Subgroup: Raster

Class: QgsRasterDataProvider

class qgis.core.QgsRasterDataProvider

Bases: qgis._core.QgsDataProvider, qgis._core.QgsRasterInterface

QgsRasterDataProvider(uri: str, options: QgsDataProvider.ProviderOptions = 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.

Base class for raster data providers.

Methods

appendError
bandOffset Read band offset for raster value
bandScale Read band scale for raster value
block Read block of data using given extent and size.
buildPyramidList Returns the raster layers pyramid list.
buildPyramids Create pyramid overviews
childEvent
clone
colorInterpretation Returns data type for the band specified by number
colorInterpretationName
colorName
colorTable
connectNotify
copyBaseSettings Copy member variables from other raster data provider.
create Creates a new dataset with mDataSourceURI
customEvent
dataTimestamp Current time stamp of data source
dataType Returns data type for the band specified by number
disconnectNotify
dpi Returns the dpi of the output device.
extent
getLegendGraphicFetcher Returns a new image downloader for the raster legend.
hasPyramids Returns true if raster has at least one populated histogram.
htmlMetadata Returns metadata in a format suitable for feeding directly into a subset of the GUI raster properties “Metadata” tab.
identify Identify raster value(s) found on the point position.
identifyFormatFromName
identifyFormatLabel
identifyFormatName
identifyFormatToCapability
initHistogram
initStatistics
isEditable Checks whether the provider is in editing mode, i.e.
isSignalConnected
lastError Returns the verbose error text for the last error in this provider
lastErrorFormat Returns the format of the error text for the last error in this provider
lastErrorTitle Returns the caption error text for the last error in this provider
providerCapabilities Returns flags containing the supported capabilities of the data provider.
pyramidResamplingMethods Returns a list of pyramid resampling method name and label pairs for given provider
receivers
reload Reload data (data could change)
remove Remove dataset
sample Samples a raster value from the specified band found at the point position.
sender
senderSignalIndex
setDpi Sets the output device resolution.
setEditable Turns on/off editing mode of the provider.
setError
setInput It makes no sense to set input on provider */
setNoDataValue Set no data value on created dataset
setUseSourceNoDataValue Sets the source nodata value usage
setUserNoDataValue
sourceDataType Returns source data type for the band specified by number, source data type may be shorter than dataType
sourceHasNoDataValue Returns true if source band has no data value
sourceNoDataValue Value representing no data value.
stepHeight Step height for raster iterations.
stepWidth Step width for raster iterations.
subLayers Returns the sublayers of this layer - useful for providers that manage their own layers, such as WMS *
supportsLegendGraphic Returns whether the provider supplies a legend graphic
timerEvent
timestamp Time stamp of data source in the moment when data/metadata were loaded by provider
useSourceNoDataValue Returns the source nodata value usage
userNoDataValues Returns a list of user no data value ranges.
userNoDataValuesContains Returns true if user no data contains value
validateCreationOptions Validates creation options for a specific dataset and destination format.
validatePyramidsConfigOptions Validates pyramid creation options for a specific dataset and destination format
write
writeBlock Writes pixel data from a raster block into the provider data source.

Signals

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

Attributes

NoProviderCapabilities
ReadLayerMetadata
WriteLayerMetadata
NoProviderCapabilities = 0
class ProviderCapabilities

Bases: sip.wrapper

QgsRasterDataProvider.ProviderCapabilities(Union[QgsRasterDataProvider.ProviderCapabilities, QgsRasterDataProvider.ProviderCapability]) QgsRasterDataProvider.ProviderCapabilities(QgsRasterDataProvider.ProviderCapabilities)

class ProviderCapability

Bases: int

ReadLayerMetadata = 2
WriteLayerMetadata = 4
appendError()
bandOffset(self, bandNo: int) → float

Read band offset for raster value

New in version 2.3.

bandScale(self, bandNo: int) → float

Read band scale for raster value

New in version 2.3.

block(self, bandNo: int, boundingBox: QgsRectangle, width: int, height: int, feedback: QgsRasterBlockFeedback = None) → QgsRasterBlock

Read block of data using given extent and size.

buildPyramidList(self, overviewList: Iterable[int] = []) → List[QgsRasterPyramid]

Returns the raster layers pyramid list.

Parameters:overviewList – used to construct the pyramid list (optional), when empty the list is defined by the provider. A pyramid list defines the POTENTIAL pyramids that can be in a raster. To know which of the pyramid layers ACTUALLY exists you need to look at the existsFlag member in each struct stored in the list.
buildPyramids(self, pyramidList: object, resamplingMethod: str = '', format: QgsRaster.RasterPyramidsFormat = QgsRaster.PyramidsGTiff, configOptions: Iterable[str] = [], feedback: QgsRasterBlockFeedback = None) → str

Create pyramid overviews

childEvent()
clone(self) → QgsRasterInterface
colorInterpretation(self, bandNo: int) → int

Returns data type for the band specified by number

colorInterpretationName(self, bandNo: int) → str
colorName(self, colorInterpretation: int) → str
colorTable(self, bandNo: int) → List[QgsColorRampShader.ColorRampItem]
connectNotify()
copyBaseSettings(self, other: QgsRasterDataProvider)

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

create(providerKey: str, uri: str, format: str, nBands: int, type: Qgis.DataType, width: int, height: int, crs: QgsCoordinateReferenceSystem, createOptions: Iterable[str] = []) → Tuple[QgsRasterDataProvider, float]

Creates a new dataset with mDataSourceURI

customEvent()
dataTimestamp(self) → QDateTime

Current time stamp of data source

dataType(self, bandNo: int) → Qgis.DataType

Returns data type for the band specified by number

disconnectNotify()
dpi(self) → int

Returns the dpi of the output device.

extent(self) → QgsRectangle
getLegendGraphicFetcher(self, mapSettings: QgsMapSettings) → QgsImageFetcher

Returns a new image downloader for the raster legend.

Parameters:mapSettings – map settings for legend providers supporting contextual legends.
Returns:a download handler or null if the provider does not support legend at all. Ownership of the returned object is transferred to caller.

New in version 2.8.

hasPyramids(self) → bool

Returns true if raster has at least one populated histogram.

htmlMetadata(self) → str

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

identify(self, point: QgsPointXY, format: QgsRaster.IdentifyFormat, boundingBox: QgsRectangle = QgsRectangle(), width: int = 0, height: int = 0, dpi: int = 96) → QgsRasterIdentifyResult

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

Parameters:
  • point – coordinates in data source CRS
  • format – result format
  • boundingBox – context bounding box
  • width – context width
  • height – context height
  • dpi – context dpi
Returns:

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

Note

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

See also

sample()

identifyFormatFromName(formatName: str) → QgsRaster.IdentifyFormat
identifyFormatLabel(format: QgsRaster.IdentifyFormat) → str
identifyFormatName(format: QgsRaster.IdentifyFormat) → str
identifyFormatToCapability(format: QgsRaster.IdentifyFormat) → QgsRasterInterface.Capability
initHistogram()
initStatistics()
isEditable(self) → bool

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()

New in version 3.0.

isSignalConnected()
lastError(self) → str

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(self) → str

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

lastErrorTitle(self) → str

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(self) → QgsRasterDataProvider.ProviderCapabilities

Returns flags containing the supported capabilities of the data provider.

New in version 3.0.

pyramidResamplingMethods(providerKey: str) → List[Tuple[str, str]]

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

receivers()
reload(self) → bool

Reload data (data could change)

remove(self) → bool

Remove dataset

sample(self, point: QgsPointXY, band: int, boundingBox: QgsRectangle = QgsRectangle(), width: int = 0, height: int = 0, dpi: int = 96) → Tuple[float, bool]

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()

New in version 3.4.

sender()
senderSignalIndex()
setDpi(self, dpi: int)

Sets the output device resolution.

setEditable(self, enabled: bool) → bool

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()

New in version 3.0.

setError()
setInput(self, input: QgsRasterInterface) → bool

It makes no sense to set input on provider */

setNoDataValue(self, bandNo: int, noDataValue: float) → bool

Set no data value on created dataset

Parameters:
  • bandNo – band number
  • noDataValue – no data value
setUseSourceNoDataValue(self, bandNo: int, use: bool)

Sets the source nodata value usage

setUserNoDataValue(self, bandNo: int, noData: object)
sourceDataType(self, bandNo: int) → Qgis.DataType

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

sourceHasNoDataValue(self, bandNo: int) → bool

Returns true if source band has no data value

sourceNoDataValue(self, bandNo: int) → float

Value representing no data value.

statusChanged

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

New in version 2.14: [signal]

stepHeight(self) → int

Step height for raster iterations.

See also

stepWidth()

New in version 3.0.

stepWidth(self) → int

Step width for raster iterations.

See also

stepHeight()

New in version 3.0.

subLayers(self) → List[str]

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

supportsLegendGraphic(self) → bool

Returns whether the provider supplies a legend graphic

timerEvent()
timestamp(self) → QDateTime

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

useSourceNoDataValue(self, bandNo: int) → bool

Returns the source nodata value usage

userNoDataValues(self, bandNo: int) → object

Returns a list of user no data value ranges.

userNoDataValuesContains(self, bandNo: int, value: float) → bool

Returns true if user no data contains value

validateCreationOptions(self, createOptions: Iterable[str], format: str) → str

Validates creation options for a specific dataset and destination format.

Note

used by GDAL provider only

Note

see also validateCreationOptionsFormat() in gdal provider for validating options based on format only

validatePyramidsConfigOptions(self, pyramidsFormat: QgsRaster.RasterPyramidsFormat, configOptions: Iterable[str], fileFormat: str) → str

Validates pyramid creation options for a specific dataset and destination format

Note

used by GDAL provider only

write(self, data: sip.voidptr, band: int, width: int, height: int, xOffset: int, yOffset: int) → bool
writeBlock(self, block: QgsRasterBlock, band: int, xOffset: int = 0, yOffset: int = 0) → bool

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()

Returns:true on success

New in version 3.0.