gdalwarper.h File Reference

GDAL warper related entry points and definitions. More...

#include "gdal_alg.h"
#include "cpl_minixml.h"

Go to the source code of this file.

Classes
struct	GDALWarpOptions
	Warp control options for use with GDALWarpOperation::Initialize(). More...
class	GDALWarpKernel
	Low level image warping class. More...
class	GDALWarpOperation
	High level image warping class. More...
Typedefs
typedef int(*	GDALMaskFunc )(void *pMaskFuncArg, int nBandCount, GDALDataType eType, int nXOff, int nYOff, int nXSize, int nYSize, GByte **papabyImageData, int bMaskIsFloat, void *pMask)
typedef void *	GDALWarpOperationH
Enumerations
enum	GDALResampleAlg {   GRA_NearestNeighbour = 0, GRA_Bilinear = 1, GRA_Cubic = 2, GRA_CubicSpline = 3,   GRA_Lanczos = 4 }
Functions
CPLErr	GDALWarpNoDataMasker (void *pMaskFuncArg, int nBandCount, GDALDataType eType, int nXOff, int nYOff, int nXSize, int nYSize, GByte **papabyImageData, int bMaskIsFloat, void *pValidityMask)
CPLErr	GDALWarpDstAlphaMasker (void *pMaskFuncArg, int nBandCount, GDALDataType eType, int nXOff, int nYOff, int nXSize, int nYSize, GByte **, int bMaskIsFloat, void *pValidityMask)
CPLErr	GDALWarpSrcAlphaMasker (void *pMaskFuncArg, int nBandCount, GDALDataType eType, int nXOff, int nYOff, int nXSize, int nYSize, GByte **, int bMaskIsFloat, void *pValidityMask)
CPLErr	GDALWarpCutlineMasker (void *pMaskFuncArg, int nBandCount, GDALDataType eType, int nXOff, int nYOff, int nXSize, int nYSize, GByte **, int bMaskIsFloat, void *pValidityMask)
GDALWarpOptions *	GDALCreateWarpOptions (void)
void	GDALDestroyWarpOptions (GDALWarpOptions *)
GDALWarpOptions *	GDALCloneWarpOptions (const GDALWarpOptions *)
CPLXMLNode *	GDALSerializeWarpOptions (const GDALWarpOptions *)
GDALWarpOptions *	GDALDeserializeWarpOptions (CPLXMLNode *)
CPLErr	GDALReprojectImage (GDALDatasetH hSrcDS, const char *pszSrcWKT, GDALDatasetH hDstDS, const char *pszDstWKT, GDALResampleAlg eResampleAlg, double dfWarpMemoryLimit, double dfMaxError, GDALProgressFunc pfnProgress, void *pProgressArg, GDALWarpOptions *psOptions)
	Reproject image.
CPLErr	GDALCreateAndReprojectImage (GDALDatasetH hSrcDS, const char *pszSrcWKT, const char *pszDstFilename, const char *pszDstWKT, GDALDriverH hDstDriver, char **papszCreateOptions, GDALResampleAlg eResampleAlg, double dfWarpMemoryLimit, double dfMaxError, GDALProgressFunc pfnProgress, void *pProgressArg, GDALWarpOptions *psOptions)
GDALDatasetH	GDALAutoCreateWarpedVRT (GDALDatasetH hSrcDS, const char *pszSrcWKT, const char *pszDstWKT, GDALResampleAlg eResampleAlg, double dfMaxError, const GDALWarpOptions *psOptions)
	Create virtual warped dataset automatically.
GDALDatasetH	GDALCreateWarpedVRT (GDALDatasetH hSrcDS, int nPixels, int nLines, double *padfGeoTransform, GDALWarpOptions *psOptions)
	Create virtual warped dataset.
CPLErr	GDALInitializeWarpedVRT (GDALDatasetH hDS, GDALWarpOptions *psWO)
	Set warp info on virtual warped dataset.
GDALWarpOperationH	GDALCreateWarpOperation (const GDALWarpOptions *)
void	GDALDestroyWarpOperation (GDALWarpOperationH)
CPLErr	GDALChunkAndWarpImage (GDALWarpOperationH, int, int, int, int)
CPLErr	GDALChunkAndWarpMulti (GDALWarpOperationH, int, int, int, int)
CPLErr	GDALWarpRegion (GDALWarpOperationH, int, int, int, int, int, int, int, int)
CPLErr	GDALWarpRegionToBuffer (GDALWarpOperationH, int, int, int, int, void *, GDALDataType, int, int, int, int)

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Detailed Description

GDAL warper related entry points and definitions.

Eventually it is expected that this file will be mostly private to the implementation, and the public C entry points will be available in gdal_alg.h.

---

Enumeration Type Documentation

enum GDALResampleAlg

Warp Resampling Algorithm

Enumerator:

GRA_NearestNeighbour	Nearest neighbour (select on one input pixel)
GRA_Bilinear	Bilinear (2x2 kernel)
GRA_Cubic	Cubic Convolution Approximation (4x4 kernel)
GRA_CubicSpline	Cubic B-Spline Approximation (4x4 kernel)
GRA_Lanczos	Lanczos windowed sinc interpolation (6x6 kernel)

---

Function Documentation

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

Create virtual warped dataset automatically.

This function will create a warped virtual file representing the input image warped into the target coordinate system. A GenImgProj transformation is created to accomplish any required GCP/Geotransform warp and reprojection to the target coordinate system. The output virtual dataset will be "northup" in the target coordinate system. The GDALSuggestedWarpOutput() function is used to determine the bounds and resolution of the output virtual file which should be large enough to include all the input image

Note that the constructed GDALDatasetH will acquire one or more references to the passed in hSrcDS. Reference counting semantics on the source dataset should be honoured. That is, don't just GDALClose() it unless it was opened with GDALOpenShared().

The returned dataset will have no associated filename for itself. If you want to write the virtual dataset description to a file, use the GDALSetDescription() function (or SetDescription() method) on the dataset to assign a filename before it is closed.

Parameters:

	hSrcDS	The source dataset.
	pszSrcWKT	The coordinate system of the source image. If NULL, it will be read from the source image.
	pszDstWKT	The coordinate system to convert to. If NULL no change of coordinate system will take place.
	eResampleAlg	One of GRA_NearestNeighbour, GRA_Bilinear, GRA_Cubic or GRA_CubicSpline. Controls the sampling method used.
	dfMaxError	Maximum error measured in input pixels that is allowed in approximating the transformation (0.0 for exact calculations).
	psOptions	Additional warp options, normally NULL.

Returns:

NULL on failure, or a new virtual dataset handle on success.

References GDALWarpOptions::eResampleAlg, GDALApproxTransform(), GDALAutoCreateWarpedVRT(), GDALCreateApproxTransformer(), GDALCreateGenImgProjTransformer(), GDALCreateWarpedVRT(), GDALGenImgProjTransform(), GDALGetGCPCount(), GDALGetGCPProjection(), GDALGetProjectionRef(), GDALGetRasterCount(), GDALSetGenImgProjTransformerDstGeoTransform(), GDALSetProjection(), GDALSuggestedWarpOutput(), GDALWarpOptions::hSrcDS, GDALWarpOptions::nBandCount, GDALWarpOptions::panDstBands, GDALWarpOptions::panSrcBands, GDALWarpOptions::pfnTransformer, and GDALWarpOptions::pTransformerArg.

Referenced by GDALAutoCreateWarpedVRT().

CPLErr GDALChunkAndWarpImage	(	GDALWarpOperationH	hOperation,
		int	nDstXOff,
		int	nDstYOff,
		int	nDstXSize,
		int	nDstYSize
	)

See also:

GDALWarpOperation::ChunkAndWarpImage()

References GDALChunkAndWarpImage().

Referenced by GDALChunkAndWarpImage().

CPLErr GDALChunkAndWarpMulti	(	GDALWarpOperationH	hOperation,
		int	nDstXOff,
		int	nDstYOff,
		int	nDstXSize,
		int	nDstYSize
	)

See also:

GDALWarpOperation::ChunkAndWarpMulti()

References GDALChunkAndWarpMulti().

Referenced by GDALChunkAndWarpMulti().

GDALDatasetH GDALCreateWarpedVRT	(	GDALDatasetH	hSrcDS,
		int	nPixels,
		int	nLines,
		double *	padfGeoTransform,
		GDALWarpOptions *	psOptions
	)

Create virtual warped dataset.

This function will create a warped virtual file representing the input image warped based on a provided transformation. Output bounds and resolution are provided explicitly.

Note that the constructed GDALDatasetH will acquire one or more references to the passed in hSrcDS. Reference counting semantics on the source dataset should be honoured. That is, don't just GDALClose() it unless it was opened with GDALOpenShared().

Parameters:

	hSrcDS	The source dataset.
	nPixels	Width of the virtual warped dataset to create
	nLines	Height of the virtual warped dataset to create
	padfGeoTransform	Geotransform matrix of the virtual warped dataset to create
	psOptions	Warp options. Must be different from NULL.

Returns:

NULL on failure, or a new virtual dataset handle on success.

References GDALCreateWarpedVRT(), GDALGetRasterBand(), GDALRasterBand::GetRasterDataType(), GDALWarpOptions::hDstDS, and GDALWarpOptions::nBandCount.

Referenced by GDALAutoCreateWarpedVRT(), and GDALCreateWarpedVRT().

GDALWarpOperationH GDALCreateWarpOperation

(

const GDALWarpOptions *

psNewOptions

)

See also:

GDALWarpOperation::Initialize()

References GDALCreateWarpOperation(), and GDALWarpOperation::Initialize().

Referenced by GDALCreateWarpOperation().

void GDALDestroyWarpOperation

(

GDALWarpOperationH

hOperation

)

See also:

GDALWarpOperation::~GDALWarpOperation()

References GDALDestroyWarpOperation().

Referenced by GDALDestroyWarpOperation().

CPLErr GDALInitializeWarpedVRT	(	GDALDatasetH	hDS,
		GDALWarpOptions *	psWO
	)

Set warp info on virtual warped dataset.

Initializes all the warping information for a virtual warped dataset.

This method is the same as the C++ method VRTWarpedDataset::Initialize().

Parameters:

	hDS	dataset previously created with the VRT driver, and a SUBCLASS of "VRTWarpedDataset".
	psWO	the warp options to apply. Note that ownership of the transformation information is taken over by the function though everything else remains the property of the caller.

Returns:

CE_None on success or CE_Failure if an error occurs.

References GDALInitializeWarpedVRT().

Referenced by GDALInitializeWarpedVRT().

CPLErr GDALReprojectImage	(	GDALDatasetH	hSrcDS,
		const char *	pszSrcWKT,
		GDALDatasetH	hDstDS,
		const char *	pszDstWKT,
		GDALResampleAlg	eResampleAlg,
		double	dfWarpMemoryLimit,
		double	dfMaxError,
		GDALProgressFunc	pfnProgress,
		void *	pProgressArg,
		GDALWarpOptions *	psOptions
	)

Reproject image.

This is a convenience function utilizing the GDALWarpOperation class to reproject an image from a source to a destination. In particular, this function takes care of establishing the transformation function to implement the reprojection, and will default a variety of other warp options.

By default all bands are transferred, with no masking or nodata values in effect. No metadata, projection info, or color tables are transferred to the output file.

Parameters:

	hSrcDS	the source image file.
	pszSrcWKT	the source projection. If NULL the source projection is read from from hSrcDS.
	hDstDS	the destination image file.
	pszDstWKT	the destination projection. If NULL the destination projection will be read from hDstDS.
	eResampleAlg	the type of resampling to use.
	dfWarpMemoryLimit	the amount of memory (in bytes) that the warp API is allowed to use for caching. This is in addition to the memory already allocated to the GDAL caching (as per GDALSetCacheMax()). May be 0.0 to use default memory settings.
	dfMaxError	maximum error measured in input pixels that is allowed in approximating the transformation (0.0 for exact calculations).
	pfnProgress	a GDALProgressFunc() compatible callback function for reporting progress or NULL.
	pProgressArg	argument to be passed to pfnProgress. May be NULL.
	psOptions	warp options, normally NULL.

Returns:

CE_None on success or CE_Failure if something goes wrong.

References GDALWarpOperation::ChunkAndWarpImage(), GDALWarpOptions::eResampleAlg, GDALApproxTransform(), GDALCreateApproxTransformer(), GDALCreateGenImgProjTransformer(), GDALDestroyApproxTransformer(), GDALDestroyGenImgProjTransformer(), GDALGenImgProjTransform(), GDALGetRasterBand(), GDALGetRasterCount(), GDALGetRasterNoDataValue(), GDALGetRasterXSize(), GDALGetRasterYSize(), GDALWarpOptions::hDstDS, GDALWarpOptions::hSrcDS, GDALWarpOperation::Initialize(), GDALWarpOptions::nBandCount, GDALWarpOptions::padfSrcNoDataImag, GDALWarpOptions::padfSrcNoDataReal, GDALWarpOptions::panDstBands, GDALWarpOptions::panSrcBands, GDALWarpOptions::pfnProgress, GDALWarpOptions::pfnTransformer, GDALWarpOptions::pProgressArg, and GDALWarpOptions::pTransformerArg.

CPLErr GDALWarpRegion	(	GDALWarpOperationH	hOperation,
		int	nDstXOff,
		int	nDstYOff,
		int	nDstXSize,
		int	nDstYSize,
		int	nSrcXOff,
		int	nSrcYOff,
		int	nSrcXSize,
		int	nSrcYSize
	)

See also:

GDALWarpOperation::WarpRegion()

References GDALWarpRegion().

Referenced by GDALWarpRegion().

CPLErr GDALWarpRegionToBuffer	(	GDALWarpOperationH	hOperation,
		int	nDstXOff,
		int	nDstYOff,
		int	nDstXSize,
		int	nDstYSize,
		void *	pDataBuf,
		GDALDataType	eBufDataType,
		int	nSrcXOff,
		int	nSrcYOff,
		int	nSrcXSize,
		int	nSrcYSize
	)

See also:

GDALWarpOperation::WarpRegionToBuffer()

References GDALWarpRegionToBuffer().

Referenced by GDALWarpRegionToBuffer().