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.

class qgis.core.QgsRasterLayer

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

LayerType

alias of RasterLayerType

MULTIPLE_BAND_MULTI_BYTE_ENHANCEMENT_ALGORITHM: ContrastEnhancementAlgorithm = 1

MULTIPLE_BAND_SINGLE_BYTE_ENHANCEMENT_ALGORITHM: ContrastEnhancementAlgorithm = 0

SAMPLE_SIZE: float = 250000.0

SINGLE_BAND_ENHANCEMENT_ALGORITHM: ContrastEnhancementAlgorithm = 1

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

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

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

Returns the number of bands in this layer.

Return type:

int

bandName(self, bandNoInt: int) → str

Returns the name of a band given its number.

Parameters:

bandNoInt (int)

Return type:

str

brightnessFilter(self) → QgsBrightnessContrastFilter | None

Returns the raster’s brightness/contrast filter.

See also

resampleFilter()

See also

hueSaturationFilter()

Return type:

Optional[QgsBrightnessContrastFilter]

canCreateRasterAttributeTable(self) → bool

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

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

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)

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

Returns the height of the (unclipped) raster.

See also

width()

Return type:

int

hueSaturationFilter(self) → QgsHueSaturationFilter | None

Returns the raster’s hue/saturation filter.

See also

resampleFilter()

See also

brightnessFilter()

Return type:

Optional[QgsHueSaturationFilter]

ignoreExtents(self) → bool

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

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.

isValidRasterFileName(fileNameQString: Optional[str]) -> bool

Parameters:

• fileNameQString (Optional[str])

• retError (Optional[str])

Return type:

bool

labeling(self) → QgsAbstractRasterLayerLabeling | None

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

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

Returns time stamp for given file name

Parameters:

name (Optional[str])

Return type:

QDateTime

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

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

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

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

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

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

Return type:

Qgis.RasterLayerType

rasterUnitsPerPixelX(self) → float

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

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

Returns the raster’s renderer.

See also

setRenderer()

Return type:

Optional[QgsRasterRenderer]

resampleFilter(self) → QgsRasterResampleFilter | None

Returns the raster’s resample filter.

See also

brightnessFilter()

See also

hueSaturationFilter()

Return type:

Optional[QgsRasterResampleFilter]

resamplingStage(self) → Qgis.RasterResamplingStage

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)

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)

Set the data provider.

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

setDataProvider(self, provider: Optional[str], options: QgsDataProvider.ProviderOptions, flags: Union[Qgis.DataProviderReadFlags, Qgis.DataProviderReadFlag] = Qgis.DataProviderReadFlags()) Set the data provider.

Parameters:

• provider (Optional[str]) – provider key string, must match a valid QgsRasterDataProvider key. E.g. “gdal”, “wms”, etc.

• options – provider options

• flags – provider flags since QGIS 3.16

Added in version 3.2.

setDefaultContrastEnhancement(self)

Sets the default contrast enhancement

setLabeling(self, labeling: QgsAbstractRasterLayerLabeling | None)

Sets labeling configuration. Takes ownership of the object.

See also

labeling()

Added in version 3.42.

Parameters:

labeling (Optional[QgsAbstractRasterLayerLabeling])

setLabelsEnabled(self, enabled: bool)

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)

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

See also

renderer()

Parameters:

renderer (Optional[QgsRasterRenderer])

setResamplingStage(self, stage: Qgis.RasterResamplingStage)

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

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)

Parameters:

message (Optional[str])

virtual subsetString(self) → str

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

pyqtSignal(*types, name: str = …, revision: int = …, arguments: Sequence = …) -> PYQT_SIGNAL

types is normally a sequence of individual types. Each type is either a type object or a string that is the name of a C++ type. Alternatively each type could itself be a sequence of types each describing a different overloaded signal. name is the optional C++ name of the signal. If it is not specified then the name of the class attribute that is bound to the signal is used. revision is the optional revision of the signal that is exported to QML. If it is not specified then 0 is used. arguments is the optional sequence of the names of the signal’s arguments.

width(self) → int

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

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

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

Parameters:

• node – the node that will have the style element added to it.

• doc – the document that will have the QDomNode added.

• context – 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.