QgsRasterLayer Class Reference

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	showStatusMessage (const QString &theMessage)
Q_DECL_DEPRECATED void	updateProgress (int, int)
void	onProgress (int, double, QString)
	receive progress signal from provider
Public Slots inherited from QgsMapLayer
virtual void	invalidTransformInput ()
	Event handler for when a coordinate transform fails due to bad vertex error.
void	setMinimumScale (float theMinScale)
	Accessor and mutator for the minimum scale denominator member.
float	minimumScale () const
void	setMaximumScale (float theMaxScale)
	Accessor and mutator for the maximum scale denominator member.
float	maximumScale () const
void	toggleScaleBasedVisibility (bool theVisibilityFlag)
	Accessor and mutator for the scale based visilibility flag.
bool	hasScaleBasedVisibility () const
Q_DECL_DEPRECATED void	clearCacheImage ()
	Clear cached image.
void	triggerRepaint ()
	Will advice the map canvas (and any other interested party) that this layer requires to be repainted.

Signals
void	progressUpdate (int theValue)
	Signal for notifying listeners of long running processes.
void	dataChanged ()
	This is emitted whenever data or metadata (e.g.
Signals inherited from QgsMapLayer
void	drawingProgress (int theProgress, int theTotalSteps)
void	statusChanged (QString theStatus)
	Emit a signal with status (e.g.
void	layerNameChanged ()
	Emit a signal that the layer name has been changed.
void	layerCrsChanged ()
	Emit a signal that layer's CRS has been reset.
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.
void	screenUpdateRequested ()
void	recalculateExtents ()
	This is used to send a request that any mapcanvas using this layer update its extents.
void	dataChanged ()
	data of layer changed
void	blendModeChanged (const QPainter::CompositionMode &blendMode)
	Signal emitted when the blend mode is changed, through QgsMapLayer::setBlendMode()
void	rendererChanged ()
	Signal emitted when renderer is changed.
void	legendChanged ()
	Signal emitted when legend of the layer has changed.

Public Member Functions
	QgsRasterLayer ()
	Constructor.
	QgsRasterLayer (const QString &path, const QString &baseName=QString::null, bool loadDefaultStyleFlag=true)
	This is the constructor for the RasterLayer class.
	QgsRasterLayer (const QString &uri, const QString &baseName, const QString &providerKey, bool loadDefaultStyleFlag=true)
	[ data provider interface ] Constructor in provider mode
	~QgsRasterLayer ()
	The destructor.
void	setDataProvider (const QString &provider)
	[ data provider interface ] Set the data provider
LayerType	rasterType ()
	Accessor for raster layer type (which is a read only property)
void	setRenderer (QgsRasterRenderer *theRenderer)
	Set raster renderer.
QgsRasterRenderer *	renderer () const
QgsRasterResampleFilter *	resampleFilter () const
	Set raster resample filter.
QgsBrightnessContrastFilter *	brightnessFilter () const
QgsHueSaturationFilter *	hueSaturationFilter () const
QgsRasterPipe *	pipe ()
	Get raster pipe.
int	width () const
	Accessor that returns the width of the (unclipped) raster.
int	height () const
	Accessor that returns the height of the (unclipped) raster.
int	bandCount () const
	Get the number of bands in this layer.
const QString	bandName (int theBandNoInt)
	Get the name of a band given its number.
QgsRasterDataProvider *	dataProvider ()
	Returns the data provider.
const QgsRasterDataProvider *	dataProvider () const
	Returns the data provider in a const-correct manner.
virtual void	reload ()
	Synchronises with changes in the datasource.
virtual QgsMapLayerRenderer *	createMapRenderer (QgsRenderContext &rendererContext)
	Return new instance of QgsMapLayerRenderer that will be used for rendering of given context.
bool	draw (QgsRenderContext &rendererContext)
	This is called when the view on the raster layer needs to be redrawn.
void	draw (QPainter *theQPainter, QgsRasterViewPort *myRasterViewPort, const QgsMapToPixel *theQgsMapToPixel=0)
	This is an overloaded version of the draw() function that is called by both draw() and thumbnailAsPixmap.
QgsLegendColorList	legendSymbologyItems () const
	Returns a list with classification items (Text and color)
QString	metadata ()
	Obtain GDAL Metadata for this layer.
QPixmap	paletteAsPixmap (int theBandNumber=1)
	Get an 100x100 pixmap of the color palette.
QString	providerType () const
	[ data provider interface ] Which provider is being used for this Raster Layer?
double	rasterUnitsPerPixelX ()
	Returns the number of raster units per each raster pixel.
double	rasterUnitsPerPixelY ()
void	setContrastEnhancement (QgsContrastEnhancement::ContrastEnhancementAlgorithm theAlgorithm, QgsRaster::ContrastEnhancementLimits theLimits=QgsRaster::ContrastEnhancementMinMax, QgsRectangle theExtent=QgsRectangle(), int theSampleSize=SAMPLE_SIZE, bool theGenerateLookupTableFlag=true)
	Set contrast enhancement algorithm.
void	setDefaultContrastEnhancement ()
	Set default contrast enhancement.
void	setDrawingStyle (const QString &theDrawingStyleQString)
	Overloaded version of the above function for convenience when restoring from xml.
void	showProgress (int theValue)
	[ data provider interface ] A wrapper function to emit a progress update signal
virtual QStringList	subLayers () const
	Returns the sublayers of this layer - Useful for providers that manage their own layers, such as WMS.
Q_DECL_DEPRECATED QPixmap	previewAsPixmap (QSize size, QColor bgColor=Qt::white)
	Draws a preview of the rasterlayer into a pixmap.
QImage	previewAsImage (QSize size, QColor bgColor=Qt::white, QImage::Format format=QImage::Format_ARGB32_Premultiplied)
	Draws a preview of the rasterlayer into a QImage.
virtual void	setLayerOrder (const QStringList &layers)
	Reorders the previously selected sublayers of this layer from bottom to top.
virtual void	setSubLayerVisibility (QString name, bool vis)
	Set the visibility of the given sublayer name.
virtual QDateTime	timestamp () const
	Time stamp of data source in the moment when data/metadata were loaded by provider.
Public Member Functions inherited from QgsMapLayer
	QgsMapLayer (QgsMapLayer::LayerType type=VectorLayer, QString lyrname=QString::null, QString source=QString::null)
	Constructor.
virtual	~QgsMapLayer ()
	Destructor.
QgsMapLayer::LayerType	type () const
	Get the type of the layer.
QString	id () const
	Get this layer's unique ID, this ID is used to access this layer from map layer registry.
void	setLayerName (const QString &name)
	Set the display name of the layer.
const QString &	name () const
	Get the display name of the layer.
const QString &	originalName () const
	Get the original name of the layer.
void	setTitle (const QString &title)
const QString &	title () const
void	setAbstract (const QString &abstract)
const QString &	abstract () const
void	setKeywordList (const QString &keywords)
const QString &	keywordList () const
void	setDataUrl (const QString &dataUrl)
const QString &	dataUrl () const
void	setDataUrlFormat (const QString &dataUrlFormat)
const QString &	dataUrlFormat () const
void	setAttribution (const QString &attrib)
const QString &	attribution () const
void	setAttributionUrl (const QString &attribUrl)
const QString &	attributionUrl () const
void	setMetadataUrl (const QString &metaUrl)
const QString &	metadataUrl () const
void	setMetadataUrlType (const QString &metaUrlType)
const QString &	metadataUrlType () const
void	setMetadataUrlFormat (const QString &metaUrlFormat)
const QString &	metadataUrlFormat () const
void	setBlendMode (const QPainter::CompositionMode &blendMode)
	Write blend mode for layer.
QPainter::CompositionMode	blendMode () const
	Read blend mode for layer.
virtual void	drawLabels (QgsRenderContext &rendererContext)
	Draw labels.
virtual QgsRectangle	extent ()
	Return the extent of the layer.
bool	isValid ()
QString	publicSource () const
const QString &	source () const
	Returns the source for the layer.
virtual bool	isEditable () const
	True if the layer can be edited.
bool	readLayerXML (const QDomElement &layerElement)
	sets state from Dom document
bool	writeLayerXML (QDomElement &layerElement, QDomDocument &document, QString relativeBasePath=QString::null)
	stores state in Dom node
void	setCustomProperty (const QString &key, const QVariant &value)
	Set a custom property for layer.
QVariant	customProperty (const QString &value, const QVariant &defaultValue=QVariant()) const
	Read a custom property from layer.
void	removeCustomProperty (const QString &key)
	Remove a custom property from layer.
virtual Q_DECL_DEPRECATED QString	lastErrorTitle ()
virtual Q_DECL_DEPRECATED QString	lastError ()
virtual QgsError	error () const
	Get current status error.
const QgsCoordinateReferenceSystem &	crs () const
	Returns layer's spatial reference system.
void	setCrs (const QgsCoordinateReferenceSystem &srs, bool emitSignal=true)
	Sets layer's spatial reference system.
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)
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)
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)
virtual bool	loadNamedStyleFromDb (const QString &db, const QString &theURI, QString &qml)
virtual void	exportNamedStyle (QDomDocument &doc, QString &errorMsg)
	Export the properties of this layer as named style in a QDomDocument.
virtual void	exportSldStyle (QDomDocument &doc, QString &errorMsg)
	Export the properties of this layer as SLD style in a QDomDocument.
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)
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)
virtual QString	saveSldStyle (const QString &theURI, bool &theResultFlag)
virtual QString	loadSldStyle (const QString &theURI, bool &theResultFlag)
virtual bool	readSld (const QDomNode &node, QString &errorMessage)
QUndoStack *	undoStack ()
	Return pointer to layer's undo stack.
void	setLegendUrl (const QString &legendUrl)
const QString &	legendUrl () const
void	setLegendUrlFormat (const QString &legendUrlFormat)
const QString &	legendUrlFormat () const
Q_DECL_DEPRECATED QImage *	cacheImage ()
Q_DECL_DEPRECATED void	setCacheImage (QImage *)
virtual Q_DECL_DEPRECATED void	onCacheImageDelete ()
void	setLegend (QgsMapLayerLegend *legend)
	Assign a legend controller to the map layer.
QgsMapLayerLegend *	legend () const
	Can be null.

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.
static bool	isValidRasterFileName (const QString &theFileNameQString)
static QDateTime	lastModified (const QString &name)
	Return time stamp for given file name.
Static Public Member Functions inherited from QgsMapLayer
static QDomDocument	asLayerDefinition (QList< QgsMapLayer * > layers, QString relativeBasePath=QString::null)
	Returns the given layer as a layer definition document Layer definitions store the data source as well as styling and custom properties.
static QList< QgsMapLayer * >	fromLayerDefinition (QDomDocument &document)
	Creates a new layer from a layer defininition document.
static QList< QgsMapLayer * >	fromLayerDefinitionFile (const QString qlrfile)
static QString	capitaliseLayerName (const QString &name)
	A convenience function to (un)capitalise the layer name.

Static Public Attributes
static const double	CUMULATIVE_CUT_LOWER = 0.02
	Default cumulative cut lower limit.
static const double	CUMULATIVE_CUT_UPPER = 0.98
	Default cumulative cut upper limit.
static const double	SAMPLE_SIZE = 250000
	Default sample size (number of pixels) for estimated statistics/histogram calculation.

Protected Member Functions
bool	readSymbology (const QDomNode &node, QString &errorMessage)
	Read the symbology for the current layer from the Dom node supplied.
bool	readXml (const QDomNode &layer_node)
	Reads layer specific state from project file Dom node.
bool	writeSymbology (QDomNode &, QDomDocument &doc, QString &errorMessage) const
	Write the symbology for the layer into the docment provided.
bool	writeXml (QDomNode &layer_node, QDomDocument &doc)
	Write layer specific state to project file Dom node.
Protected Member Functions inherited from QgsMapLayer
virtual void	setExtent (const QgsRectangle &rect)
	Set the extent.
void	setValid (bool valid)
	set whether layer is valid or not - should be used in constructor.
void	readCustomProperties (const QDomNode &layerNode, const QString &keyStartsWith="")
	Read custom properties from project file.
void	writeCustomProperties (QDomNode &layerNode, QDomDocument &doc) const
	Write custom properties to project file.
void	connectNotify (const char *signal)
	debugging member - invoked when a connect() is made to this object
void	appendError (const QgsErrorMessage &theMessage)
	Add error message.
void	setError (const QgsError &theError)
	Set error message.

Additional Inherited Members
Protected Attributes inherited from QgsMapLayer
QgsRectangle	mExtent
	Extent of the layer.
bool	mValid
	Indicates if the layer is valid and can be drawn.
QString	mDataSource
	data source description string, varies by layer type
QString	mLayerName
	Name of the layer - used for display.
QString	mLayerOrigName
	Original name of the layer.
QString	mTitle
QString	mAbstract
	Description of the layer.
QString	mKeywordList
QString	mDataUrl
	DataUrl of the layer.
QString	mDataUrlFormat
QString	mAttribution
	Attribution of the layer.
QString	mAttributionUrl
QString	mMetadataUrl
	MetadataUrl of the layer.
QString	mMetadataUrlType
QString	mMetadataUrlFormat
QString	mLegendUrl
	WMS legend.
QString	mLegendUrlFormat
QgsError	mError
	Error.

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()) );

A raster layer can also export its legend as a pixmap:

QPixmap myQPixmap = myRasterLayer->legendPixmap();

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.
}

You can combine layer type detection with the setDrawingStyle method to override the default drawing style assigned when a layer is loaded:

if (rasterLayer->rasterType()==QgsRasterLayer::Multiband)
{
   myRasterLayer->setDrawingStyle(QgsRasterLayer::MultiBandSingleBandPseudoColor);
}
else if (rasterLayer->rasterType()==QgsRasterLayer::Palette)
{
  myRasterLayer->setDrawingStyle(QgsRasterLayer::PalettedSingleBandPseudoColor);
}
else // QgsRasterLayer::GrayOrUndefined
{
  myRasterLayer->setDrawingStyle(QgsRasterLayer::SingleBandPseudoColor);
}

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.

Member Enumeration Documentation

enum QgsRasterLayer::ColorShadingAlgorithm

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

Enumerator:

UndefinedShader
PseudoColorShader
FreakOutShader
ColorRampShader
UserDefinedShader

enum QgsRasterLayer::LayerType

This enumerator describes the type of raster layer.

Enumerator:

GrayOrUndefined
Palette
Multiband
ColorLayer

Constructor & Destructor Documentation

QgsRasterLayer::QgsRasterLayer

(

)

Constructor.

Provider is not set.

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.

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.

QgsRasterLayer::~QgsRasterLayer

(

)

The destructor.

Member Function Documentation

int QgsRasterLayer::bandCount

(

)

const

Get the number of bands in this layer.

const QString QgsRasterLayer::bandName

(

int

theBandNoInt

)

Get the name of a band given its number.

QgsBrightnessContrastFilter* QgsRasterLayer::brightnessFilter ( ) const

inline

QgsMapLayerRenderer * QgsRasterLayer::createMapRenderer ( QgsRenderContext &  rendererContext )

virtual

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

Note

added in 2.4

Reimplemented from QgsMapLayer.

void QgsRasterLayer::dataChanged ( )

signal

This is emitted whenever data or metadata (e.g.

color table, extent) has changed

QgsRasterDataProvider * QgsRasterLayer::dataProvider

(

)

Returns the data provider.

Returns

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

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)

bool QgsRasterLayer::draw ( QgsRenderContext &  rendererContext )

virtual

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

Reimplemented from QgsMapLayer.

void QgsRasterLayer::draw	(	QPainter *	theQPainter,
		QgsRasterViewPort *	myRasterViewPort,
		const QgsMapToPixel *	theQgsMapToPixel = 0
	)

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

int QgsRasterLayer::height

(

)

const

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

QgsHueSaturationFilter* QgsRasterLayer::hueSaturationFilter ( ) const

inline

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.

bool QgsRasterLayer::isValidRasterFileName ( const QString &  theFileNameQString )

static

QDateTime QgsRasterLayer::lastModified ( const QString &  name )

static

Return time stamp for given file name.

QgsLegendColorList QgsRasterLayer::legendSymbologyItems

(

)

const

Returns a list with classification items (Text and color)

QString QgsRasterLayer::metadata ( )

virtual

Obtain GDAL Metadata for this layer.

Reimplemented from QgsMapLayer.

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

slot

receive progress signal from provider

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

QgsRasterPipe* QgsRasterLayer::pipe ( )

inline

Get raster pipe.

QImage QgsRasterLayer::previewAsImage	(	QSize	size,
		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

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

Draws a preview of the rasterlayer into a pixmap.

Note

- use previewAsImage() for rendering with QGIS>=2.4

void QgsRasterLayer::progressUpdate ( int  theValue )

signal

Signal for notifying listeners of long running processes.

QString QgsRasterLayer::providerType

(

)

const

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

LayerType QgsRasterLayer::rasterType ( )

inline

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

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]

double QgsRasterLayer::rasterUnitsPerPixelY

(

)

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

protectedvirtual

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

Implements QgsMapLayer.

bool QgsRasterLayer::readXml ( const QDomNode &  layer_node )

protectedvirtual

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 initialised properly!

Reimplemented from QgsMapLayer.

void QgsRasterLayer::reload ( )

virtual

Synchronises with changes in the datasource.

Reimplemented from QgsMapLayer.

QgsRasterRenderer* QgsRasterLayer::renderer ( ) const

inline

QgsRasterResampleFilter* QgsRasterLayer::resampleFilter ( ) const

inline

Set raster resample filter.

Takes ownership of the resample filter object

void QgsRasterLayer::setContrastEnhancement	(	QgsContrastEnhancement::ContrastEnhancementAlgorithm	theAlgorithm,
		QgsRaster::ContrastEnhancementLimits	theLimits = QgsRaster::ContrastEnhancementMinMax,
		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 llokup table.

void QgsRasterLayer::setDataProvider

(

const QString &

provider

)

[ data provider interface ] Set the data provider

void QgsRasterLayer::setDefaultContrastEnhancement

(

)

Set default contrast enhancement.

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.

Note

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

void QgsRasterLayer::setLayerOrder ( const QStringList &  layers )

virtual

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.

void QgsRasterLayer::setRenderer

(

QgsRasterRenderer *

theRenderer

)

Set raster renderer.

Takes ownership of the renderer object

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

virtual

Set the visibility of the given sublayer name.

Reimplemented from QgsMapLayer.

void QgsRasterLayer::showProgress

(

int

theValue

)

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

void QgsRasterLayer::showStatusMessage ( const QString &  theMessage )

slot

QStringList QgsRasterLayer::subLayers ( ) const

virtual

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

Reimplemented from QgsMapLayer.

virtual QDateTime QgsRasterLayer::timestamp ( ) const

inlinevirtual

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

Reimplemented from QgsMapLayer.

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

slot

Deprecated:

in 2.4 - does nothing

int QgsRasterLayer::width

(

)

const

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

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

protectedvirtual

Write the symbology for the layer into the docment provided.

Implements QgsMapLayer.

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

protectedvirtual

Write layer specific state to project file Dom node.

Reimplemented from QgsMapLayer.

Member Data Documentation

const double QgsRasterLayer::CUMULATIVE_CUT_LOWER = 0.02

static

Default cumulative cut lower limit.

const double QgsRasterLayer::CUMULATIVE_CUT_UPPER = 0.98

static

Default cumulative cut upper limit.

const double QgsRasterLayer::SAMPLE_SIZE = 250000

static

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

---

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

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