Class: QgsRasterLayer¶

Represents a raster layer.

A QgsRasterLayer is instantiated by specifying the name of a data provider, such as “gdal” or “wms”, and a url defining the specific data set to connect to. The raster layer constructor in turn instantiates a QgsRasterDataProvider subclass corresponding to the provider type, and passes it the url. The data provider connects to the data source.

Sample usage of the QgsRasterLayer class:

my_raster_layer = QgsRasterLayer("/path/to/file.tif", "my layer")

Class Hierarchy¶

Base classes¶

`QgsMapLayer`	Base class for all map layer types.
QObject
`QgsAbstractProfileSource`	Interface for classes which can generate elevation profiles.

Enums

LayerType

alias of RasterLayerType

Abstract Methods

clone

Returns a new instance equivalent to this one.

Methods

`as_numpy`	Returns the layer data as a numpy array.
`attributeTable`	Returns the (possibly NULL) raster attribute table for the given band bandNumber.
`attributeTableCount`	Returns the number of attribute tables for the raster by counting the number of bands that have an associated attribute table.
`bandCount`	Returns the number of bands in this layer.
`bandName`	Returns the name of a band given its number.
`brightnessFilter`	Returns the raster's brightness/contrast filter.
`canCreateRasterAttributeTable`	Returns `True` if the raster renderer is suitable for creation of a raster attribute table.
`constDataProvider`	Returns the source data provider.
`draw`	This is an overloaded version of the `draw()` function that is called by both `draw()` and thumbnailAsPixmap
`height`	Returns the height of the (unclipped) raster.
`hueSaturationFilter`	Returns the raster's hue/saturation filter.
`ignoreExtents`	If the ignoreExtent flag is set, the layer will also render outside the bounding box reported by the data provider.
`labeling`	Access to labeling configuration.
`labelsEnabled`	Returns whether the layer contains labels which are enabled and should be drawn.
`legendSymbologyItems`	Returns a list with classification items (Text and color).
`paletteAsPixmap`	Returns a 100x100 pixmap of the color palette.
`pipe`	Returns the raster pipe.
`previewAsImage`	Draws a preview of the rasterlayer into a QImage
`rasterType`	Returns the raster layer type (which is a read only property).
`rasterUnitsPerPixelX`	Returns the number of raster units per each raster pixel in X axis.
`rasterUnitsPerPixelY`	Returns the number of raster units per each raster pixel in Y axis.
`renderer`	Returns the raster's renderer.
`resampleFilter`	Returns the raster's resample filter.
`resamplingStage`	Returns which stage of the pipe should apply resampling.
`setContrastEnhancement`	Set contrast enhancement algorithm
`setDataProvider`	Set the data provider.
`setDefaultContrastEnhancement`	Sets the default contrast enhancement
`setLabeling`	Sets labeling configuration.
`setLabelsEnabled`	Sets whether labels should be enabled for the layer.
`setRenderer`	Sets the raster's renderer.
`setResamplingStage`	Select which stage of the pipe should apply resampling.
`showStatusMessage`
`width`	Returns the width of the (unclipped) raster.
`writeSld`	Writes the symbology of the layer into the document provided in SLD 1.0.0 format

Virtual Methods

In PyQGIS, only methods marked as virtual can be safely overridden in a Python subclass of QgsRasterLayer. See the FAQ for more details.

`dataProvider`	Returns the source data provider.
`setSubsetString`	Sets the string (typically sql) used to define a subset of the layer
`subsetString`	Returns the string (typically sql) used to define a subset of the layer.

Static Methods

`isValidRasterFileName`	This helper checks to see whether the file name appears to be a valid raster file name.
`lastModified`	Returns time stamp for given file name

Signals

subsetStringChanged

Emitted when the layer's subset string has changed.

Attributes

`MULTIPLE_BAND_MULTI_BYTE_ENHANCEMENT_ALGORITHM`	Default enhancement algorithm for multiple band raster of type different from Byte
`MULTIPLE_BAND_SINGLE_BYTE_ENHANCEMENT_ALGORITHM`	Default enhancement algorithm for multiple band raster of type Byte
`SAMPLE_SIZE`	Default sample size (number of pixels) for estimated statistics/histogram calculation
`SINGLE_BAND_ENHANCEMENT_ALGORITHM`	Default enhancement algorithm for single band raster

class qgis.core.QgsRasterLayer[source]¶

Bases: QgsMapLayer, QgsAbstractProfileSource

__init__(): Constructor. Provider is not set.

__init__(uri: str | None, baseName: str | None = '', providerType: str | None = '', options: QgsRasterLayer.LayerOptions = QgsRasterLayer.LayerOptions())

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.

Parameters:

uri (Optional[str])
baseName (Optional[str] = '')
providerType (Optional[str] = '')
options (QgsRasterLayer.LayerOptions = QgsRasterLayer.LayerOptions())

class LayerOptions¶

Bases: object

Setting options for loading raster layers.

skipCrsValidation: bool¶

Controls whether the layer is allowed to have an invalid/unknown CRS.

If True, then no validation will be performed on the layer’s CRS and the layer layer’s crs() may be invalid() (i.e. the layer will have no georeferencing available and will be treated as having purely numerical coordinates).

If False (the default), the layer’s CRS will be validated using QgsCoordinateReferenceSystem.validate(), which may cause a blocking, user-facing dialog asking users to manually select the correct CRS for the layer.

Added in version 3.10.

LayerType¶: alias of RasterLayerType

MULTIPLE_BAND_MULTI_BYTE_ENHANCEMENT_ALGORITHM: ContrastEnhancementAlgorithm = 1¶: Default enhancement algorithm for multiple band raster of type different from Byte

MULTIPLE_BAND_SINGLE_BYTE_ENHANCEMENT_ALGORITHM: ContrastEnhancementAlgorithm = 0¶: Default enhancement algorithm for multiple band raster of type Byte

SAMPLE_SIZE: float = 250000.0¶: Default sample size (number of pixels) for estimated statistics/histogram calculation

SINGLE_BAND_ENHANCEMENT_ALGORITHM: ContrastEnhancementAlgorithm = 1¶: Default enhancement algorithm for single band raster

as_numpy(use_masking=True, bands: List[int] | None = None) → List[ndarray | MaskedArray]¶

Returns the layer data as a numpy array.

If use_masking is True then the returned arrays will be numpy masked arrays, masking the raster block’s nodata values.

If bands is provided, only the specified bands will be included in the returned array; otherwise, all bands will be used.

Raises:: QgsNotSupportedException – if numpy is not available on the system

Added in version 3.40.

attributeTable(self, bandNumber: int) → QgsRasterAttributeTable | None[source]¶

Returns the (possibly NULL) raster attribute table for the given band bandNumber.

Added in version 3.30.

Parameters:: bandNumber (int)
Return type:: Optional[QgsRasterAttributeTable]

attributeTableCount(self) → int[source]¶

Returns the number of attribute tables for the raster by counting the number of bands that have an associated attribute table.

Added in version 3.30.

Return type:: int

bandCount(self) → int[source]¶

Returns the number of bands in this layer.

Return type:: int

bandName(self, bandNoInt: int) → str[source]¶

Returns the name of a band given its number.

Parameters:: bandNoInt (int)
Return type:: str

brightnessFilter(self) → QgsBrightnessContrastFilter | None[source]¶

Returns the raster’s brightness/contrast filter.

See also

resampleFilter()

See also

hueSaturationFilter()

Return type:: Optional[QgsBrightnessContrastFilter]

canCreateRasterAttributeTable(self) → bool[source]¶

Returns True if the raster renderer is suitable for creation of a raster attribute table. The supported renderers are QgsPalettedRasterRenderer and QgsSingleBandPseudoColorRenderer.

Added in version 3.30.

Return type:: bool

abstract clone(self) → QgsRasterLayer | None[source]¶

Returns a new instance equivalent to this one. A new provider is created for the same data source and renderer is cloned too.

Return type:: Optional[QgsRasterLayer]
Returns:: a new layer instance

constDataProvider(self) → QgsRasterDataProvider | None¶

Returns the source data provider.

This will be None if the layer is invalid.

Return type:: Optional[QgsRasterDataProvider]

virtual dataProvider(self) → QgsRasterDataProvider | None[source]¶

Returns the source data provider.

This will be None if the layer is invalid.

Return type:: Optional[QgsRasterDataProvider]

draw(self, theQPainter: QPainter | None, myRasterViewPort: QgsRasterViewPort | None, qgsMapToPixel: QgsMapToPixel | None = None)[source]¶

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

Parameters:

theQPainter (Optional[QPainter])
myRasterViewPort (Optional[QgsRasterViewPort])
qgsMapToPixel (Optional[QgsMapToPixel] = None)

height(self) → int[source]¶

Returns the height of the (unclipped) raster.

See also

width()

Return type:: int

hueSaturationFilter(self) → QgsHueSaturationFilter | None[source]¶

Returns the raster’s hue/saturation filter.

See also

resampleFilter()

See also

brightnessFilter()

Return type:: Optional[QgsHueSaturationFilter]

ignoreExtents(self) → bool[source]¶

If the ignoreExtent flag is set, the layer will also render outside the bounding box reported by the data provider. To be used for example for WMS layers with labels or symbology that happens to be drawn outside the data extent.

Added in version 3.10.

Return type:: bool

static isValidRasterFileName(fileNameQString: str | None, retError: str | None) → bool[source]¶

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.

Parameters:

fileNameQString (Optional[str])
retError (Optional[str])

Return type:

bool

static isValidRasterFileName(fileNameQString: str | None) → bool[source]

Parameters:: fileNameQString (Optional[str])
Return type:: bool

labeling(self) → QgsAbstractRasterLayerLabeling | None[source]¶

Access to labeling configuration. May be None if labeling is not used.

Note

Labels will only be rendered if labelsEnabled() returns True.

See also

labelsEnabled()

See also

setLabeling()

Added in version 3.42.

Return type:: Optional[QgsAbstractRasterLayerLabeling]

labelsEnabled(self) → bool[source]¶

Returns whether the layer contains labels which are enabled and should be drawn.

Return type:: bool
Returns:: True if layer contains enabled labels

See also

setLabelsEnabled()

See also

labeling()

Added in version 3.42.

static lastModified(name: str | None) → QDateTime[source]¶

Returns time stamp for given file name

Parameters:: name (Optional[str])
Return type:: QDateTime

legendSymbologyItems(self) → List[Tuple[str, QColor]][source]¶

Returns a list with classification items (Text and color).

Deprecated since version 3.40: Use QgsRasterRenderer.createLegendNodes() instead.

Return type:: List[Tuple[str, QColor]]

paletteAsPixmap(self, bandNumber: int = 1) → QPixmap[source]¶

Returns a 100x100 pixmap of the color palette. If the layer has no palette a white pixmap will be returned

Parameters:: bandNumber (int = 1) – the number of the band to use for generating a pixmap of the associated palette
Return type:: QPixmap

pipe(self) → QgsRasterPipe | None[source]¶

Returns the raster pipe.

Return type:: Optional[QgsRasterPipe]

previewAsImage(self, size: QSize, bgColor: QColor | Qt.GlobalColor = Qt.white, format: QImage.Format = QImage.Format_ARGB32_Premultiplied) → QImage[source]¶

Draws a preview of the rasterlayer into a QImage

Parameters:

size (QSize)
bgColor (Union[QColor, Qt.GlobalColor] = Qt.white)
format (QImage.Format = QImage.Format_ARGB32_Premultiplied)

Return type:

QImage

rasterType(self) → Qgis.RasterLayerType[source]¶

Returns the raster layer type (which is a read only property).

Return type:: Qgis.RasterLayerType

rasterUnitsPerPixelX(self) → float[source]¶

Returns the number of raster units per each raster pixel in X axis.

In a world file, this is normally the first row (without the sign). (E.g. the value reported by the GDAL geotransform[1]).

Note

If the dataProvider() does not have native size/resolution then 1 will be returned. QgsRasterDataProvider.capabilities() can be used to test for the Qgis.RasterInterfaceCapability.Size capability in order to determine whether the data provider has a native size/resolution.

See also

rasterUnitsPerPixelY()

Return type:: float

rasterUnitsPerPixelY(self) → float[source]¶

Returns the number of raster units per each raster pixel in Y axis.

In a world file, this is normally the first row (without the sign).

Note

If the dataProvider() does not have native size/resolution then 1 will be returned. QgsRasterDataProvider.capabilities() can be used to test for the Qgis.RasterInterfaceCapability.Size capability in order to determine whether the data provider has a native size/resolution.

See also

rasterUnitsPerPixelX()

Return type:: float

renderer(self) → QgsRasterRenderer | None[source]¶

Returns the raster’s renderer.

See also

setRenderer()

Return type:: Optional[QgsRasterRenderer]

resampleFilter(self) → QgsRasterResampleFilter | None[source]¶

Returns the raster’s resample filter.

See also

brightnessFilter()

See also

hueSaturationFilter()

Return type:: Optional[QgsRasterResampleFilter]

resamplingStage(self) → Qgis.RasterResamplingStage[source]¶

Returns which stage of the pipe should apply resampling.

See also

QgsRasterPipe.resamplingStage()

Added in version 3.16.

Return type:: Qgis.RasterResamplingStage

setContrastEnhancement(self, algorithm: QgsContrastEnhancement.ContrastEnhancementAlgorithm, limits: Qgis.RasterRangeLimit = Qgis.RasterRangeLimit.MinimumMaximum, extent: QgsRectangle = QgsRectangle(), sampleSize: int = QgsRasterLayer.SAMPLE_SIZE, generateLookupTableFlag: bool = True)[source]¶

Set contrast enhancement algorithm

Parameters:

algorithm (QgsContrastEnhancement.ContrastEnhancementAlgorithm) – Contrast enhancement algorithm
limits (Qgis.RasterRangeLimit = Qgis.RasterRangeLimit.MinimumMaximum) – Limits
extent (QgsRectangle = QgsRectangle()) – Extent used to calculate limits, if empty, use full layer extent
sampleSize (int = QgsRasterLayer.SAMPLE_SIZE) – Size of data sample to calculate limits, if 0, use full resolution
generateLookupTableFlag (bool = True) – Generate lookup table.

setDataProvider(self, provider: str | None)[source]¶

Set the data provider.

Deprecated since version 3.40: Use the version with ProviderOptions instead.

Parameters:: provider (Optional[str])

setDataProvider(self, provider: str | None, options: QgsDataProvider.ProviderOptions, flags: Qgis.DataProviderReadFlags | Qgis.DataProviderReadFlag = Qgis.DataProviderReadFlags())[source]

Set the data provider.

Parameters:

provider (Optional[str]) – provider key string, must match a valid QgsRasterDataProvider key. E.g. “gdal”, “wms”, etc.
options (QgsDataProvider.ProviderOptions) – provider options
flags (Union[Qgis.DataProviderReadFlags, Qgis.DataProviderReadFlag] = Qgis.DataProviderReadFlags()) – provider flags since QGIS 3.16

Added in version 3.2.

setDefaultContrastEnhancement(self)[source]¶: Sets the default contrast enhancement

setLabeling(self, labeling: QgsAbstractRasterLayerLabeling | None)[source]¶

Sets labeling configuration. Takes ownership of the object.

See also

labeling()

Added in version 3.42.

Parameters:: labeling (Optional[QgsAbstractRasterLayerLabeling])

setLabelsEnabled(self, enabled: bool)[source]¶

Sets whether labels should be enabled for the layer.

Note

Labels will only be rendered if labelsEnabled() is True and a labeling object is returned by labeling().

See also

labelsEnabled()

See also

labeling()

Added in version 3.42.

Parameters:: enabled (bool)

setRenderer(self, renderer: QgsRasterRenderer | None)[source]¶

Sets the raster’s renderer. Takes ownership of the renderer object.

See also

renderer()

Parameters:: renderer (Optional[QgsRasterRenderer])

setResamplingStage(self, stage: Qgis.RasterResamplingStage)[source]¶

Select which stage of the pipe should apply resampling.

See also

QgsRasterPipe.setResamplingStage()

Added in version 3.16.

Parameters:: stage (Qgis.RasterResamplingStage)

virtual setSubsetString(self, subset: str | None) → bool[source]¶

Sets the string (typically sql) used to define a subset of the layer

Parameters:: subset (Optional[str]) – The subset string. This may be the where clause of a sql statement or other definition string specific to the underlying dataprovider and data store.
Return type:: bool
Returns:: True, when setting the subset string was successful, False otherwise

Added in version 3.12.

showStatusMessage(self, message: str | None)[source]¶

Parameters:: message (Optional[str])

virtual subsetString(self) → str[source]¶

Returns the string (typically sql) used to define a subset of the layer.

Return type:: str
Returns:: The subset string or an empty string if not implemented by the provider

Added in version 3.12.

signal subsetStringChanged[source]¶: Emitted when the layer’s subset string has changed.

Added in version 3.12.

width(self) → int[source]¶

Returns the width of the (unclipped) raster.

See also

height()

Return type:: int

writeSld(self, node: QDomNode, doc: QDomDocument, errorMessage: str | None, props: Dict[str, Any] = {}) → bool[source]¶

Writes the symbology of the layer into the document provided in SLD 1.0.0 format

Parameters:

node (QDomNode) – the node that will have the style element added to it.
doc (QDomDocument) – the document that will have the QDomNode added.
errorMessage (Optional[str]) – reference to string that will be updated with any error messages
props (Dict[str, Any] = {}) – a open ended set of properties that can drive/inform the SLD encoding

Return type:

bool

Returns:

True in case of success

Deprecated since version 3.44: Use the version with QgsSldExportContext instead.

writeSld(self, node: QDomNode, doc: QDomDocument, context: QgsSldExportContext) → bool[source]

Writes the symbology of the layer into the document provided in SLD 1.1 format

Parameters:

node (QDomNode) – the node that will have the style element added to it.
doc (QDomDocument) – the document that will have the QDomNode added.
context (QgsSldExportContext) – export context. Errors and warnings may be retrieved from this context.

Return type:

bool

Returns:

True in case of success

Added in version 3.44.