Utilities for working with GDAL. More...

#include <qgsgdalutils.h>

Classes
struct	VsiNetworkFileSystemDetails
	Encapsulates details for a GDAL VSI network file system. More...

Static Public Member Functions
static bool	applyVsiCredentialOptions (const QString &prefix, const QString &path, const QVariantMap &options)
	Attempts to apply VSI credential options.

static gdal::dataset_unique_ptr	blockToSingleBandMemoryDataset (const QgsRectangle &extent, QgsRasterBlock *block)
	Converts a raster block to a single band GDAL memory dataset.

static gdal::dataset_unique_ptr	blockToSingleBandMemoryDataset (double rotation, const QgsPointXY &origin, double gridXSize, double gridYSize, QgsRasterBlock *block)
	Converts a raster block to a single band GDAL memory dataset with rotation angle,side sizes of the grid, origin if the grid (top left if rotation == 0)

static gdal::dataset_unique_ptr	blockToSingleBandMemoryDataset (int pixelWidth, int pixelHeight, const QgsRectangle &extent, void *block, GDALDataType dataType)
	Converts a data block to a single band GDAL memory dataset.

static gdal::dataset_unique_ptr	createMultiBandMemoryDataset (GDALDataType dataType, int bands, const QgsRectangle &extent, int width, int height, const QgsCoordinateReferenceSystem &crs)
	Creates a new multi band memory dataset with given parameters.

static gdal::dataset_unique_ptr	createSingleBandMemoryDataset (GDALDataType dataType, const QgsRectangle &extent, int width, int height, const QgsCoordinateReferenceSystem &crs)
	Creates a new single band memory dataset with given parameters.

static gdal::dataset_unique_ptr	createSingleBandTiffDataset (const QString &filename, GDALDataType dataType, const QgsRectangle &extent, int width, int height, const QgsCoordinateReferenceSystem &crs)
	Creates a new single band TIFF dataset with given parameters.

static GDALDataType	gdalDataTypeFromQgisDataType (Qgis::DataType dataType)
	Returns the GDAL data type corresponding to the QGIS data type dataType.

static QString	gdalDocumentationUrlForDriver (GDALDriverH hDriver)
	Returns the URL for the GDAL documentation for the specified driver.

static GDALResampleAlg	gdalResamplingAlgorithm (Qgis::RasterResamplingMethod method)
	Returns the GDAL resampling method corresponding to the QGIS resampling method.

static QString	helpCreationOptionsFormat (const QString &format)
	Gets creation options metadata for a given format.

static gdal::dataset_unique_ptr	imageToMemoryDataset (const QImage &image)
	Converts an image to a GDAL memory dataset by borrowing image data.

static bool	isVsiArchiveFileExtension (const QString &extension)
	Returns `true` if a file extension is a supported archive style container (e.g.

static bool	isVsiArchivePrefix (const QString &prefix)
	Returns `true` if prefix is a supported archive style container prefix (e.g.

static QStringList	multiLayerFileExtensions ()
	Returns a list of file extensions which potentially contain multiple layers representing GDAL raster or vector layers.

static char **	papszFromStringList (const QStringList &list)
	Helper function.

static bool	pathIsCheapToOpen (const QString &path, int smallFileSizeLimit=50000)
	Returns `true` if the dataset at the specified path is considered "cheap" to open.

static QImage	resampleImage (const QImage &image, QSize outputSize, GDALRIOResampleAlg resampleAlg)
	Resamples a QImage image using GDAL resampler.

static bool	resampleSingleBandRaster (GDALDatasetH hSrcDS, GDALDatasetH hDstDS, GDALResampleAlg resampleAlg, const char *pszCoordinateOperation)
	Resamples a single band raster to the destination dataset with different resolution (and possibly with different CRS).

static bool	resampleSingleBandRaster (GDALDatasetH hSrcDS, GDALDatasetH hDstDS, GDALResampleAlg resampleAlg, const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs)
	Resamples a single band raster to the destination dataset with different resolution and different CRS.

static GDALDatasetH	rpcAwareAutoCreateWarpedVrt (GDALDatasetH hSrcDS, const char pszSrcWKT, const char pszDstWKT, GDALResampleAlg eResampleAlg, double dfMaxError, const GDALWarpOptions *psOptionsIn)
	This is a copy of GDALAutoCreateWarpedVRT optimized for imagery using RPC georeferencing that also sets RPC_HEIGHT in GDALCreateGenImgProjTransformer2 based on HEIGHT_OFF.

static void *	rpcAwareCreateTransformer (GDALDatasetH hSrcDS, GDALDatasetH hDstDS=nullptr, char **papszOptions=nullptr)
	This is a wrapper around GDALCreateGenImgProjTransformer2() that takes into account RPC georeferencing (it sets RPC_HEIGHT in GDALCreateGenImgProjTransformer2 based on HEIGHT_OFF).

static void	setupProxy ()
	Sets the gdal proxy variables.

static bool	supportsRasterCreate (GDALDriverH driver)
	Reads whether a driver supports GDALCreate() for raster purposes.

static QString	validateCreationOptionsFormat (const QStringList &createOptions, const QString &format)
	Validates creation options for a given format, regardless of layer.

static bool	vrtMatchesLayerType (const QString &vrtPath, Qgis::LayerType type)
	Returns `true` if the VRT file at the specified path is a VRT matching the given layer type.

static QStringList	vsiArchiveFileExtensions ()
	Returns a list of file extensions which correspond to archive style containers supported by GDAL (e.g.

static QStringList	vsiArchivePrefixes ()
	Returns a list of vsi prefixes which correspond to archive style containers (eg vsizip).

static Qgis::VsiHandlerType	vsiHandlerType (const QString &prefix)
	Returns the VSI handler type for a given VSI prefix.

static QList< VsiNetworkFileSystemDetails >	vsiNetworkFileSystems ()
	Returns a list of available GDAL VSI network file systems.

static QString	vsiPrefixForPath (const QString &path)
	Returns a the vsi prefix which corresponds to a file path, or an empty string if the path is not associated with a vsi prefix.

Friends
class	TestQgsGdalUtils

Detailed Description

Utilities for working with GDAL.

Note: not available in Python bindings

Since: QGIS 3.4

Definition at line 100 of file qgsgdalutils.h.

Member Function Documentation

◆ applyVsiCredentialOptions()

bool QgsGdalUtils::applyVsiCredentialOptions	(	const QString &	prefix,
		const QString &	path,
		const QVariantMap &	options
	)

static

Attempts to apply VSI credential options.

This method uses GDAL's VSISetPathSpecificOption, which will overrwrite any existing options for the same VSI prefix and path.

Returns true if the options could be applied.

Since: QGIS 3.40

Definition at line 1064 of file qgsgdalutils.cpp.

◆ blockToSingleBandMemoryDataset() [1/3]

gdal::dataset_unique_ptr QgsGdalUtils::blockToSingleBandMemoryDataset	(	const QgsRectangle &	extent,
		QgsRasterBlock *	block
	)

static

Converts a raster block to a single band GDAL memory dataset.

Warning: The raster block must stay allocated for the lifetime of the returned gdal dataset.

Since: QGIS 3.30

Definition at line 314 of file qgsgdalutils.cpp.

◆ blockToSingleBandMemoryDataset() [2/3]

gdal::dataset_unique_ptr QgsGdalUtils::blockToSingleBandMemoryDataset	(	double	rotation,
		const QgsPointXY &	origin,
		double	gridXSize,
		double	gridYSize,
		QgsRasterBlock *	block
	)

static

Converts a raster block to a single band GDAL memory dataset with rotation angle,side sizes of the grid, origin if the grid (top left if rotation == 0)

Warning: The raster block must stay allocated for the lifetime of the returned gdal dataset.

Since: QGIS 3.30

Definition at line 332 of file qgsgdalutils.cpp.

◆ blockToSingleBandMemoryDataset() [3/3]

gdal::dataset_unique_ptr QgsGdalUtils::blockToSingleBandMemoryDataset	(	int	pixelWidth,
		int	pixelHeight,
		const QgsRectangle &	extent,
		void *	block,
		GDALDataType	dataType
	)

static

Converts a data block to a single band GDAL memory dataset.

Warning: The data block must stay allocated for the lifetime of the returned gdal dataset.

Since: QGIS 3.26

Definition at line 280 of file qgsgdalutils.cpp.

◆ createMultiBandMemoryDataset()

gdal::dataset_unique_ptr QgsGdalUtils::createMultiBandMemoryDataset	(	GDALDataType	dataType,
		int	bands,
		const QgsRectangle &	extent,
		int	width,
		int	height,
		const QgsCoordinateReferenceSystem &	crs
	)

static

Creates a new multi band memory dataset with given parameters.

Since: QGIS 3.12

Definition at line 180 of file qgsgdalutils.cpp.

◆ createSingleBandMemoryDataset()

gdal::dataset_unique_ptr QgsGdalUtils::createSingleBandMemoryDataset	(	GDALDataType	dataType,
		const QgsRectangle &	extent,
		int	width,
		int	height,
		const QgsCoordinateReferenceSystem &	crs
	)

static

Creates a new single band memory dataset with given parameters.

Since: QGIS 3.8

Definition at line 175 of file qgsgdalutils.cpp.

◆ createSingleBandTiffDataset()

gdal::dataset_unique_ptr QgsGdalUtils::createSingleBandTiffDataset	(	const QString &	filename,
		GDALDataType	dataType,
		const QgsRectangle &	extent,
		int	width,
		int	height,
		const QgsCoordinateReferenceSystem &	crs
	)

static

Creates a new single band TIFF dataset with given parameters.

Since: QGIS 3.8

Definition at line 205 of file qgsgdalutils.cpp.

◆ gdalDataTypeFromQgisDataType()

GDALDataType QgsGdalUtils::gdalDataTypeFromQgisDataType ( Qgis::DataType dataType )

static

Returns the GDAL data type corresponding to the QGIS data type dataType.

Since: QGIS 3.30

Definition at line 583 of file qgsgdalutils.cpp.

◆ gdalDocumentationUrlForDriver()

QString QgsGdalUtils::gdalDocumentationUrlForDriver ( GDALDriverH hDriver )

static

Returns the URL for the GDAL documentation for the specified driver.

Since: QGIS 3.40

Definition at line 1053 of file qgsgdalutils.cpp.

◆ gdalResamplingAlgorithm()

GDALResampleAlg QgsGdalUtils::gdalResamplingAlgorithm ( Qgis::RasterResamplingMethod method )

static

Returns the GDAL resampling method corresponding to the QGIS resampling method.

Since: QGIS 3.30

Definition at line 639 of file qgsgdalutils.cpp.

◆ helpCreationOptionsFormat()

QString QgsGdalUtils::helpCreationOptionsFormat ( const QString & format )

static

Gets creation options metadata for a given format.

Since: QGIS 3.10

Definition at line 490 of file qgsgdalutils.cpp.

◆ imageToMemoryDataset()

gdal::dataset_unique_ptr QgsGdalUtils::imageToMemoryDataset ( const QImage & image )

static

Converts an image to a GDAL memory dataset by borrowing image data.

Warning: The image must exist unchanged for the lifetime of the returned gdal dataset!

Since: QGIS 3.12

Definition at line 236 of file qgsgdalutils.cpp.

◆ isVsiArchiveFileExtension()

bool QgsGdalUtils::isVsiArchiveFileExtension ( const QString & extension )

static

Returns true if a file extension is a supported archive style container (e.g.

".zip").

Since: QGIS 3.32

Definition at line 971 of file qgsgdalutils.cpp.

◆ isVsiArchivePrefix()

bool QgsGdalUtils::isVsiArchivePrefix ( const QString & prefix )

static

Returns true if prefix is a supported archive style container prefix (e.g.

"/vsizip/").

Since: QGIS 3.32

Definition at line 946 of file qgsgdalutils.cpp.

◆ multiLayerFileExtensions()

QStringList QgsGdalUtils::multiLayerFileExtensions ( )

static

Returns a list of file extensions which potentially contain multiple layers representing GDAL raster or vector layers.

Since: QGIS 3.22

Definition at line 753 of file qgsgdalutils.cpp.

◆ papszFromStringList()

char ** QgsGdalUtils::papszFromStringList ( const QStringList & list )

static

Helper function.

Since: QGIS 3.10

Definition at line 521 of file qgsgdalutils.cpp.

◆ pathIsCheapToOpen()

bool QgsGdalUtils::pathIsCheapToOpen	(	const QString &	path,
		int	smallFileSizeLimit = `50000`
	)

static

Returns true if the dataset at the specified path is considered "cheap" to open.

Datasets which are considered cheap to open may correspond to very small file sizes, or data types which only require some inexpensive header parsing to open.

One use case for this method is to test whether a remote dataset can be safely opened to resolve the geometry types and other metadata without causing undue network traffic.

The smallFileSizeLimit argument specifies the maximum file size (in bytes) which will be considered as small.

Since: QGIS 3.22

Definition at line 726 of file qgsgdalutils.cpp.

◆ resampleImage()

QImage QgsGdalUtils::resampleImage	(	const QImage &	image,
		QSize	outputSize,
		GDALRIOResampleAlg	resampleAlg
	)

static

Resamples a QImage image using GDAL resampler.

Since: QGIS 3.12

Definition at line 439 of file qgsgdalutils.cpp.

◆ resampleSingleBandRaster() [1/2]

bool QgsGdalUtils::resampleSingleBandRaster	(	GDALDatasetH	hSrcDS,
		GDALDatasetH	hDstDS,
		GDALResampleAlg	resampleAlg,
		const char *	pszCoordinateOperation
	)

static

Resamples a single band raster to the destination dataset with different resolution (and possibly with different CRS).

Ideally the source dataset should cover the whole area or the destination dataset.

In case of different CRS, the parameter pszCoordinateOperation is the Proj coordinate operation string, that can be obtained with QgsCoordinateTransformContext::calculateCoordinateOperation()

Returns: true on success

Since: QGIS 3.8

Definition at line 412 of file qgsgdalutils.cpp.

◆ resampleSingleBandRaster() [2/2]

bool QgsGdalUtils::resampleSingleBandRaster	(	GDALDatasetH	hSrcDS,
		GDALDatasetH	hDstDS,
		GDALResampleAlg	resampleAlg,
		const QgsCoordinateReferenceSystem &	sourceCrs,
		const QgsCoordinateReferenceSystem &	destinationCrs
	)

static

Resamples a single band raster to the destination dataset with different resolution and different CRS.

Ideally the source dataset should cover the whole area or the destination dataset.

Note: If possible, it is preferable to use the overload method with parameter pszCoordinateOperation. But if it is not possible or it fails to obtain the Proj coordinate operation string, this function is an alternative.

Returns: true on success

Since: QGIS 3.30

Definition at line 423 of file qgsgdalutils.cpp.

◆ rpcAwareAutoCreateWarpedVrt()

GDALDatasetH QgsGdalUtils::rpcAwareAutoCreateWarpedVrt	(	GDALDatasetH	hSrcDS,
		const char *	pszSrcWKT,
		const char *	pszDstWKT,
		GDALResampleAlg	eResampleAlg,
		double	dfMaxError,
		const GDALWarpOptions *	psOptionsIn
	)

static

This is a copy of GDALAutoCreateWarpedVRT optimized for imagery using RPC georeferencing that also sets RPC_HEIGHT in GDALCreateGenImgProjTransformer2 based on HEIGHT_OFF.

By default GDAL would assume that the imagery has zero elevation - if that is not the case, the image would not be shown in the correct location.

Since: QGIS 3.14

Definition at line 548 of file qgsgdalutils.cpp.

◆ rpcAwareCreateTransformer()

void * QgsGdalUtils::rpcAwareCreateTransformer	(	GDALDatasetH	hSrcDS,
		GDALDatasetH	hDstDS = `nullptr`,
		char **	papszOptions = `nullptr`
	)

static

This is a wrapper around GDALCreateGenImgProjTransformer2() that takes into account RPC georeferencing (it sets RPC_HEIGHT in GDALCreateGenImgProjTransformer2 based on HEIGHT_OFF).

By default GDAL would assume that the imagery has zero elevation - if that is not the case, the image would not be shown in the correct location.

Since: QGIS 3.16

Definition at line 568 of file qgsgdalutils.cpp.

◆ setupProxy()

void QgsGdalUtils::setupProxy ( )

static

Sets the gdal proxy variables.

Definition at line 678 of file qgsgdalutils.cpp.

◆ supportsRasterCreate()

bool QgsGdalUtils::supportsRasterCreate ( GDALDriverH driver )

static

Reads whether a driver supports GDALCreate() for raster purposes.

Parameters

driver GDAL driver

Returns: true if a driver supports GDALCreate() for raster purposes.

Definition at line 162 of file qgsgdalutils.cpp.

◆ validateCreationOptionsFormat()

QString QgsGdalUtils::validateCreationOptionsFormat	(	const QStringList &	createOptions,
		const QString &	format
	)

static

Validates creation options for a given format, regardless of layer.

Since: QGIS 3.10

Definition at line 532 of file qgsgdalutils.cpp.

◆ vrtMatchesLayerType()

bool QgsGdalUtils::vrtMatchesLayerType	(	const QString &	vrtPath,
		Qgis::LayerType	type
	)

static

Returns true if the VRT file at the specified path is a VRT matching the given layer type.

Since: QGIS 3.22

Definition at line 1023 of file qgsgdalutils.cpp.

◆ vsiArchiveFileExtensions()

QStringList QgsGdalUtils::vsiArchiveFileExtensions ( )

static

Returns a list of file extensions which correspond to archive style containers supported by GDAL (e.g.

"zip").

Since: QGIS 3.32

Definition at line 951 of file qgsgdalutils.cpp.

◆ vsiArchivePrefixes()

QStringList QgsGdalUtils::vsiArchivePrefixes ( )

static

Returns a list of vsi prefixes which correspond to archive style containers (eg vsizip).

Since: QGIS 3.32

Definition at line 887 of file qgsgdalutils.cpp.

◆ vsiHandlerType()

Qgis::VsiHandlerType QgsGdalUtils::vsiHandlerType ( const QString & prefix )

static

Returns the VSI handler type for a given VSI prefix.

Since: QGIS 3.40

Definition at line 977 of file qgsgdalutils.cpp.

◆ vsiNetworkFileSystems()

QList< QgsGdalUtils::VsiNetworkFileSystemDetails > QgsGdalUtils::vsiNetworkFileSystems ( )

static

Returns a list of available GDAL VSI network file systems.

Since: QGIS 3.40

Definition at line 900 of file qgsgdalutils.cpp.

◆ vsiPrefixForPath()

QString QgsGdalUtils::vsiPrefixForPath ( const QString & path )

static

Returns a the vsi prefix which corresponds to a file path, or an empty string if the path is not associated with a vsi prefix.

Since: QGIS 3.32

Definition at line 841 of file qgsgdalutils.cpp.

Friends And Related Symbol Documentation

◆ TestQgsGdalUtils

friend class TestQgsGdalUtils

friend

Definition at line 379 of file qgsgdalutils.h.

The documentation for this class was generated from the following files:

/build/qgis-3.41.0+git20241225+af5edcb665c+99sid/src/core/qgsgdalutils.h
/build/qgis-3.41.0+git20241225+af5edcb665c+99sid/src/core/qgsgdalutils.cpp

Classes

Static Public Member Functions

Friends

Detailed Description

Member Function Documentation

◆ applyVsiCredentialOptions()

◆ blockToSingleBandMemoryDataset() [1/3]

◆ blockToSingleBandMemoryDataset() [2/3]

◆ blockToSingleBandMemoryDataset() [3/3]

◆ createMultiBandMemoryDataset()

◆ createSingleBandMemoryDataset()

◆ createSingleBandTiffDataset()

◆ gdalDataTypeFromQgisDataType()

◆ gdalDocumentationUrlForDriver()

◆ gdalResamplingAlgorithm()

◆ helpCreationOptionsFormat()

◆ imageToMemoryDataset()

◆ isVsiArchiveFileExtension()

◆ isVsiArchivePrefix()

◆ multiLayerFileExtensions()

◆ papszFromStringList()

◆ pathIsCheapToOpen()

◆ resampleImage()

◆ resampleSingleBandRaster() [1/2]

◆ resampleSingleBandRaster() [2/2]

◆ rpcAwareAutoCreateWarpedVrt()

◆ rpcAwareCreateTransformer()

◆ setupProxy()

◆ supportsRasterCreate()

◆ validateCreationOptionsFormat()

◆ vrtMatchesLayerType()

◆ vsiArchiveFileExtensions()

◆ vsiArchivePrefixes()

◆ vsiHandlerType()

◆ vsiNetworkFileSystems()

◆ vsiPrefixForPath()

Friends And Related Symbol Documentation

◆ TestQgsGdalUtils