Class: QgsRasterDataProvider

class qgis.core.QgsRasterDataProvider

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

QgsRasterDataProvider(uri: str, providerOptions: 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.

Enums

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 None 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.