in this provider. More...

virtual QString	lastErrorTitle ()=0
	Returns the caption error text for the last error in this provider. More...

virtual QgsRasterDataProvider::ProviderCapabilities	providerCapabilities () const
	Returns flags containing the supported capabilities of the data provider. More...

virtual bool	reload ()
	Reload data (data could change) More...

virtual bool	remove ()
	Remove dataset. More...

virtual double	sample (const QgsPointXY &point, int band, bool *ok=nullptr, const QgsRectangle &boundingBox=QgsRectangle(), int width=0, int height=0, int dpi=96)
	Samples a raster value from the specified band found at the point position. More...

void	setDpi (int dpi)
	Sets the output device resolution. More...

virtual bool	setEditable (bool enabled)
	Turns on/off editing mode of the provider. More...

bool	setInput (QgsRasterInterface *input) override
	Set input. More...

virtual bool	setNoDataValue (int bandNo, double noDataValue)
	Set no data value on created dataset. More...

virtual void	setUserNoDataValue (int bandNo, const QgsRasterRangeList &noData)

virtual void	setUseSourceNoDataValue (int bandNo, bool use)
	Sets the source nodata value usage. More...

Qgis::DataType	sourceDataType (int bandNo) const override=0
	Returns source data type for the band specified by number, source data type may be shorter than dataType. More...

virtual bool	sourceHasNoDataValue (int bandNo) const
	Returns true if source band has no data value. More...

virtual double	sourceNoDataValue (int bandNo) const
	Value representing no data value. More...

virtual int	stepHeight () const
	Step height for raster iterations. More...

virtual int	stepWidth () const
	Step width for raster iterations. More...

QStringList	subLayers () const override
	Returns the sublayers of this layer - useful for providers that manage their own layers, such as WMS. More...

virtual bool	supportsLegendGraphic () const
	Returns whether the provider supplies a legend graphic. More...

QDateTime	timestamp () const override
	Time stamp of data source in the moment when data/metadata were loaded by provider. More...

virtual QgsRasterRangeList	userNoDataValues (int bandNo) const
	Returns a list of user no data value ranges. More...

virtual bool	useSourceNoDataValue (int bandNo) const
	Returns the source nodata value usage. More...

virtual QString	validateCreationOptions (const QStringList &createOptions, const QString &format)
	Validates creation options for a specific dataset and destination format. More...

virtual QString	validatePyramidsConfigOptions (QgsRaster::RasterPyramidsFormat pyramidsFormat, const QStringList &configOptions, const QString &fileFormat)
	Validates pyramid creation options for a specific dataset and destination format. More...

virtual bool	write (void *data, int band, int width, int height, int xOffset, int yOffset)
	Writes into the provider datasource. More...

bool	writeBlock (QgsRasterBlock *block, int band, int xOffset=0, int yOffset=0)
	Writes pixel data from a raster block into the provider data source. More...

Public Member Functions inherited from QgsDataProvider
	QgsDataProvider (const QString &uri=QString(), const QgsDataProvider::ProviderOptions &options=QgsDataProvider::ProviderOptions())
	Create a new dataprovider with the specified in the uri. More...

virtual QgsCoordinateReferenceSystem	crs () const =0
	Returns the coordinate system for the data source. More...

virtual QString	dataSourceUri (bool expandAuthConfig=false) const
	Gets the data source specification. More...

virtual QString	description () const =0
	Returns description. More...

virtual bool	enterUpdateMode ()
	Enter update mode. More...

virtual QgsError	error () const
	Gets current status error. More...

virtual QString	fileRasterFilters () const
	Returns raster file filter string. More...

virtual QString	fileVectorFilters () const
	Returns vector file filter string. More...

virtual void	invalidateConnections (const QString &connection)
	Invalidate connections corresponding to specified name. More...

virtual bool	isValid () const =0
	Returns true if this is a valid layer. More...

virtual QgsLayerMetadata	layerMetadata () const
	Returns layer metadata collected from the provider's source. More...

virtual bool	leaveUpdateMode ()
	Leave update mode. More...

virtual QString	name () const =0
	Returns a provider name. More...

QVariant	providerProperty (ProviderProperty property, const QVariant &defaultValue=QVariant()) const
	Gets the current value of a certain provider property. More...

QVariant	providerProperty (int property, const QVariant &defaultValue) const
	Gets the current value of a certain provider property. More...

virtual void	reloadData ()
	Reloads the data from the source. More...

virtual bool	renderInPreview (const QgsDataProvider::PreviewContext &context)
	Returns whether the layer must be rendered in preview jobs. More...

virtual void	setDataSourceUri (const QString &uri)
	Set the data source specification. More...

virtual void	setLayerOrder (const QStringList &layers)
	Reorder the list of layer names to be rendered by this provider (in order from bottom to top) More...

virtual void	setListening (bool isListening)
	Set whether the provider will listen to datasource notifications If set, the provider will issue notify signals. More...

void	setProviderProperty (ProviderProperty property, const QVariant &value)
	Allows setting arbitrary properties on the provider. More...

void	setProviderProperty (int property, const QVariant &value)
	Allows setting arbitrary properties on the provider. More...

virtual void	setSubLayerVisibility (const QString &name, bool vis)
	Set the visibility of the given sublayer name. More...

virtual bool	setSubsetString (const QString &subset, bool updateFeatureCount=true)
	Set the subset string used to create a subset of features in the layer. More...

void	setUri (const QgsDataSourceUri &uri)
	Set the data source specification. More...

virtual uint	subLayerCount () const
	Returns the number of layers for the current data source. More...

virtual QStringList	subLayerStyles () const
	Sub-layer styles for each sub-layer handled by this provider, in order from bottom to top. More...

virtual QString	subsetString () const
	Returns the subset definition string (typically sql) currently in use by the layer and used by the provider to limit the feature set. More...

virtual bool	supportsSubsetString () const
	Returns true if the provider supports setting of subset strings. More...

virtual void	updateExtents ()
	Update the extents of the layer. More...

QgsDataSourceUri	uri () const
	Gets the data source specification. More...

virtual bool	writeLayerMetadata (const QgsLayerMetadata &metadata)
	Writes layer metadata to the underlying provider source. More...

Public Member Functions inherited from QgsRasterInterface
	QgsRasterInterface (QgsRasterInterface *input=nullptr)

virtual	~QgsRasterInterface ()=default

virtual int	bandCount () const =0
	Gets number of bands. More...

virtual QgsRasterBandStats	bandStatistics (int bandNo, int stats=QgsRasterBandStats::All, const QgsRectangle &extent=QgsRectangle(), int sampleSize=0, QgsRasterBlockFeedback *feedback=nullptr)
	Returns the band statistics. More...

virtual int	capabilities () const
	Returns a bitmask containing the supported capabilities. More...

QString	capabilitiesString () const
	Returns the above in friendly format. More...

virtual void	cumulativeCut (int bandNo, double lowerCount, double upperCount, double &lowerValue, double &upperValue, const QgsRectangle &extent=QgsRectangle(), int sampleSize=0)
	Find values for cumulative pixel count cut. More...

int	dataTypeSize (int bandNo)

virtual QString	generateBandName (int bandNumber) const
	helper function to create zero padded band names More...

virtual bool	hasHistogram (int bandNo, int binCount, double minimum=std::numeric_limits< double >::quiet_NaN(), double maximum=std::numeric_limits< double >::quiet_NaN(), const QgsRectangle &extent=QgsRectangle(), int sampleSize=0, bool includeOutOfRange=false)
	Returns true if histogram is available (cached, already calculated) More...

virtual bool	hasStatistics (int bandNo, int stats=QgsRasterBandStats::All, const QgsRectangle &extent=QgsRectangle(), int sampleSize=0)
	Returns true if histogram is available (cached, already calculated). More...

virtual QgsRasterHistogram	histogram (int bandNo, int binCount=0, double minimum=std::numeric_limits< double >::quiet_NaN(), double maximum=std::numeric_limits< double >::quiet_NaN(), const QgsRectangle &extent=QgsRectangle(), int sampleSize=0, bool includeOutOfRange=false, QgsRasterBlockFeedback *feedback=nullptr)
	Returns a band histogram. More...

virtual QgsRasterInterface *	input () const
	Current input. More...

virtual bool	on () const
	Returns whether the interface is on or off. More...

virtual void	readXml (const QDomElement &filterElem)
	Sets base class members from xml. Usually called from create() methods of subclasses. More...

virtual void	setOn (bool on)
	Sets whether the interface is on or off. More...

virtual const QgsRasterInterface *	sourceInput () const
	Gets source / raw input, the first in pipe, usually provider. More...

virtual QgsRasterInterface *	sourceInput ()
	Gets source / raw input, the first in pipe, usually provider. More...

virtual void	writeXml (QDomDocument &doc, QDomElement &parentElem) const
	Write base class members to xml. More...

virtual int	xBlockSize () const
	Gets block size. More...

virtual int	xSize () const
	Gets raster size. More...

virtual int	yBlockSize () const

virtual int	ySize () const

Static Public Member Functions
static QgsRasterDataProvider *	create (const QString &providerKey, const QString &uri, const QString &format, int nBands, Qgis::DataType type, int width, int height, double *geoTransform, const QgsCoordinateReferenceSystem &crs, const QStringList &createOptions=QStringList())
	Creates a new dataset with mDataSourceURI. More...

static QgsRaster::IdentifyFormat	identifyFormatFromName (const QString &formatName)

static QString	identifyFormatLabel (QgsRaster::IdentifyFormat format)

static QString	identifyFormatName (QgsRaster::IdentifyFormat format)

static Capability	identifyFormatToCapability (QgsRaster::IdentifyFormat format)

static QList< QPair< QString, QString > >	pyramidResamplingMethods (const QString &providerKey)
	Returns a list of pyramid resampling method name and label pairs for given provider. More...

Protected Member Functions
void	copyBaseSettings (const QgsRasterDataProvider &other)
	Copy member variables from other raster data provider. Useful for implementation of clone() method in subclasses. More...

virtual void	readBlock (int bandNo, int xBlock, int yBlock, void *data)
	Read block of data. More...

virtual void	readBlock (int bandNo, QgsRectangle const &viewExtent, int width, int height, void data, QgsRasterBlockFeedback feedback=nullptr)
	Read block of data using give extent and size. More...

bool	userNoDataValuesContains (int bandNo, double value) const
	Returns true if user no data contains value. More...

Protected Member Functions inherited from QgsDataProvider
void	appendError (const QgsErrorMessage &message)
	Add error message. More...

void	setError (const QgsError &error)
	Sets error message. More...

Protected Member Functions inherited from QgsRasterInterface
void	initHistogram (QgsRasterHistogram &histogram, int bandNo, int binCount, double minimum=std::numeric_limits< double >::quiet_NaN(), double maximum=std::numeric_limits< double >::quiet_NaN(), const QgsRectangle &boundingBox=QgsRectangle(), int sampleSize=0, bool includeOutOfRange=false)
	Fill in histogram defaults if not specified. More...

void	initStatistics (QgsRasterBandStats &statistics, int bandNo, int stats=QgsRasterBandStats::All, const QgsRectangle &boundingBox=QgsRectangle(), int binCount=0)
	Fill in statistics defaults if not specified. More...

Protected Attributes
int	mDpi = -1
	Dots per inch. More...

QgsRectangle	mExtent

QList< bool >	mSrcHasNoDataValue
	Source no data value exists. More...

QList< double >	mSrcNoDataValue
	Source no data value is available and is set to be used or internal no data is available. More...

QList< QgsRasterRangeList >	mUserNoDataValue
	List of lists of user defined additional no data values for each band, indexed from 0. More...

QList< bool >	mUseSrcNoDataValue
	Use source nodata value. More...

Protected Attributes inherited from QgsDataProvider
QgsError	mError
	Error. More...

QDateTime	mTimestamp
	Timestamp of data in the moment when the data were loaded by provider. More...

Protected Attributes inherited from QgsRasterInterface
QList< QgsRasterHistogram >	mHistograms
	List of cached histograms, all bands mixed. More...

QgsRasterInterface *	mInput = nullptr

bool	mOn = true

QList< QgsRasterBandStats >	mStatistics
	List of cached statistics, all bands mixed. More...

Additional Inherited Members
Static Public Attributes inherited from QgsDataProvider
static QString	SUBLAYER_SEPARATOR = QString( "!!::!!" )
	String sequence used for separating components of sublayers strings. More...

Detailed Description

Base class for raster data providers.

Definition at line 85 of file qgsrasterdataprovider.h.

Member Enumeration Documentation

◆ ProviderCapability

enum QgsRasterDataProvider::ProviderCapability

Enumeration with capabilities that raster providers might implement.

Since: QGIS 3.0

Enumerator
NoProviderCapabilities	Provider has no capabilities.
ReadLayerMetadata	Provider can read layer metadata from data store. Since QGIS 3.0. See QgsDataProvider::layerMetadata()
WriteLayerMetadata	Provider can write layer metadata to the data store. Since QGIS 3.0. See QgsDataProvider::writeLayerMetadata()

Definition at line 95 of file qgsrasterdataprovider.h.

Constructor & Destructor Documentation

◆ QgsRasterDataProvider() [1/2]

QgsRasterDataProvider::QgsRasterDataProvider ( )

Provider capabilities.

Definition at line 208 of file qgsrasterdataprovider.cpp.

◆ QgsRasterDataProvider() [2/2]

QgsRasterDataProvider::QgsRasterDataProvider	(	const QString &	uri,
		const QgsDataProvider::ProviderOptions &	options = `QgsDataProvider::ProviderOptions()`
	)

Constructor for QgsRasterDataProvider.

The uri argument gives a provider-specific uri indicating the underlying data source and it's parameters.

The options argument specifies generic provider options.

Definition at line 214 of file qgsrasterdataprovider.cpp.

Member Function Documentation

◆ bandOffset()

virtual double QgsRasterDataProvider::bandOffset ( int bandNo ) const

inlinevirtual

Read band offset for raster value.

Since: QGIS 2.3

Definition at line 224 of file qgsrasterdataprovider.h.

◆ bandScale()

virtual double QgsRasterDataProvider::bandScale ( int bandNo ) const

inlinevirtual

Read band scale for raster value.

Since: QGIS 2.3

Definition at line 218 of file qgsrasterdataprovider.h.

◆ block()

QgsRasterBlock * QgsRasterDataProvider::block	(	int	bandNo,
		const QgsRectangle &	boundingBox,
		int	width,
		int	height,
		QgsRasterBlockFeedback *	feedback = `nullptr`
	)

overridevirtual

Read block of data using given extent and size.

Implements QgsRasterInterface.

Definition at line 44 of file qgsrasterdataprovider.cpp.

◆ buildPyramidList()

virtual QList<QgsRasterPyramid> QgsRasterDataProvider::buildPyramidList ( QList< int > overviewList = QList<int>() )

inlinevirtual

Returns the raster layers pyramid list.

Parameters

overviewList used to construct the pyramid list (optional), when empty the list is defined by the provider. A pyramid list defines the POTENTIAL pyramids that can be in a raster. To know which of the pyramid layers ACTUALLY exists you need to look at the existsFlag member in each struct stored in the list.

Definition at line 323 of file qgsrasterdataprovider.h.

◆ buildPyramids()

virtual QString QgsRasterDataProvider::buildPyramids	(	const QList< QgsRasterPyramid > &	pyramidList,
		const QString &	resamplingMethod = `"NEAREST"`,
		QgsRaster::RasterPyramidsFormat	format = `QgsRaster::PyramidsGTiff`,
		const QStringList &	configOptions = `QStringList()`,
		QgsRasterBlockFeedback *	feedback = `nullptr`
	)

inlinevirtual

Create pyramid overviews.

Definition at line 301 of file qgsrasterdataprovider.h.

◆ clone()

QgsRasterInterface* QgsRasterDataProvider::clone ( ) const

overridepure virtual

Clone itself, create deep copy.

Implements QgsRasterInterface.

◆ colorInterpretation()

virtual int QgsRasterDataProvider::colorInterpretation ( int bandNo ) const

inlinevirtual

Returns data type for the band specified by number.

Definition at line 140 of file qgsrasterdataprovider.h.

◆ colorInterpretationName()

virtual QString QgsRasterDataProvider::colorInterpretationName ( int bandNo ) const

inlinevirtual

Definition at line 209 of file qgsrasterdataprovider.h.

◆ colorName()

QString QgsRasterDataProvider::colorName ( int colorInterpretation ) const

inline

Definition at line 146 of file qgsrasterdataprovider.h.

◆ colorTable()

virtual QList<QgsColorRampShader::ColorRampItem> QgsRasterDataProvider::colorTable ( int bandNo ) const

inlinevirtual

Definition at line 248 of file qgsrasterdataprovider.h.

◆ copyBaseSettings()

void QgsRasterDataProvider::copyBaseSettings ( const QgsRasterDataProvider & other )

protected

Copy member variables from other raster data provider. Useful for implementation of clone() method in subclasses.

Definition at line 504 of file qgsrasterdataprovider.cpp.

◆ create()

QgsRasterDataProvider * QgsRasterDataProvider::create	(	const QString &	providerKey,
		const QString &	uri,
		const QString &	format,
		int	nBands,
		Qgis::DataType	type,
		int	width,
		int	height,
		double *	geoTransform,
		const QgsCoordinateReferenceSystem &	crs,
		const QStringList &	createOptions = `QStringList()`
	)

static

Creates a new dataset with mDataSourceURI.

Definition at line 419 of file qgsrasterdataprovider.cpp.

◆ dataTimestamp()

QDateTime QgsRasterDataProvider::dataTimestamp ( ) const

inlineoverridevirtual

Current time stamp of data source.

Reimplemented from QgsDataProvider.

Definition at line 414 of file qgsrasterdataprovider.h.

◆ dataType()

Qgis::DataType QgsRasterDataProvider::dataType ( int bandNo ) const

overridepure virtual

Returns data type for the band specified by number.

Implements QgsRasterInterface.

◆ dpi()

int QgsRasterDataProvider::dpi ( ) const

inline

Returns the dpi of the output device.

Definition at line 405 of file qgsrasterdataprovider.h.

◆ extent()

QgsRectangle QgsRasterDataProvider::extent ( ) const

overridepure virtual

Returns the extent of the layer.

Returns: QgsRectangle containing the extent of the layer

Implements QgsDataProvider.

◆ getLegendGraphic()

virtual QImage QgsRasterDataProvider::getLegendGraphic	(	double	scale = `0`,
		bool	forceRefresh = `false`,
		const QgsRectangle *	visibleExtent = `nullptr`
	)

inlinevirtual

Returns the legend rendered as pixmap.

This is useful for layers which need to get legend layers remotely as WMS.

Parameters

scale	Optional parameter that is the Scale of the layer
forceRefresh	Optional bool parameter to force refresh getLegendGraphic call
visibleExtent	Visible extent for providers supporting contextual legends, in layer CRS

Note: Parameter visibleExtent added in QGIS 2.8; Not available in Python bindings

Definition at line 273 of file qgsrasterdataprovider.h.

◆ getLegendGraphicFetcher()

virtual QgsImageFetcher* QgsRasterDataProvider::getLegendGraphicFetcher ( const QgsMapSettings * mapSettings )

inlinevirtual

Returns a new image downloader for the raster legend.

Parameters

mapSettings map settings for legend providers supporting contextual legends.

Returns: a download handler or null if the provider does not support legend at all. Ownership of the returned object is transferred to caller.

Since: QGIS 2.8

Definition at line 294 of file qgsrasterdataprovider.h.

◆ hasPyramids()

bool QgsRasterDataProvider::hasPyramids ( )

Returns true if raster has at least one populated histogram.

Definition at line 361 of file qgsrasterdataprovider.cpp.

◆ htmlMetadata()

QString QgsRasterDataProvider::htmlMetadata ( )

pure virtual

Returns metadata in a format suitable for feeding directly into a subset of the GUI raster properties "Metadata" tab.

Definition at line 231 of file qgsrasterdataprovider.cpp.

◆ identify()

QgsRasterIdentifyResult QgsRasterDataProvider::identify	(	const QgsPointXY &	point,
		QgsRaster::IdentifyFormat	format,
		const QgsRectangle &	boundingBox = `QgsRectangle()`,
		int	width = `0`,
		int	height = `0`,
		int	dpi = `96`
	)

virtual

Identify raster value(s) found on the point position.

The context parameters extent, width and height are important to identify on the same zoom level as a displayed map and to do effective caching (WCS). If context params are not specified the highest resolution is used. capabilities() may be used to test if format is supported by provider. Values are set to 'no data' or empty string if point is outside data source extent.

Parameters

point	coordinates in data source CRS
format	result format
boundingBox	context bounding box
width	context width
height	context height
dpi	context dpi

Returns: QgsRaster::IdentifyFormatValue: map of values for each band, keys are band numbers (from 1). QgsRaster::IdentifyFormatFeature: map of QgsRasterFeatureList for each sublayer (WMS) - TODO: it is not consistent with QgsRaster::IdentifyFormatValue. QgsRaster::IdentifyFormatHtml: map of HTML strings for each sublayer (WMS). Empty if failed or there are no results (TODO: better error reporting).

Note: The arbitraryness of the returned document is enforced by WMS standards up to at least v1.3.0

See also: sample(), which is much more efficient for simple "value at point" queries.

Definition at line 238 of file qgsrasterdataprovider.cpp.

◆ identifyFormatFromName()

QgsRaster::IdentifyFormat QgsRasterDataProvider::identifyFormatFromName ( const QString & formatName )

static

Definition at line 472 of file qgsrasterdataprovider.cpp.

◆ identifyFormatLabel()

QString QgsRasterDataProvider::identifyFormatLabel ( QgsRaster::IdentifyFormat format )

static

Definition at line 455 of file qgsrasterdataprovider.cpp.

◆ identifyFormatName()

QString QgsRasterDataProvider::identifyFormatName ( QgsRaster::IdentifyFormat format )

static

Definition at line 438 of file qgsrasterdataprovider.cpp.

◆ identifyFormatToCapability()

QgsRasterInterface::Capability QgsRasterDataProvider::identifyFormatToCapability ( QgsRaster::IdentifyFormat format )

static

Definition at line 481 of file qgsrasterdataprovider.cpp.

◆ isEditable()

virtual bool QgsRasterDataProvider::isEditable ( ) const

inlinevirtual

Checks whether the provider is in editing mode, i.e.

raster write operations will be accepted. By default providers are not editable. Use setEditable() method to enable/disable editing.

See also: setEditable(), writeBlock()

Since: QGIS 3.0

Definition at line 422 of file qgsrasterdataprovider.h.

◆ lastError()

virtual QString QgsRasterDataProvider::lastError ( )

pure virtual

Returns the verbose error text for the last error in this provider.

If an operation returns 0 (e.g. draw()), this function returns the text of the error associated with the failure. Interactive users of this provider can then, for example, call a QMessageBox to display the contents.

◆ lastErrorFormat()

QString QgsRasterDataProvider::lastErrorFormat ( )

virtual

Returns the format of the error text for the last error in this provider.

Definition at line 321 of file qgsrasterdataprovider.cpp.

◆ lastErrorTitle()

virtual QString QgsRasterDataProvider::lastErrorTitle ( )

pure virtual

Returns the caption error text for the last error in this provider.

If an operation returns 0 (e.g. draw()), this function returns the text of the error associated with the failure. Interactive users of this provider can then, for example, call a QMessageBox to display the contents.

◆ providerCapabilities()

QgsRasterDataProvider::ProviderCapabilities QgsRasterDataProvider::providerCapabilities ( ) const

virtual

Returns flags containing the supported capabilities of the data provider.

Since: QGIS 3.0

Definition at line 220 of file qgsrasterdataprovider.cpp.

◆ pyramidResamplingMethods()

QList< QPair< QString, QString > > QgsRasterDataProvider::pyramidResamplingMethods ( const QString & providerKey )

static

Returns a list of pyramid resampling method name and label pairs for given provider.

Definition at line 339 of file qgsrasterdataprovider.cpp.

◆ readBlock() [1/2]

virtual void QgsRasterDataProvider::readBlock	(	int	bandNo,
		int	xBlock,
		int	yBlock,
		void *	data
	)

inlineprotectedvirtual

Read block of data.

Note: not available in Python bindings

Definition at line 541 of file qgsrasterdataprovider.h.

◆ readBlock() [2/2]

virtual void QgsRasterDataProvider::readBlock	(	int	bandNo,
		QgsRectangle const &	viewExtent,
		int	width,
		int	height,
		void *	data,
		QgsRasterBlockFeedback *	feedback = `nullptr`
	)

inlineprotectedvirtual

Read block of data using give extent and size.

Note: not available in Python bindings

Definition at line 548 of file qgsrasterdataprovider.h.

◆ reload()

virtual bool QgsRasterDataProvider::reload ( )

inlinevirtual

Reload data (data could change)

Definition at line 207 of file qgsrasterdataprovider.h.

◆ remove()

virtual bool QgsRasterDataProvider::remove ( )

inlinevirtual

Remove dataset.

Definition at line 484 of file qgsrasterdataprovider.h.

◆ sample()

double QgsRasterDataProvider::sample	(	const QgsPointXY &	point,
		int	band,
		bool *	ok = `nullptr`,
		const QgsRectangle &	boundingBox = `QgsRectangle()`,
		int	width = `0`,
		int	height = `0`,
		int	dpi = `96`
	)

virtual

Samples a raster value from the specified band found at the point position.

The context parameters boundingBox, width and height are important to identify on the same zoom level as a displayed map and to do effective caching (WCS). If context params are not specified the highest resolution is used.

If ok is specified and the point is outside data source extent, or an invalid band number was specified, then ok will be set to false. In this case the function will return a NaN value.

See also: identify(), which is much more flexible but considerably less efficient.

Since: QGIS 3.4

Definition at line 303 of file qgsrasterdataprovider.cpp.

◆ setDpi()

void QgsRasterDataProvider::setDpi ( int dpi )

inline

Sets the output device resolution.

Definition at line 408 of file qgsrasterdataprovider.h.

◆ setEditable()

virtual bool QgsRasterDataProvider::setEditable ( bool enabled )

inlinevirtual

Turns on/off editing mode of the provider.

When in editing mode, it is possible to overwrite data of the provider using writeBlock() calls.

Returns: true if the switch to/from editing mode was successful

Note: Only some providers support editing mode and even those may fail to turn the underlying data source into editing mode, so it is necessary to check the return value whether the operation was successful.

See also: isEditable(), writeBlock()

Since: QGIS 3.0

Definition at line 434 of file qgsrasterdataprovider.h.

◆ setInput()

bool QgsRasterDataProvider::setInput ( QgsRasterInterface * input )

inlineoverridevirtual

Set input.

Returns true if set correctly, false if cannot use that input

Reimplemented from QgsRasterInterface.

Definition at line 126 of file qgsrasterdataprovider.h.

◆ setNoDataValue()

virtual bool QgsRasterDataProvider::setNoDataValue	(	int	bandNo,
		double	noDataValue
	)

inlinevirtual

Set no data value on created dataset.

Parameters

bandNo	band number
noDataValue	no data value

Definition at line 481 of file qgsrasterdataprovider.h.

◆ setUserNoDataValue()

void QgsRasterDataProvider::setUserNoDataValue	(	int	bandNo,
		const QgsRasterRangeList &	noData
	)

virtual

Definition at line 381 of file qgsrasterdataprovider.cpp.

◆ setUseSourceNoDataValue()

void QgsRasterDataProvider::setUseSourceNoDataValue	(	int	bandNo,
		bool	use
	)

virtual

Sets the source nodata value usage.

Definition at line 32 of file qgsrasterdataprovider.cpp.

◆ sourceDataType()

Qgis::DataType QgsRasterDataProvider::sourceDataType ( int bandNo ) const

overridepure virtual

Returns source data type for the band specified by number, source data type may be shorter than dataType.

Reimplemented from QgsRasterInterface.

◆ sourceHasNoDataValue()

virtual bool QgsRasterDataProvider::sourceHasNoDataValue ( int bandNo ) const

inlinevirtual

Returns true if source band has no data value.

Definition at line 232 of file qgsrasterdataprovider.h.

◆ sourceNoDataValue()

virtual double QgsRasterDataProvider::sourceNoDataValue ( int bandNo ) const

inlinevirtual

Value representing no data value.

Definition at line 241 of file qgsrasterdataprovider.h.

◆ statusChanged

void QgsRasterDataProvider::statusChanged ( const QString & ) const

signal

Emit a message to be displayed on status bar, usually used by network providers (WMS,WCS)

Since: QGIS 2.14

◆ stepHeight()

virtual int QgsRasterDataProvider::stepHeight ( ) const

inlinevirtual

Step height for raster iterations.

See also: stepWidth()

Since: QGIS 3.0

Definition at line 525 of file qgsrasterdataprovider.h.

◆ stepWidth()

virtual int QgsRasterDataProvider::stepWidth ( ) const

inlinevirtual

Step width for raster iterations.

See also: stepHeight()

Since: QGIS 3.0

Definition at line 518 of file qgsrasterdataprovider.h.

◆ subLayers()

QStringList QgsRasterDataProvider::subLayers ( ) const

inlineoverridevirtual

Returns the sublayers of this layer - useful for providers that manage their own layers, such as WMS.

Reimplemented from QgsDataProvider.

Definition at line 254 of file qgsrasterdataprovider.h.

◆ supportsLegendGraphic()

virtual bool QgsRasterDataProvider::supportsLegendGraphic ( ) const

inlinevirtual

Returns whether the provider supplies a legend graphic.

Definition at line 260 of file qgsrasterdataprovider.h.

◆ timestamp()

QDateTime QgsRasterDataProvider::timestamp ( ) const

inlineoverridevirtual

Time stamp of data source in the moment when data/metadata were loaded by provider.

Reimplemented from QgsDataProvider.

Definition at line 411 of file qgsrasterdataprovider.h.

◆ userNoDataValues()

virtual QgsRasterRangeList QgsRasterDataProvider::userNoDataValues ( int bandNo ) const

inlinevirtual

Returns a list of user no data value ranges.

Definition at line 246 of file qgsrasterdataprovider.h.

◆ userNoDataValuesContains()

bool QgsRasterDataProvider::userNoDataValuesContains	(	int	bandNo,
		double	value
	)		const

protected

Returns true if user no data contains value.

Definition at line 498 of file qgsrasterdataprovider.cpp.

◆ useSourceNoDataValue()

virtual bool QgsRasterDataProvider::useSourceNoDataValue ( int bandNo ) const

inlinevirtual

Returns the source nodata value usage.

Definition at line 235 of file qgsrasterdataprovider.h.

◆ validateCreationOptions()

virtual QString QgsRasterDataProvider::validateCreationOptions	(	const QStringList &	createOptions,
		const QString &	format
	)

inlinevirtual

Validates creation options for a specific dataset and destination format.

Note: used by GDAL provider only; see also validateCreationOptionsFormat() in gdal provider for validating options based on format only

Definition at line 497 of file qgsrasterdataprovider.h.

◆ validatePyramidsConfigOptions()

virtual QString QgsRasterDataProvider::validatePyramidsConfigOptions	(	QgsRaster::RasterPyramidsFormat	pyramidsFormat,
		const QStringList &	configOptions,
		const QString &	fileFormat
	)

inlinevirtual

Validates pyramid creation options for a specific dataset and destination format.

Note: used by GDAL provider only

Definition at line 504 of file qgsrasterdataprovider.h.

◆ write()

virtual bool QgsRasterDataProvider::write	(	void *	data,
		int	band,
		int	width,
		int	height,
		int	xOffset,
		int	yOffset
	)

inlinevirtual

Writes into the provider datasource.

Definition at line 438 of file qgsrasterdataprovider.h.

◆ writeBlock()

bool QgsRasterDataProvider::writeBlock	(	QgsRasterBlock *	block,
		int	band,
		int	xOffset = `0`,
		int	yOffset = `0`
	)

Writes pixel data from a raster block into the provider data source.

This will override previously stored pixel values. It is assumed that cells in the passed raster block are aligned with the cells of the data source. If raster block does not cover the whole area of the data source, only a subset of pixels covered by the raster block will be overwritten. By default, writing of raster data starts from the first cell of the raster - it is possible to set offset in pixels by specifying non-zero xOffset and yOffset values.

Writing is supported only by some data providers. Provider has to be in editing mode in order to allow write operations.

See also: isEditable(), setEditable()

Returns: true on success

Since: QGIS 3.0

Definition at line 326 of file qgsrasterdataprovider.cpp.

Member Data Documentation

◆ mDpi

int QgsRasterDataProvider::mDpi = -1

protected

Dots per inch.

Extended WMS (e.g. QGIS mapserver) support DPI dependent output and therefore are suited for printing. A value of -1 means it has not been set

Definition at line 560 of file qgsrasterdataprovider.h.

◆ mExtent

QgsRectangle QgsRasterDataProvider::mExtent

mutableprotected

Definition at line 584 of file qgsrasterdataprovider.h.

◆ mSrcHasNoDataValue

QList<bool> QgsRasterDataProvider::mSrcHasNoDataValue

protected

Source no data value exists.

Definition at line 571 of file qgsrasterdataprovider.h.

◆ mSrcNoDataValue

QList<double> QgsRasterDataProvider::mSrcNoDataValue

protected

Source no data value is available and is set to be used or internal no data is available.

Used internally only Cell value representing original source no data. e.g. -9999, indexed from 0

Definition at line 568 of file qgsrasterdataprovider.h.

◆ mUserNoDataValue

QList< QgsRasterRangeList > QgsRasterDataProvider::mUserNoDataValue

protected

List of lists of user defined additional no data values for each band, indexed from 0.

Definition at line 582 of file qgsrasterdataprovider.h.

◆ mUseSrcNoDataValue

QList<bool> QgsRasterDataProvider::mUseSrcNoDataValue

protected

Use source nodata value.

User can disable usage of source nodata value as nodata. It may happen that a value is wrongly given by GDAL as nodata (e.g. 0) and it has to be treated as regular value.

Definition at line 577 of file qgsrasterdataprovider.h.

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

/tmp/buildd/qgis-3.6.0+99unstable/src/core/raster/qgsrasterdataprovider.h
/tmp/buildd/qgis-3.6.0+99unstable/src/core/raster/qgsrasterdataprovider.cpp

Public Types

Signals

Public Member Functions

Static Public Member Functions

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ ProviderCapability

Constructor & Destructor Documentation

◆ QgsRasterDataProvider() [1/2]

◆ QgsRasterDataProvider() [2/2]

Member Function Documentation

◆ bandOffset()

◆ bandScale()

◆ block()

◆ buildPyramidList()

◆ buildPyramids()

◆ clone()

◆ colorInterpretation()

◆ colorInterpretationName()

◆ colorName()

◆ colorTable()

◆ copyBaseSettings()

◆ create()

◆ dataTimestamp()

◆ dataType()

◆ dpi()

◆ extent()

◆ getLegendGraphic()

◆ getLegendGraphicFetcher()

◆ hasPyramids()

◆ htmlMetadata()

◆ identify()

◆ identifyFormatFromName()

◆ identifyFormatLabel()

◆ identifyFormatName()

◆ identifyFormatToCapability()

◆ isEditable()

◆ lastError()

◆ lastErrorFormat()

◆ lastErrorTitle()

◆ providerCapabilities()

◆ pyramidResamplingMethods()

◆ readBlock() [1/2]

◆ readBlock() [2/2]

◆ reload()

◆ remove()

◆ sample()

◆ setDpi()

◆ setEditable()

◆ setInput()

◆ setNoDataValue()

◆ setUserNoDataValue()

◆ setUseSourceNoDataValue()

◆ sourceDataType()

◆ sourceHasNoDataValue()

◆ sourceNoDataValue()

◆ statusChanged

◆ stepHeight()

◆ stepWidth()

◆ subLayers()

◆ supportsLegendGraphic()

◆ timestamp()

◆ userNoDataValues()

◆ userNoDataValuesContains()

◆ useSourceNoDataValue()

◆ validateCreationOptions()

◆ validatePyramidsConfigOptions()

◆ write()

◆ writeBlock()

Member Data Documentation

◆ mDpi

◆ mExtent

◆ mSrcHasNoDataValue

◆ mSrcNoDataValue

◆ mUserNoDataValue

◆ mUseSrcNoDataValue