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.
Enums
Methods
Read band offset for raster value
Read band scale for raster value
Read block of data using given extent and size.
Returns the raster layers pyramid list.
Create pyramid overviews
Returns data type for the band specified by number
Copy member variables from other raster data provider.
Creates a new dataset with mDataSourceURI
Current time stamp of data source
Returns data type for the band specified by number
Returns the dpi of the output device.
Returns a new image downloader for the raster legend.
Returns true if raster has at least one populated histogram.
Returns metadata in a format suitable for feeding directly into a subset of the GUI raster properties “Metadata” tab.
Identify raster value(s) found on the point position.
Checks whether the provider is in editing mode, i.e.
Returns the verbose error text for the last error in this provider
Returns the format of the error text for the last error in this provider
Returns the caption error text for the last error in this provider
Returns flags containing the supported capabilities of the data provider.
Returns a list of pyramid resampling method name and label pairs for given provider
Reload data (data could change)
Remove dataset
Samples a raster value from the specified
band
found at thepoint
position.Sets the output device resolution.
Turns on/off editing mode of the provider.
It makes no sense to set input on provider */
Set no data value on created dataset
Sets the source nodata value usage
Returns source data type for the band specified by number, source data type may be shorter than dataType
Returns true if source band has no data value
Value representing no data value.
Step height for raster iterations.
Step width for raster iterations.
Returns the sublayers of this layer - useful for providers that manage their own layers, such as WMS *
Returns whether the provider supplies a legend graphic
Time stamp of data source in the moment when data/metadata were loaded by provider
Returns the source nodata value usage
Returns a list of user no data value ranges.
Returns true if user no data contains value
Validates creation options for a specific dataset and destination format.
Validates pyramid creation options for a specific dataset and destination format
Writes pixel data from a raster block into the provider data source.
Signals
Emit a message to be displayed on status bar, usually used by network providers (WMS,WCS)
Attributes
-
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¶
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appendError
()¶
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bandOffset
(self, bandNo: int) → float¶ Read band offset for raster value
New in version 2.3.
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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
()¶
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clone
(self) → QgsRasterInterface¶
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colorInterpretation
(self, bandNo: int) → int¶ Returns data type for the band specified by number
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colorInterpretationName
(self, bandNo: int) → str¶
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colorName
(self, colorInterpretation: int) → str¶
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colorTable
(self, bandNo: int) → List[QgsColorRampShader.ColorRampItem]¶
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connectNotify
()¶
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copyBaseSettings
(self, other: QgsRasterDataProvider)¶ Copy member variables from other raster data provider. Useful for implementation of clone() method in subclasses
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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
()¶
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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¶
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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.
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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
-
identifyFormatFromName
(formatName: str) → QgsRaster.IdentifyFormat¶
-
identifyFormatLabel
(format: QgsRaster.IdentifyFormat) → str¶
-
identifyFormatName
(format: QgsRaster.IdentifyFormat) → str¶
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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
New in version 3.0.
-
isSignalConnected
()¶
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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
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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 thepoint
position. The context parametersboundingBox
,width
andheight
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, thenok
will be set to false. In this case the function will return a NaN value.See also
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
New in version 3.0.
-
setError
()¶
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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)¶
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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
New in version 3.0.
-
stepWidth
(self) → int¶ Step width for raster iterations.
See also
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
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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
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write
(self, data: sip.voidptr, band: int, width: int, height: int, xOffset: int, yOffset: int) → bool¶
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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
- Returns
true on success
New in version 3.0.
-