QGIS API Documentation  3.3.0-Master (c515a66)
Public Types | Signals | Public Member Functions | Static Public Member Functions | Protected Member Functions | Protected Attributes | List of all members
QgsRasterDataProvider Class Referenceabstract

Base class for raster data providers. More...

#include <qgsrasterdataprovider.h>

Inheritance diagram for QgsRasterDataProvider:
Inheritance graph
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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 ()
 This is emitted whenever an asynchronous operation has finished and the data should be redrawn. More...
 
void fullExtentCalculated ()
 This is emitted whenever the worker thread has fully calculated the PostGIS extents for this layer, and its event has been received by this provider. More...
 
void notify (const QString &msg)
 Emitted when 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...
 
QgsRasterBlockblock (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< QgsRasterPyramidbuildPyramidList (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...
 
QgsRasterInterfaceclone () 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::ColorRampItemcolorTable (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 QgsImageFetchergetLegendGraphicFetcher (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 QgsRasterInterfaceinput () 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 QgsRasterInterfacesourceInput () const
 Gets source / raw input, the first in pipe, usually provider. More...
 
virtual QgsRasterInterfacesourceInput ()
 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 QgsRasterDataProvidercreate (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< QgsRasterRangeListmUserNoDataValue
 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< QgsRasterHistogrammHistograms
 List of cached histograms, all bands mixed. More...
 
QgsRasterInterfacemInput = nullptr
 
bool mOn = true
 
QList< QgsRasterBandStatsmStatistics
 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

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
overviewListused 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
scaleOptional parameter that is the Scale of the layer
forceRefreshOptional bool parameter to force refresh getLegendGraphic call
visibleExtentVisible 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
mapSettingsmap 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
pointcoordinates in data source CRS
formatresult format
boundingBoxcontext bounding box
widthcontext width
heightcontext height
dpicontext 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
bandNoband number
noDataValueno 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: