This class provides qgis with the ability to render raster datasets onto the mapcanvas. More...

#include <qgsrasterlayer.h>

Inheritance diagram for QgsRasterLayer:

Public Types
enum	ColorShadingAlgorithm { UndefinedShader, PseudoColorShader, FreakOutShader, ColorRampShader, UserDefinedShader }
	This enumerator describes the types of shading that can be used. More...

enum	LayerType { GrayOrUndefined, Palette, Multiband, ColorLayer }
	This enumerator describes the type of raster layer. More...

Public Types inherited from QgsMapLayer
enum	LayerType { VectorLayer, RasterLayer, PluginLayer }
	Layers enum defining the types of layers that can be added to a map. More...

Public Slots
void	onProgress (int, double, const QString &)
	receive progress signal from provider More...

void	showStatusMessage (const QString &theMessage)

Q_DECL_DEPRECATED void	updateProgress (int, int)

Public Slots inherited from QgsMapLayer
Q_DECL_DEPRECATED void	clearCacheImage ()
	Clear cached image. More...

void	emitStyleChanged ()
	Triggers an emission of the styleChanged() signal. More...

virtual void	invalidTransformInput ()
	Event handler for when a coordinate transform fails due to bad vertex error. More...

void	setMaximumScale (double theMaxScale)
	Sets the maximum scale denominator at which the layer will be visible. More...

void	setMinimumScale (double theMinScale)
	Sets the minimum scale denominator at which the layer will be visible. More...

void	setScaleBasedVisibility (const bool enabled)
	Sets whether scale based visibility is enabled for the layer. More...

Q_DECL_DEPRECATED void	toggleScaleBasedVisibility (bool theVisibilityFlag)
	Accessor for the scale based visilibility flag. More...

void	triggerRepaint ()
	Will advice the map canvas (and any other interested party) that this layer requires to be repainted. More...

Signals
void	progressUpdate (int theValue)
	Signal for notifying listeners of long running processes. More...

Signals inherited from QgsMapLayer
void	blendModeChanged (QPainter::CompositionMode blendMode)
	Signal emitted when the blend mode is changed, through QgsMapLayer::setBlendMode() More...

void	configChanged ()
	Emitted whenever the configuration is changed. More...

void	dataChanged ()
	Data of layer changed. More...

Q_DECL_DEPRECATED void	drawingProgress (int theProgress, int theTotalSteps)

void	layerCrsChanged ()
	Emit a signal that layer's CRS has been reset. More...

Q_DECL_DEPRECATED void	layerNameChanged ()
	Emit a signal that the layer name has been changed. More...

void	legendChanged ()
	Signal emitted when legend of the layer has changed. More...

void	nameChanged ()
	Emitted when the name has been changed. More...

void	recalculateExtents ()
	This is used to send a request that any mapcanvas using this layer update its extents. More...

void	rendererChanged ()
	Signal emitted when renderer is changed. More...

void	repaintRequested ()
	By emitting this signal the layer tells that either appearance or content have been changed and any view showing the rendered layer should refresh itself. More...

void	screenUpdateRequested ()

void	statusChanged (const QString &theStatus)
	Emit a signal with status (e.g. More...

void	styleChanged ()
	Signal emitted whenever a change affects the layer's style. More...

Public Member Functions
	QgsRasterLayer ()
	Constructor. More...

	QgsRasterLayer (const QString &path, const QString &baseName=QString::null, bool loadDefaultStyleFlag=true)
	This is the constructor for the RasterLayer class. More...

	QgsRasterLayer (const QString &uri, const QString &baseName, const QString &providerKey, bool loadDefaultStyleFlag=true)
	[ data provider interface ] Constructor in provider mode More...

	~QgsRasterLayer ()
	The destructor. More...

int	bandCount () const
	Get the number of bands in this layer. More...

const QString	bandName (int theBandNoInt)
	Get the name of a band given its number. More...

QgsBrightnessContrastFilter *	brightnessFilter () const

virtual QgsMapLayerRenderer *	createMapRenderer (QgsRenderContext &rendererContext) override
	Return new instance of QgsMapLayerRenderer that will be used for rendering of given context. More...

QgsRasterDataProvider *	dataProvider ()
	Returns the data provider. More...

const QgsRasterDataProvider *	dataProvider () const
	Returns the data provider in a const-correct manner. More...

bool	draw (QgsRenderContext &rendererContext) override
	This is called when the view on the raster layer needs to be redrawn. More...

void	draw (QPainter theQPainter, QgsRasterViewPort myRasterViewPort, const QgsMapToPixel *theQgsMapToPixel=nullptr)
	This is an overloaded version of the draw() function that is called by both draw() and thumbnailAsPixmap. More...

int	height () const
	Accessor that returns the height of the (unclipped) raster. More...

QgsHueSaturationFilter *	hueSaturationFilter () const

virtual bool	isSpatial () const override
	Returns true if the layer is considered a spatial layer, ie it has some form of geometry associated with it. More...

QgsLegendColorList	legendSymbologyItems () const
	Returns a list with classification items (Text and color) More...

QString	metadata () override
	Obtain GDAL Metadata for this layer. More...

QPixmap	paletteAsPixmap (int theBandNumber=1)
	Get an 100x100 pixmap of the color palette. More...

QgsRasterPipe *	pipe ()
	Get raster pipe. More...

QImage	previewAsImage (QSize size, const QColor &bgColor=Qt::white, QImage::Format format=QImage::Format_ARGB32_Premultiplied)
	Draws a preview of the rasterlayer into a QImage. More...

Q_DECL_DEPRECATED QPixmap	previewAsPixmap (QSize size, const QColor &bgColor=Qt::white)
	Draws a preview of the rasterlayer into a pixmap. More...

QString	providerType () const
	[ data provider interface ] Which provider is being used for this Raster Layer? More...

LayerType	rasterType ()
	Accessor for raster layer type (which is a read only property) More...

double	rasterUnitsPerPixelX ()
	Returns the number of raster units per each raster pixel. More...

double	rasterUnitsPerPixelY ()

virtual void	reload () override
	Synchronises with changes in the datasource. More...

QgsRasterRenderer *	renderer () const

QgsRasterResampleFilter *	resampleFilter () const
	Set raster resample filter. More...

void	setContrastEnhancement (QgsContrastEnhancement::ContrastEnhancementAlgorithm theAlgorithm, QgsRaster::ContrastEnhancementLimits theLimits=QgsRaster::ContrastEnhancementMinMax, const QgsRectangle &theExtent=QgsRectangle(), int theSampleSize=SAMPLE_SIZE, bool theGenerateLookupTableFlag=true)
	Set contrast enhancement algorithm. More...

void	setDataProvider (const QString &provider)
	[ data provider interface ] Set the data provider More...

void	setDefaultContrastEnhancement ()
	Set default contrast enhancement. More...

Q_DECL_DEPRECATED void	setDrawingStyle (const QString &theDrawingStyleQString)
	Overloaded version of the above function for convenience when restoring from xml. More...

virtual void	setLayerOrder (const QStringList &layers) override
	Reorders the previously selected sublayers of this layer from bottom to top. More...

void	setRenderer (QgsRasterRenderer *theRenderer)
	Set raster renderer. More...

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

void	showProgress (int theValue)
	[ data provider interface ] A wrapper function to emit a progress update signal More...

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

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

int	width () const
	Accessor that returns the width of the (unclipped) raster. More...

Public Member Functions inherited from QgsMapLayer
	QgsMapLayer (QgsMapLayer::LayerType type=VectorLayer, const QString &lyrname=QString::null, const QString &source=QString::null)
	Constructor. More...

virtual	~QgsMapLayer ()
	Destructor. More...

QString	abstract () const
	Get the abstract of the layer used by QGIS Server in GetCapabilities request. More...

QString	attribution () const
	Get the attribution of the layer used by QGIS Server in GetCapabilities request Attribution indicates the provider of a Layer or collection of Layers. More...

QString	attributionUrl () const
	Get the attribution URL of the layer used by QGIS Server in GetCapabilities request Attribution indicates the provider of a Layer or collection of Layers. More...

QPainter::CompositionMode	blendMode () const
	Returns the current blending mode for a layer. More...

Q_DECL_DEPRECATED QImage *	cacheImage ()

const QgsCoordinateReferenceSystem &	crs () const
	Returns layer's spatial reference system. More...

QVariant	customProperty (const QString &value, const QVariant &defaultValue=QVariant()) const
	Read a custom property from layer. More...

QString	dataUrl () const
	Get the DataUrl of the layer used by QGIS Server in GetCapabilities request DataUrl is a a link to the underlying data represented by a particular layer. More...

QString	dataUrlFormat () const
	Get the DataUrl format of the layer used by QGIS Server in GetCapabilities request DataUrl is a a link to the underlying data represented by a particular layer. More...

virtual void	drawLabels (QgsRenderContext &rendererContext)
	Draw labels. More...

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

virtual void	exportNamedStyle (QDomDocument &doc, QString &errorMsg)
	Export the properties of this layer as named style in a QDomDocument. More...

virtual void	exportSldStyle (QDomDocument &doc, QString &errorMsg)
	Export the properties of this layer as SLD style in a QDomDocument. More...

virtual QgsRectangle	extent ()
	Return the extent of the layer. More...

bool	hasScaleBasedVisibility () const
	Returns whether scale based visibility is enabled for the layer. More...

QString	id () const
	Get this layer's unique ID, this ID is used to access this layer from map layer registry. More...

virtual bool	importNamedStyle (QDomDocument &doc, QString &errorMsg)
	Import the properties of this layer from a QDomDocument. More...

virtual bool	isEditable () const
	True if the layer can be edited. More...

bool	isInScaleRange (double scale) const
	Tests whether the layer should be visible at the specified scale. More...

bool	isValid ()
	Return the status of the layer. More...

QString	keywordList () const
	Get the keyword list of the layer used by QGIS Server in GetCapabilities request. More...

virtual Q_DECL_DEPRECATED QString	lastError ()

virtual Q_DECL_DEPRECATED QString	lastErrorTitle ()

QgsMapLayerLegend *	legend () const
	Can be null. More...

QString	legendUrl () const

QString	legendUrlFormat () const

virtual QString	loadDefaultStyle (bool &theResultFlag)
	Retrieve the default style for this layer if one exists (either as a .qml file on disk or as a record in the users style table in their personal qgis.db) More...

virtual QString	loadNamedStyle (const QString &theURI, bool &theResultFlag)
	Retrieve a named style for this layer if one exists (either as a .qml file on disk or as a record in the users style table in their personal qgis.db) More...

virtual bool	loadNamedStyleFromDb (const QString &db, const QString &theURI, QString &qml)

virtual QString	loadSldStyle (const QString &theURI, bool &theResultFlag)

double	maximumScale () const
	Returns the maximum scale denominator at which the layer is visible. More...

QString	metadataUrl () const
	Get the metadata URL of the layer used by QGIS Server in GetCapabilities request MetadataUrl is a a link to the detailed, standardized metadata about the data. More...

QString	metadataUrlFormat () const
	Get the metadata format of the layer used by QGIS Server in GetCapabilities request MetadataUrlType indicates how the metadata is structured. More...

QString	metadataUrlType () const
	Get the metadata type of the layer used by QGIS Server in GetCapabilities request MetadataUrlType indicates the standard to which the metadata complies. More...

double	minimumScale () const
	Returns the minimum scale denominator at which the layer is visible. More...

QString	name () const
	Get the display name of the layer. More...

virtual Q_DECL_DEPRECATED void	onCacheImageDelete ()

QString	originalName () const
	Get the original name of the layer. More...

QString	publicSource () const
	Gets a version of the internal layer definition that has sensitive bits removed (for example, the password). More...

bool	readLayerXML (const QDomElement &layerElement, const QString &relativeBasePath=QString())
	Sets state from Dom document. More...

bool	readOnly () const
	Returns if this layer is read only. More...

virtual bool	readSld (const QDomNode &node, QString &errorMessage)

void	removeCustomProperty (const QString &key)
	Remove a custom property from layer. More...

virtual QString	saveDefaultStyle (bool &theResultFlag)
	Save the properties of this layer as the default style (either as a .qml file on disk or as a record in the users style table in their personal qgis.db) More...

virtual QString	saveNamedStyle (const QString &theURI, bool &theResultFlag)
	Save the properties of this layer as a named style (either as a .qml file on disk or as a record in the users style table in their personal qgis.db) More...

virtual QString	saveSldStyle (const QString &theURI, bool &theResultFlag)

void	setAbstract (const QString &abstract)
	Set the abstract of the layer used by QGIS Server in GetCapabilities request. More...

void	setAttribution (const QString &attrib)
	Set the attribution of the layer used by QGIS Server in GetCapabilities request Attribution indicates the provider of a Layer or collection of Layers. More...

void	setAttributionUrl (const QString &attribUrl)
	Set the attribution URL of the layer used by QGIS Server in GetCapabilities request Attribution indicates the provider of a Layer or collection of Layers. More...

void	setBlendMode (QPainter::CompositionMode blendMode)
	Set the blending mode used for rendering a layer. More...

Q_DECL_DEPRECATED void	setCacheImage (QImage *)

void	setCrs (const QgsCoordinateReferenceSystem &srs, bool emitSignal=true)
	Sets layer's spatial reference system. More...

void	setCustomProperty (const QString &key, const QVariant &value)
	Set a custom property for layer. More...

void	setDataUrl (const QString &dataUrl)
	Set the DataUrl of the layer used by QGIS Server in GetCapabilities request DataUrl is a a link to the underlying data represented by a particular layer. More...

void	setDataUrlFormat (const QString &dataUrlFormat)
	Set the DataUrl format of the layer used by QGIS Server in GetCapabilities request DataUrl is a a link to the underlying data represented by a particular layer. More...

void	setKeywordList (const QString &keywords)
	Set the keyword list of the layer used by QGIS Server in GetCapabilities request. More...

Q_DECL_DEPRECATED void	setLayerName (const QString &name)
	Set the display name of the layer. More...

void	setLegend (QgsMapLayerLegend *legend)
	Assign a legend controller to the map layer. More...

void	setLegendUrl (const QString &legendUrl)

void	setLegendUrlFormat (const QString &legendUrlFormat)

void	setMetadataUrl (const QString &metaUrl)
	Set the metadata URL of the layer used by QGIS Server in GetCapabilities request MetadataUrl is a a link to the detailed, standardized metadata about the data. More...

void	setMetadataUrlFormat (const QString &metaUrlFormat)
	Set the metadata format of the layer used by QGIS Server in GetCapabilities request MetadataUrlType indicates how the metadata is structured. More...

void	setMetadataUrlType (const QString &metaUrlType)
	Set the metadata type of the layer used by QGIS Server in GetCapabilities request MetadataUrlType indicates the standard to which the metadata complies. More...

void	setName (const QString &name)
	Set the display name of the layer. More...

void	setShortName (const QString &shortName)
	Set the short name of the layer used by QGIS Server to identify the layer. More...

void	setTitle (const QString &title)
	Set the title of the layer used by QGIS Server in GetCapabilities request. More...

QString	shortName () const
	Get the short name of the layer used by QGIS Server to identify the layer. More...

QString	source () const
	Returns the source for the layer. More...

QgsMapLayerStyleManager *	styleManager () const
	Get access to the layer's style manager. More...

virtual QString	styleURI ()
	Retrieve the style URI for this layer (either as a .qml file on disk or as a record in the users style table in their personal qgis.db) More...

QString	title () const
	Get the title of the layer used by QGIS Server in GetCapabilities request. More...

QgsMapLayer::LayerType	type () const
	Get the type of the layer. More...

QUndoStack *	undoStack ()
	Return pointer to layer's undo stack. More...

QUndoStack *	undoStackStyles ()
	Return pointer to layer's style undo stack. More...

bool	writeLayerXML (QDomElement &layerElement, QDomDocument &document, const QString &relativeBasePath=QString())
	Stores state in Dom node. More...

Public Member Functions inherited from QObject
	QObject (QObject *parent)

	QObject (QObject parent, const char name)

virtual	~QObject ()

bool	blockSignals (bool block)

QObject *	child (const char objName, const char inheritsClass, bool recursiveSearch) const

const QObjectList &	children () const

const char *	className () const

bool	connect (const QObject sender, const char signal, const char *method, Qt::ConnectionType type) const

void	deleteLater ()

void	destroyed (QObject *obj)

bool	disconnect (const QObject receiver, const char method)

bool	disconnect (const char signal, const QObject receiver, const char *method)

void	dumpObjectInfo ()

void	dumpObjectTree ()

QList< QByteArray >	dynamicPropertyNames () const

virtual bool	event (QEvent *e)

virtual bool	eventFilter (QObject watched, QEvent event)

T	findChild (const QString &name) const

QList< T >	findChildren (const QRegExp &regExp) const

QList< T >	findChildren (const QString &name) const

bool	inherits (const char *className) const

void	insertChild (QObject *object)

void	installEventFilter (QObject *filterObj)

bool	isA (const char *className) const

bool	isWidgetType () const

void	killTimer (int id)

virtual const QMetaObject *	metaObject () const

void	moveToThread (QThread *targetThread)

const char *	name () const

const char *	name (const char *defaultName) const

QString	objectName () const

QObject *	parent () const

QVariant	property (const char *name) const

void	removeChild (QObject *object)

void	removeEventFilter (QObject *obj)

void	setName (const char *name)

void	setObjectName (const QString &name)

void	setParent (QObject *parent)

bool	setProperty (const char *name, const QVariant &value)

bool	signalsBlocked () const

int	startTimer (int interval)

QThread *	thread () const

Static Public Member Functions
static bool	isValidRasterFileName (const QString &theFileNameQString, QString &retError)
	This helper checks to see whether the file name appears to be a valid raster file name. More...

static bool	isValidRasterFileName (const QString &theFileNameQString)

static QDateTime	lastModified (const QString &name)
	Return time stamp for given file name. More...

Static Public Member Functions inherited from QgsMapLayer
static QDomDocument	asLayerDefinition (const QList< QgsMapLayer *> &layers, const QString &relativeBasePath=QString())
	Returns the given layer as a layer definition document Layer definitions store the data source as well as styling and custom properties. More...

static QString	capitaliseLayerName (const QString &name)
	A convenience function to (un)capitalise the layer name. More...

static QList< QgsMapLayer * >	fromLayerDefinition (QDomDocument &document, bool addToRegistry=false, bool addToLegend=false, const QString &relativeBasePath=QString())
	Creates a new layer from a layer defininition document. More...

static QList< QgsMapLayer * >	fromLayerDefinitionFile (const QString &qlrfile)

Static Public Member Functions inherited from QObject
bool	connect (const QObject sender, const char signal, const QObject receiver, const char method, Qt::ConnectionType type)

bool	connect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method, Qt::ConnectionType type)

bool	disconnect (const QObject sender, const char signal, const QObject receiver, const char method)

bool	disconnect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method)

QString	tr (const char sourceText, const char disambiguation, int n)

QString	trUtf8 (const char sourceText, const char disambiguation, int n)

Static Public Attributes
static const double	CUMULATIVE_CUT_LOWER = 0.02
	Default cumulative cut lower limit. More...

static const double	CUMULATIVE_CUT_UPPER = 0.98
	Default cumulative cut upper limit. More...

static const double	SAMPLE_SIZE = 250000
	Default sample size (number of pixels) for estimated statistics/histogram calculation. More...

Protected Member Functions
bool	readStyle (const QDomNode &node, QString &errorMessage) override
	Read the style information for the current layer from the Dom node supplied. More...

bool	readSymbology (const QDomNode &node, QString &errorMessage) override
	Read the symbology for the current layer from the Dom node supplied. More...

bool	readXml (const QDomNode &layer_node) override
	Reads layer specific state from project file Dom node. More...

bool	writeStyle (QDomNode &node, QDomDocument &doc, QString &errorMessage) const override
	Write the style for the layer into the docment provided. More...

bool	writeSymbology (QDomNode &, QDomDocument &doc, QString &errorMessage) const override
	Write the symbology for the layer into the docment provided. More...

bool	writeXml (QDomNode &layer_node, QDomDocument &doc) override
	Write layer specific state to project file Dom node. More...

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

void	readCustomProperties (const QDomNode &layerNode, const QString &keyStartsWith="")
	Read custom properties from project file. More...

void	readStyleManager (const QDomNode &layerNode)
	Read style manager's configuration (if any). More...

void	setError (const QgsError &theError)
	Set error message. More...

virtual void	setExtent (const QgsRectangle &rect)
	Set the extent. More...

void	setValid (bool valid)
	Set whether layer is valid or not - should be used in constructor. More...

void	writeCustomProperties (QDomNode &layerNode, QDomDocument &doc) const
	Write custom properties to project file. More...

void	writeStyleManager (QDomNode &layerNode, QDomDocument &doc) const
	Write style manager's configuration (if exists). More...

Protected Member Functions inherited from QObject
bool	checkConnectArgs (const char signal, const QObject object, const char *method)

virtual void	childEvent (QChildEvent *event)

virtual void	connectNotify (const char *signal)

virtual void	customEvent (QEvent *event)

virtual void	disconnectNotify (const char *signal)

int	receivers (const char *signal) const

QObject *	sender () const

int	senderSignalIndex () const

virtual void	timerEvent (QTimerEvent *event)

Additional Inherited Members
Static Protected Member Functions inherited from QObject
QByteArray	normalizeSignalSlot (const char *signalSlot)

Protected Attributes inherited from QgsMapLayer
QString	mAbstract
	Description of the layer. More...

QString	mAttribution
	Attribution of the layer. More...

QString	mAttributionUrl

QString	mDataSource
	Data source description string, varies by layer type. More...

QString	mDataUrl
	DataUrl of the layer. More...

QString	mDataUrlFormat

QgsError	mError
	Error. More...

QgsRectangle	mExtent
	Extent of the layer. More...

QString	mKeywordList

QString	mLayerName
	Name of the layer - used for display. More...

QString	mLayerOrigName
	Original name of the layer. More...

QString	mLegendUrl
	WMS legend. More...

QString	mLegendUrlFormat

QString	mMetadataUrl
	MetadataUrl of the layer. More...

QString	mMetadataUrlFormat

QString	mMetadataUrlType

QString	mShortName

QString	mTitle

bool	mValid
	Indicates if the layer is valid and can be drawn. More...

Properties inherited from QgsMapLayer
QString	name
	Read property of QString layerName. More...

Properties inherited from QObject
	objectName

Detailed Description

This class provides qgis with the ability to render raster datasets onto the mapcanvas.

The qgsrasterlayer class makes use of gdal for data io, and thus supports any gdal supported format. The constructor attempts to infer what type of file (LayerType) is being opened - not in terms of the file format (tif, ascii grid etc.) but rather in terms of whether the image is a GRAYSCALE, PaletteD or Multiband,

Within the three allowable raster layer types, there are 8 permutations of how a layer can actually be rendered. These are defined in the DrawingStyle enum and consist of:

SingleBandGray -> a GRAYSCALE layer drawn as a range of gray colors (0-255) SingleBandPseudoColor -> a GRAYSCALE layer drawn using a pseudocolor algorithm PalettedSingleBandGray -> a PaletteD layer drawn in gray scale (using only one of the color components) PalettedSingleBandPseudoColor -> a PaletteD layer having only one of its color components rendered as psuedo color PalettedMultiBandColor -> a PaletteD image where the bands contains 24bit color info and 8 bits is pulled out per color MultiBandSingleBandGray -> a layer containing 2 or more bands, but using only one band to produce a grayscale image MultiBandSingleBandPseudoColor -> a layer containing 2 or more bands, but using only one band to produce a pseudocolor image MultiBandColor -> a layer containing 2 or more bands, mapped to the three RGBcolors. In the case of a multiband with only two bands, one band will have to be mapped to more than one color

Each of the above mentioned drawing styles is implemented in its own draw* function. Some of the drawing styles listed above require statistics about the layer such as the min / max / mean / stddev etc. statistics for a band can be gathered using the bandStatistics function. Note that statistics gathering is a slow process and every effort should be made to call this function as few times as possible. For this reason, qgsraster has a vector class member to store stats for each band. The constructor initialises this vector on startup, but only populates the band name and number fields.

Note that where bands are of gdal 'undefined' type, their values may exceed the renderable range of 0-255. Because of this a linear scaling histogram enhanceContrast is applied to undefined layers to normalise the data into the 0-255 range.

A qgsrasterlayer band can be referred to either by name or by number (base=1). It should be noted that band names as stored in datafiles may not be unique, and so the rasterlayer class appends the band number in brackets behind each band name.

Sample usage of the QgsRasterLayer class:

QString myFileNameQString = "/path/to/file";
QFileInfo myFileInfo(myFileNameQString);
QString myBaseNameQString = myFileInfo.baseName();
QgsRasterLayer *myRasterLayer = new QgsRasterLayer(myFileNameQString, myBaseNameQString);

In order to automate redrawing of a raster layer, you should like it to a map canvas like this :

QObject::connect( myRasterLayer, SIGNAL(repaintRequested()), mapCanvas, SLOT(refresh()) );

Once a layer has been created you can find out what type of layer it is (GrayOrUndefined, Palette or Multiband):

if (rasterLayer->rasterType()==QgsRasterLayer::Multiband)
{
  //do something
}
else if (rasterLayer->rasterType()==QgsRasterLayer::Palette)
{
  //do something
}
else // QgsRasterLayer::GrayOrUndefined
{
  //do something.
}

Raster layers can also have an arbitrary level of transparency defined, and have their color palettes inverted using the setTransparency and setInvertHistogram methods.

Pseudocolor images can have their output adjusted to a given number of standard deviations using the setStandardDeviations method.

The final area of functionality you may be interested in is band mapping. Band mapping allows you to choose arbitrary band -> color mappings and is applicable only to Palette and Multiband rasters, There are four mappings that can be made: red, green, blue and gray. Mappings are non-exclusive. That is a given band can be assigned to no, some or all color mappings. The constructor sets sensible defaults for band mappings but these can be overridden at run time using the setRedBandName, setGreenBandName, setBlueBandName and setGrayBandName methods.

Definition at line 145 of file qgsrasterlayer.h.

Member Enumeration Documentation

◆ ColorShadingAlgorithm

enum QgsRasterLayer::ColorShadingAlgorithm

This enumerator describes the types of shading that can be used.

Enumerator
UndefinedShader
PseudoColorShader
FreakOutShader
ColorRampShader
UserDefinedShader

Definition at line 196 of file qgsrasterlayer.h.

◆ LayerType

enum QgsRasterLayer::LayerType

This enumerator describes the type of raster layer.

Enumerator
GrayOrUndefined
Palette
Multiband
ColorLayer

Definition at line 206 of file qgsrasterlayer.h.

Constructor & Destructor Documentation

◆ QgsRasterLayer() [1/3]

QgsRasterLayer::QgsRasterLayer ( )

Constructor.

Provider is not set.

Definition at line 81 of file qgsrasterlayer.cpp.

◆ QgsRasterLayer() [2/3]

QgsRasterLayer::QgsRasterLayer	(	const QString &	path,
		const QString &	baseName = `QString::null`,
		bool	loadDefaultStyleFlag = `true`
	)

This is the constructor for the RasterLayer class.

The main tasks carried out by the constructor are:

-Load the rasters default style (.qml) file if it exists

-Populate the RasterStatsVector with initial values for each band.

-Calculate the layer extents

-Determine whether the layer is gray, paletted or multiband.

-Assign sensible defaults for the red, green, blue and gray bands.

Definition at line 91 of file qgsrasterlayer.cpp.

◆ QgsRasterLayer() [3/3]

QgsRasterLayer::QgsRasterLayer	(	const QString &	uri,
		const QString &	baseName,
		const QString &	providerKey,
		bool	loadDefaultStyleFlag = `true`
	)

[ data provider interface ] Constructor in provider mode

Todo:: Rename into a general constructor when the old raster interface is retired parameter dummy is just there to distinguish this function signature from the old non-provider one.

Definition at line 123 of file qgsrasterlayer.cpp.

◆ ~QgsRasterLayer()

QgsRasterLayer::~QgsRasterLayer ( )

The destructor.

Definition at line 155 of file qgsrasterlayer.cpp.

Member Function Documentation

◆ bandCount()

int QgsRasterLayer::bandCount ( ) const

Get the number of bands in this layer.

Definition at line 216 of file qgsrasterlayer.cpp.

◆ bandName()

const QString QgsRasterLayer::bandName ( int theBandNoInt )

Get the name of a band given its number.

Definition at line 222 of file qgsrasterlayer.cpp.

◆ brightnessFilter()

QgsBrightnessContrastFilter* QgsRasterLayer::brightnessFilter ( ) const

inline

Definition at line 238 of file qgsrasterlayer.h.

◆ createMapRenderer()

QgsMapLayerRenderer * QgsRasterLayer::createMapRenderer ( QgsRenderContext & rendererContext )

overridevirtual

Return new instance of QgsMapLayerRenderer that will be used for rendering of given context.

Note: added in 2.4

Reimplemented from QgsMapLayer.

Definition at line 256 of file qgsrasterlayer.cpp.

◆ dataProvider() [1/2]

QgsRasterDataProvider * QgsRasterLayer::dataProvider ( )

Returns the data provider.

Returns: 0 if not using the data provider model (i.e. directly using GDAL)

Definition at line 235 of file qgsrasterlayer.cpp.

◆ dataProvider() [2/2]

const QgsRasterDataProvider * QgsRasterLayer::dataProvider ( ) const

Returns the data provider in a const-correct manner.

Note: available in python bindings as constDataProvider()

Returns: 0 if not using the data provider model (i.e. directly using GDAL)

Definition at line 243 of file qgsrasterlayer.cpp.

◆ draw() [1/2]

bool QgsRasterLayer::draw ( QgsRenderContext & rendererContext )

overridevirtual

This is called when the view on the raster layer needs to be redrawn.

Reimplemented from QgsMapLayer.

Definition at line 261 of file qgsrasterlayer.cpp.

◆ draw() [2/2]

void QgsRasterLayer::draw	(	QPainter *	theQPainter,
		QgsRasterViewPort *	myRasterViewPort,
		const QgsMapToPixel *	theQgsMapToPixel = `nullptr`
	)

This is an overloaded version of the draw() function that is called by both draw() and thumbnailAsPixmap.

Definition at line 277 of file qgsrasterlayer.cpp.

◆ height()

int QgsRasterLayer::height ( ) const

Accessor that returns the height of the (unclipped) raster.

Definition at line 1567 of file qgsrasterlayer.cpp.

◆ hueSaturationFilter()

QgsHueSaturationFilter* QgsRasterLayer::hueSaturationFilter ( ) const

inline

Definition at line 239 of file qgsrasterlayer.h.

◆ isSpatial()

virtual bool QgsRasterLayer::isSpatial ( ) const

inlineoverridevirtual

Returns true if the layer is considered a spatial layer, ie it has some form of geometry associated with it.

Note: added in QGIS 2.16

Reimplemented from QgsMapLayer.

Definition at line 283 of file qgsrasterlayer.h.

◆ isValidRasterFileName() [1/2]

bool QgsRasterLayer::isValidRasterFileName	(	const QString &	theFileNameQString,
		QString &	retError
	)

static

This helper checks to see whether the file name appears to be a valid raster file name.

If the file name looks like it could be valid, but some sort of error occurs in processing the file, the error is returned in retError.

Definition at line 170 of file qgsrasterlayer.cpp.

◆ isValidRasterFileName() [2/2]

bool QgsRasterLayer::isValidRasterFileName ( const QString & theFileNameQString )

static

Definition at line 183 of file qgsrasterlayer.cpp.

◆ lastModified()

QDateTime QgsRasterLayer::lastModified ( const QString & name )

static

Return time stamp for given file name.

Definition at line 189 of file qgsrasterlayer.cpp.

◆ legendSymbologyItems()

QgsLegendColorList QgsRasterLayer::legendSymbologyItems ( ) const

Returns a list with classification items (Text and color)

Definition at line 308 of file qgsrasterlayer.cpp.

◆ metadata()

QString QgsRasterLayer::metadata ( )

overridevirtual

Obtain GDAL Metadata for this layer.

Reimplemented from QgsMapLayer.

Definition at line 319 of file qgsrasterlayer.cpp.

◆ onProgress

void QgsRasterLayer::onProgress	(	int	theType,
		double	theProgress,
		const QString &	theMessage
	)

slot

receive progress signal from provider

Definition at line 1210 of file qgsrasterlayer.cpp.

◆ paletteAsPixmap()

QPixmap QgsRasterLayer::paletteAsPixmap ( int theBandNumber = 1 )

Get an 100x100 pixmap of the color palette.

If the layer has no palette a white pixmap will be returned

Parameters

theBandNumber the number of the band to use for generating a pixmap of the associated palette

Returns: a 100x100 pixel QPixmap of the bands palette

Definition at line 535 of file qgsrasterlayer.cpp.

◆ pipe()

QgsRasterPipe* QgsRasterLayer::pipe ( )

inline

Get raster pipe.

Definition at line 242 of file qgsrasterlayer.h.

◆ previewAsImage()

QImage QgsRasterLayer::previewAsImage	(	QSize	size,
		const QColor &	bgColor = `Qt::white`,
		QImage::Format	format = `QImage::Format_ARGB32_Premultiplied`
	)

Draws a preview of the rasterlayer into a QImage.

Note: added in 2.4

Definition at line 1154 of file qgsrasterlayer.cpp.

◆ previewAsPixmap()

QPixmap QgsRasterLayer::previewAsPixmap	(	QSize	size,
		const QColor &	bgColor = `Qt::white`
	)

Draws a preview of the rasterlayer into a pixmap.

Deprecated:: use previewAsImage() for rendering with QGIS>=2.4

Definition at line 1103 of file qgsrasterlayer.cpp.

◆ progressUpdate

void QgsRasterLayer::progressUpdate ( int theValue )

signal

Signal for notifying listeners of long running processes.

◆ providerType()

QString QgsRasterLayer::providerType ( ) const

[ data provider interface ] Which provider is being used for this Raster Layer?

Definition at line 589 of file qgsrasterlayer.cpp.

◆ rasterType()

LayerType QgsRasterLayer::rasterType ( )

inline

Accessor for raster layer type (which is a read only property)

Definition at line 229 of file qgsrasterlayer.h.

◆ rasterUnitsPerPixelX()

double QgsRasterLayer::rasterUnitsPerPixelX ( )

Returns the number of raster units per each raster pixel.

In a world file, this is normally the first row (without the sign)

Returns: the horizontal units per pixel as reported in the GDAL geotramsform[1]

Definition at line 597 of file qgsrasterlayer.cpp.

◆ rasterUnitsPerPixelY()

double QgsRasterLayer::rasterUnitsPerPixelY ( )

Definition at line 612 of file qgsrasterlayer.cpp.

◆ readStyle()

bool QgsRasterLayer::readStyle	(	const QDomNode &	node,
		QString &	errorMessage
	)

overrideprotectedvirtual

Read the style information for the current layer from the Dom node supplied.

Reimplemented from QgsMapLayer.

Definition at line 1317 of file qgsrasterlayer.cpp.

◆ readSymbology()

bool QgsRasterLayer::readSymbology	(	const QDomNode &	node,
		QString &	errorMessage
	)

overrideprotectedvirtual

Read the symbology for the current layer from the Dom node supplied.

Implements QgsMapLayer.

Definition at line 1228 of file qgsrasterlayer.cpp.

◆ readXml()

bool QgsRasterLayer::readXml ( const QDomNode & layer_node )

overrideprotectedvirtual

Reads layer specific state from project file Dom node.

Raster layer project file XML of form:

Note: Called by QgsMapLayer::readXML().

Note: Make sure to read the file first so stats etc are initialized properly!

Reimplemented from QgsMapLayer.

Definition at line 1328 of file qgsrasterlayer.cpp.

◆ reload()

void QgsRasterLayer::reload ( )

overridevirtual

Synchronises with changes in the datasource.

Reimplemented from QgsMapLayer.

Definition at line 248 of file qgsrasterlayer.cpp.

◆ renderer()

QgsRasterRenderer* QgsRasterLayer::renderer ( ) const

inline

Definition at line 233 of file qgsrasterlayer.h.

◆ resampleFilter()

QgsRasterResampleFilter* QgsRasterLayer::resampleFilter ( ) const

inline

Set raster resample filter.

Takes ownership of the resample filter object

Definition at line 236 of file qgsrasterlayer.h.

◆ setContrastEnhancement()

void QgsRasterLayer::setContrastEnhancement	(	QgsContrastEnhancement::ContrastEnhancementAlgorithm	theAlgorithm,
		QgsRaster::ContrastEnhancementLimits	theLimits = `QgsRaster::ContrastEnhancementMinMax`,
		const QgsRectangle &	theExtent = `QgsRectangle()`,
		int	theSampleSize = `SAMPLE_SIZE`,
		bool	theGenerateLookupTableFlag = `true`
	)

Set contrast enhancement algorithm.

Parameters

theAlgorithm	Contrast enhancement algorithm
theLimits	Limits
theExtent	Extent used to calculate limits, if empty, use full layer extent
theSampleSize	Size of data sample to calculate limits, if 0, use full resolution
theGenerateLookupTableFlag	Generate lookup table.

Definition at line 854 of file qgsrasterlayer.cpp.

◆ setDataProvider()

void QgsRasterLayer::setDataProvider ( const QString & provider )

[ data provider interface ] Set the data provider

Definition at line 634 of file qgsrasterlayer.cpp.

◆ setDefaultContrastEnhancement()

void QgsRasterLayer::setDefaultContrastEnhancement ( )

Set default contrast enhancement.

Definition at line 942 of file qgsrasterlayer.cpp.

◆ setDrawingStyle()

void QgsRasterLayer::setDrawingStyle ( const QString & theDrawingStyleQString )

Overloaded version of the above function for convenience when restoring from xml.

Implemented mainly for serialisation / deserialisation of settings to xml.

Deprecated:: Deprecated since QGIS 2.10.

Use setRendererForDrawingStyle() or directly setRenderer()

Note: May be deprecated in the future! Use setDrawingStyle( DrawingStyle ) instead.

Definition at line 998 of file qgsrasterlayer.cpp.

◆ setLayerOrder()

void QgsRasterLayer::setLayerOrder ( const QStringList & layers )

overridevirtual

Reorders the previously selected sublayers of this layer from bottom to top.

(Useful for providers that manage their own layers, such as WMS)

Reimplemented from QgsMapLayer.

Definition at line 1051 of file qgsrasterlayer.cpp.

◆ setRenderer()

void QgsRasterLayer::setRenderer ( QgsRasterRenderer * theRenderer )

Set raster renderer.

Takes ownership of the renderer object

Definition at line 1074 of file qgsrasterlayer.cpp.

◆ setSubLayerVisibility()

void QgsRasterLayer::setSubLayerVisibility	(	const QString &	name,
		bool	vis
	)

overridevirtual

Set the visibility of the given sublayer name.

Reimplemented from QgsMapLayer.

Definition at line 1063 of file qgsrasterlayer.cpp.

◆ showProgress()

void QgsRasterLayer::showProgress ( int theValue )

[ data provider interface ] A wrapper function to emit a progress update signal

Definition at line 1083 of file qgsrasterlayer.cpp.

◆ showStatusMessage

void QgsRasterLayer::showStatusMessage ( const QString & theMessage )

slot

Definition at line 1089 of file qgsrasterlayer.cpp.

◆ subLayers()

QStringList QgsRasterLayer::subLayers ( ) const

overridevirtual

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

Reimplemented from QgsMapLayer.

Definition at line 1098 of file qgsrasterlayer.cpp.

◆ timestamp()

virtual QDateTime QgsRasterLayer::timestamp ( ) const

inlineoverridevirtual

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

Reimplemented from QgsMapLayer.

Definition at line 349 of file qgsrasterlayer.h.

◆ updateProgress

void QgsRasterLayer::updateProgress	(	int	theProgress,
		int	theMax
	)

slot

Deprecated:: in 2.4 - does nothing

Definition at line 1204 of file qgsrasterlayer.cpp.

◆ width()

int QgsRasterLayer::width ( ) const

Accessor that returns the width of the (unclipped) raster.

Definition at line 1561 of file qgsrasterlayer.cpp.

◆ writeStyle()

bool QgsRasterLayer::writeStyle	(	QDomNode &	node,
		QDomDocument &	doc,
		QString &	errorMessage
	)		const

overrideprotectedvirtual

Write the style for the layer into the docment provided.

Reimplemented from QgsMapLayer.

Definition at line 1496 of file qgsrasterlayer.cpp.

◆ writeSymbology()

bool QgsRasterLayer::writeSymbology	(	QDomNode &	layer_node,
		QDomDocument &	doc,
		QString &	errorMessage
	)		const

overrideprotectedvirtual

Write the symbology for the layer into the docment provided.

Implements QgsMapLayer.

Definition at line 1469 of file qgsrasterlayer.cpp.

◆ writeXml()

bool QgsRasterLayer::writeXml	(	QDomNode &	layer_node,
		QDomDocument &	doc
	)

overrideprotectedvirtual

Write layer specific state to project file Dom node.

Reimplemented from QgsMapLayer.

Definition at line 1506 of file qgsrasterlayer.cpp.

Member Data Documentation

◆ CUMULATIVE_CUT_LOWER

const double QgsRasterLayer::CUMULATIVE_CUT_LOWER = 0.02

static

Default cumulative cut lower limit.

Definition at line 150 of file qgsrasterlayer.h.

◆ CUMULATIVE_CUT_UPPER

const double QgsRasterLayer::CUMULATIVE_CUT_UPPER = 0.98

static

Default cumulative cut upper limit.

Definition at line 153 of file qgsrasterlayer.h.

◆ SAMPLE_SIZE

const double QgsRasterLayer::SAMPLE_SIZE = 250000

static

Default sample size (number of pixels) for estimated statistics/histogram calculation.

Definition at line 156 of file qgsrasterlayer.h.

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

/tmp/buildd/qgis-2.18.21+99unstable/src/core/raster/qgsrasterlayer.h
/tmp/buildd/qgis-2.18.21+99unstable/src/core/raster/qgsrasterlayer.cpp

Public Types

Public Slots

Signals

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Member Functions

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ ColorShadingAlgorithm

◆ LayerType

Constructor & Destructor Documentation

◆ QgsRasterLayer() [1/3]

◆ QgsRasterLayer() [2/3]

◆ QgsRasterLayer() [3/3]

◆ ~QgsRasterLayer()

Member Function Documentation

◆ bandCount()

◆ bandName()

◆ brightnessFilter()

◆ createMapRenderer()

◆ dataProvider() [1/2]

◆ dataProvider() [2/2]

◆ draw() [1/2]

◆ draw() [2/2]

◆ height()

◆ hueSaturationFilter()

◆ isSpatial()

◆ isValidRasterFileName() [1/2]

◆ isValidRasterFileName() [2/2]

◆ lastModified()

◆ legendSymbologyItems()

◆ metadata()

◆ onProgress

◆ paletteAsPixmap()

◆ pipe()

◆ previewAsImage()

◆ previewAsPixmap()

◆ progressUpdate

◆ providerType()

◆ rasterType()

◆ rasterUnitsPerPixelX()

◆ rasterUnitsPerPixelY()

◆ readStyle()

◆ readSymbology()

◆ readXml()

◆ reload()

◆ renderer()

◆ resampleFilter()

◆ setContrastEnhancement()

◆ setDataProvider()

◆ setDefaultContrastEnhancement()

◆ setDrawingStyle()

◆ setLayerOrder()

◆ setRenderer()

◆ setSubLayerVisibility()

◆ showProgress()

◆ showStatusMessage

◆ subLayers()

◆ timestamp()

◆ updateProgress

◆ width()

◆ writeStyle()

◆ writeSymbology()

◆ writeXml()

Member Data Documentation

◆ CUMULATIVE_CUT_LOWER

◆ CUMULATIVE_CUT_UPPER

◆ SAMPLE_SIZE