GDAL
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VRTDataset Class Reference
Inheritance diagram for VRTDataset:
GDALDataset GDALMajorObject VRTPansharpenedDataset VRTWarpedDataset

Public Member Functions

 VRTDataset (int nXSize, int nYSize)
 
void SetNeedsFlush ()
 
virtual void FlushCache ()
 Flush all write cached data to disk. More...
 
void SetWritable (int bWritableIn)
 
virtual CPLErr CreateMaskBand (int nFlags)
 Adds a mask band to the dataset. More...
 
void SetMaskBand (VRTRasterBand *poMaskBand)
 
virtual const char * GetProjectionRef (void)
 Fetch the projection definition string for this dataset. More...
 
virtual CPLErr SetProjection (const char *)
 Set the projection reference string for this dataset. More...
 
virtual CPLErr GetGeoTransform (double *)
 Fetch the affine transformation coefficients. More...
 
virtual CPLErr SetGeoTransform (double *)
 Set the affine transformation coefficients. More...
 
virtual CPLErr SetMetadata (char **papszMD, const char *pszDomain="")
 Set metadata. More...
 
virtual CPLErr SetMetadataItem (const char *pszName, const char *pszValue, const char *pszDomain="")
 Set single metadata item. More...
 
virtual char ** GetMetadata (const char *pszDomain="")
 Fetch metadata. More...
 
virtual int GetGCPCount ()
 Get number of GCPs. More...
 
virtual const char * GetGCPProjection ()
 Get output projection for GCPs. More...
 
virtual const GDAL_GCPGetGCPs ()
 Fetch GCPs. More...
 
virtual CPLErr SetGCPs (int nGCPCount, const GDAL_GCP *pasGCPList, const char *pszGCPProjection)
 Assign GCPs. More...
 
virtual CPLErr AddBand (GDALDataType eType, char **papszOptions=NULL)
 Add a band to a dataset. More...
 
virtual char ** GetFileList ()
 Fetch files forming dataset. More...
 
virtual CPLErr IRasterIO (GDALRWFlag eRWFlag, int nXOff, int nYOff, int nXSize, int nYSize, void *pData, int nBufXSize, int nBufYSize, GDALDataType eBufType, int nBandCount, int *panBandMap, GSpacing nPixelSpace, GSpacing nLineSpace, GSpacing nBandSpace, GDALRasterIOExtraArg *psExtraArg)
 
virtual CPLXMLNodeSerializeToXML (const char *pszVRTPath)
 
virtual CPLErr XMLInit (CPLXMLNode *, const char *)
 
virtual CPLErr IBuildOverviews (const char *, int, int *, int, int *, GDALProgressFunc, void *)
 
GDALDatasetGetSingleSimpleSource ()
 
void BuildVirtualOverviews ()
 
void UnsetPreservedRelativeFilenames ()
 
- Public Member Functions inherited from GDALDataset
virtual ~GDALDataset ()
 Destroy an open GDALDataset. More...
 
int GetRasterXSize (void)
 Fetch raster width in pixels. More...
 
int GetRasterYSize (void)
 Fetch raster height in pixels. More...
 
int GetRasterCount (void)
 Fetch the number of raster bands on this dataset. More...
 
GDALRasterBandGetRasterBand (int)
 Fetch a band object for a dataset. More...
 
virtual void * GetInternalHandle (const char *)
 Fetch a format specific internally meaningful handle. More...
 
virtual GDALDriverGetDriver (void)
 Fetch the driver to which this dataset relates. More...
 
virtual const char * GetDriverName ()
 
virtual CPLErr AdviseRead (int nXOff, int nYOff, int nXSize, int nYSize, int nBufXSize, int nBufYSize, GDALDataType eDT, int nBandCount, int *panBandList, char **papszOptions)
 Advise driver of upcoming read requests. More...
 
virtual GDALAsyncReaderBeginAsyncReader (int nXOff, int nYOff, int nXSize, int nYSize, void *pBuf, int nBufXSize, int nBufYSize, GDALDataType eBufType, int nBandCount, int *panBandMap, int nPixelSpace, int nLineSpace, int nBandSpace, char **papszOptions)
 Sets up an asynchronous data request. More...
 
virtual void EndAsyncReader (GDALAsyncReader *)
 End asynchronous request. More...
 
CPLErr RasterIO (GDALRWFlag, int, int, int, int, void *, int, int, GDALDataType, int, int *, GSpacing, GSpacing, GSpacing, GDALRasterIOExtraArg *psExtraArg) CPL_WARN_UNUSED_RESULT
 Read/write a region of image data from multiple bands. More...
 
int Reference ()
 Add one to dataset reference count. More...
 
int Dereference ()
 Subtract one from dataset reference count. More...
 
GDALAccess GetAccess () const
 
int GetShared ()
 Returns shared flag. More...
 
void MarkAsShared ()
 Mark this dataset as available for sharing.
 
void MarkSuppressOnClose ()
 
char ** GetOpenOptions ()
 
CPLErr BuildOverviews (const char *, int, int *, int, int *, GDALProgressFunc, void *)
 Build raster overview(s) More...
 
void ReportError (CPLErr eErrClass, CPLErrorNum err_no, const char *fmt,...) CPL_PRINT_FUNC_FORMAT(4
 Emits an error related to a dataset. More...
 
virtual char ** GetMetadataDomainList ()
 Fetch list of metadata domains. More...
 
virtual int GetLayerCount ()
 Get the number of layers in this dataset. More...
 
virtual OGRLayerGetLayer (int)
 Fetch a layer by index. More...
 
virtual OGRLayerGetLayerByName (const char *)
 Fetch a layer by name. More...
 
virtual OGRErr DeleteLayer (int)
 Delete the indicated layer from the datasource. More...
 
virtual int TestCapability (const char *)
 Test if capability is available. More...
 
virtual OGRLayerCreateLayer (const char *pszName, OGRSpatialReference *poSpatialRef=NULL, OGRwkbGeometryType eGType=wkbUnknown, char **papszOptions=NULL)
 This method attempts to create a new layer on the dataset with the indicated name, coordinate system, geometry type. More...
 
virtual OGRLayerCopyLayer (OGRLayer *poSrcLayer, const char *pszNewName, char **papszOptions=NULL)
 Duplicate an existing layer. More...
 
virtual OGRStyleTableGetStyleTable ()
 Returns dataset style table. More...
 
virtual void SetStyleTableDirectly (OGRStyleTable *poStyleTable)
 Set dataset style table. More...
 
virtual void SetStyleTable (OGRStyleTable *poStyleTable)
 Set dataset style table. More...
 
virtual OGRLayerExecuteSQL (const char *pszStatement, OGRGeometry *poSpatialFilter, const char *pszDialect)
 Execute an SQL statement against the data store. More...
 
virtual void ReleaseResultSet (OGRLayer *poResultsSet)
 Release results of ExecuteSQL(). More...
 
int GetRefCount () const
 Fetch reference count. More...
 
int GetSummaryRefCount () const
 Fetch reference count of datasource and all owned layers. More...
 
OGRErr Release ()
 Drop a reference to this dataset, and if the reference count drops to one close (destroy) the dataset. More...
 
virtual OGRErr StartTransaction (int bForce=FALSE)
 For datasources which support transactions, StartTransaction creates a `transaction. More...
 
virtual OGRErr CommitTransaction ()
 For datasources which support transactions, CommitTransaction commits a transaction. More...
 
virtual OGRErr RollbackTransaction ()
 For datasources which support transactions, RollbackTransaction will roll back a datasource to its state before the start of the current transaction. More...
 
GDALSQLParseInfo * BuildParseInfo (swq_select *psSelectInfo, swq_select_parse_options *poSelectParseOptions)
 
void DestroyParseInfo (GDALSQLParseInfo *psParseInfo)
 
OGRLayerExecuteSQL (const char *pszStatement, OGRGeometry *poSpatialFilter, const char *pszDialect, swq_select_parse_options *poSelectParseOptions)
 
- Public Member Functions inherited from GDALMajorObject
int GetMOFlags ()
 
void SetMOFlags (int nFlagsIn)
 
virtual const char * GetDescription () const
 Fetch object description. More...
 
virtual void SetDescription (const char *)
 Set object description. More...
 
virtual const char * GetMetadataItem (const char *pszName, const char *pszDomain="")
 Fetch single metadata item. More...
 

Static Public Member Functions

static int Identify (GDALOpenInfo *)
 
static GDALDatasetOpen (GDALOpenInfo *)
 
static GDALDatasetOpenXML (const char *, const char *=NULL, GDALAccess eAccess=GA_ReadOnly)
 
static GDALDatasetCreate (const char *pszName, int nXSize, int nYSize, int nBands, GDALDataType eType, char **papszOptions)
 
static CPLErr Delete (const char *pszFilename)
 
- Static Public Member Functions inherited from GDALDataset
static GDALDataset ** GetOpenDatasets (int *pnDatasetCount)
 Fetch all open GDAL dataset handles. More...
 
static int IsGenericSQLDialect (const char *pszDialect)
 

Protected Member Functions

virtual int CloseDependentDatasets ()
 Drop references to any other datasets referenced by this dataset. More...
 
- Protected Member Functions inherited from GDALDataset
 GDALDataset (int bForceCachedIO)
 
void RasterInitialize (int, int)
 
void SetBand (int, GDALRasterBand *)
 
CPLErr BlockBasedRasterIO (GDALRWFlag, int, int, int, int, void *, int, int, GDALDataType, int, int *, GSpacing, GSpacing, GSpacing, GDALRasterIOExtraArg *psExtraArg) CPL_WARN_UNUSED_RESULT
 
void BlockBasedFlushCache ()
 
CPLErr BandBasedRasterIO (GDALRWFlag eRWFlag, int nXOff, int nYOff, int nXSize, int nYSize, void *pData, int nBufXSize, int nBufYSize, GDALDataType eBufType, int nBandCount, int *panBandMap, GSpacing nPixelSpace, GSpacing nLineSpace, GSpacing nBandSpace, GDALRasterIOExtraArg *psExtraArg) CPL_WARN_UNUSED_RESULT
 
CPLErr RasterIOResampled (GDALRWFlag eRWFlag, int nXOff, int nYOff, int nXSize, int nYSize, void *pData, int nBufXSize, int nBufYSize, GDALDataType eBufType, int nBandCount, int *panBandMap, GSpacing nPixelSpace, GSpacing nLineSpace, GSpacing nBandSpace, GDALRasterIOExtraArg *psExtraArg) CPL_WARN_UNUSED_RESULT
 
CPLErr ValidateRasterIOOrAdviseReadParameters (const char *pszCallingFunc, int *pbStopProcessingOnCENone, int nXOff, int nYOff, int nXSize, int nYSize, int nBufXSize, int nBufYSize, int nBandCount, int *panBandMap)
 
CPLErr TryOverviewRasterIO (GDALRWFlag eRWFlag, int nXOff, int nYOff, int nXSize, int nYSize, void *pData, int nBufXSize, int nBufYSize, GDALDataType eBufType, int nBandCount, int *panBandMap, GSpacing nPixelSpace, GSpacing nLineSpace, GSpacing nBandSpace, GDALRasterIOExtraArg *psExtraArg, int *pbTried)
 
int ValidateLayerCreationOptions (const char *const *papszLCO)
 
int EnterReadWrite (GDALRWFlag eRWFlag)
 
void LeaveReadWrite ()
 
void TemporarilyDropReadWriteLock ()
 
void ReacquireReadWriteLock ()
 
void DisableReadWriteMutex ()
 
int AcquireMutex ()
 
void ReleaseMutex ()
 
virtual OGRLayerICreateLayer (const char *pszName, OGRSpatialReference *poSpatialRef=NULL, OGRwkbGeometryType eGType=wkbUnknown, char **papszOptions=NULL)
 This method attempts to create a new layer on the dataset with the indicated name, coordinate system, geometry type. More...
 
OGRErr ProcessSQLCreateIndex (const char *)
 
OGRErr ProcessSQLDropIndex (const char *)
 
OGRErr ProcessSQLDropTable (const char *)
 
OGRErr ProcessSQLAlterTableAddColumn (const char *)
 
OGRErr ProcessSQLAlterTableDropColumn (const char *)
 
OGRErr ProcessSQLAlterTableAlterColumn (const char *)
 
OGRErr ProcessSQLAlterTableRenameColumn (const char *)
 
- Protected Member Functions inherited from GDALMajorObject
char ** BuildMetadataDomainList (char **papszList, int bCheckNonEmpty,...) CPL_NULL_TERMINATED
 Helper function for custom implementations of GetMetadataDomainList() More...
 

Friends

class VRTRasterBand
 

Additional Inherited Members

- Protected Attributes inherited from GDALDataset
GDALDriverpoDriver
 
GDALAccess eAccess
 
int nRasterXSize
 
int nRasterYSize
 
int nBands
 
GDALRasterBand ** papoBands
 
int nOpenFlags
 
int nRefCount
 
GByte bForceCachedIO
 
GByte bShared
 
GByte bIsInternal
 
GByte bSuppressOnClose
 
GDALDefaultOverviews oOvManager
 
char ** papszOpenOptions
 
OGRStyleTablem_poStyleTable
 
- Protected Attributes inherited from GDALMajorObject
int nFlags
 
CPLString sDescription
 
GDALMultiDomainMetadata oMDMD
 

Member Function Documentation

CPLErr VRTDataset::AddBand ( GDALDataType  eType,
char **  papszOptions = NULL 
)
virtual

Add a band to a dataset.

This method will add a new band to the dataset if the underlying format supports this action. Most formats do not.

Note that the new GDALRasterBand is not returned. It may be fetched after successful completion of the method by calling GDALDataset::GetRasterBand(GDALDataset::GetRasterCount()) as the newest band will always be the last band.

Parameters
eTypethe data type of the pixels in the new band.
papszOptionsa list of NAME=VALUE option strings. The supported options are format specific. NULL may be passed by default.
Returns
CE_None on success or CE_Failure on failure.

Reimplemented from GDALDataset.

Reimplemented in VRTPansharpenedDataset, and VRTWarpedDataset.

int VRTDataset::CloseDependentDatasets ( )
protectedvirtual

Drop references to any other datasets referenced by this dataset.

This method should release any reference to other datasets (e.g. a VRT dataset to its sources), but not close the current dataset itself.

If at least, one reference to a dependent dataset has been dropped, this method should return TRUE. Otherwise it should return FALSE. (Failure to return the proper value might result in infinite loop)

This method can be called several times on a given dataset. After the first time, it should not do anything and return FALSE.

The driver implementation may choose to destroy its raster bands, so be careful not to call any method on the raster bands afterwards.

Basically the only safe action you can do after calling CloseDependentDatasets() is to call the destructor.

Note: the only legitimate caller of CloseDependentDatasets() is GDALDriverManager::~GDALDriverManager()

Returns
TRUE if at least one reference to another dataset has been dropped.

Reimplemented from GDALDataset.

Reimplemented in VRTPansharpenedDataset, and VRTWarpedDataset.

CPLErr VRTDataset::CreateMaskBand ( int  nFlagsIn)
virtual

Adds a mask band to the dataset.

The default implementation of the CreateMaskBand() method is implemented based on similar rules to the .ovr handling implemented using the GDALDefaultOverviews object. A TIFF file with the extension .msk will be created with the same basename as the original file, and it will have one band. The mask images will be deflate compressed tiled images with the same block size as the original image if possible.

Note that if you got a mask band with a previous call to GetMaskBand(), it might be invalidated by CreateMaskBand(). So you have to call GetMaskBand() again.

Since
GDAL 1.5.0
Parameters
nFlagsignored. GMF_PER_DATASET will be assumed.
Returns
CE_None on success or CE_Failure on an error.
See also
http://trac.osgeo.org/gdal/wiki/rfc15_nodatabitmask

Reimplemented from GDALDataset.

void VRTDataset::FlushCache ( void  )
virtual

Flush all write cached data to disk.

Any raster (or other GDAL) data written via GDAL calls, but buffered internally will be written to disk.

The default implementation of this method just calls the FlushCache() method on each of the raster bands and the SyncToDisk() method on each of the layers. Conceptionally, calling FlushCache() on a dataset should include any work that might be accomplished by calling SyncToDisk() on layers in that dataset.

Using this method does not prevent use from calling GDALClose() to properly close a dataset and ensure that important data not addressed by FlushCache() is written in the file.

This method is the same as the C function GDALFlushCache().

Reimplemented from GDALDataset.

char ** VRTDataset::GetFileList ( void  )
virtual

Fetch files forming dataset.

Returns a list of files believed to be part of this dataset. If it returns an empty list of files it means there is believed to be no local file system files associated with the dataset (for instance a virtual dataset). The returned file list is owned by the caller and should be deallocated with CSLDestroy().

The returned filenames will normally be relative or absolute paths depending on the path used to originally open the dataset. The strings will be UTF-8 encoded.

This method is the same as the C GDALGetFileList() function.

Returns
NULL or a NULL terminated array of file names.

Reimplemented from GDALDataset.

Reimplemented in VRTPansharpenedDataset, and VRTWarpedDataset.

int VRTDataset::GetGCPCount ( )
virtual

Get number of GCPs.

This method is the same as the C function GDALGetGCPCount().

Returns
number of GCPs for this dataset. Zero if there are none.

Reimplemented from GDALDataset.

const char * VRTDataset::GetGCPProjection ( )
virtual

Get output projection for GCPs.

This method is the same as the C function GDALGetGCPProjection().

The projection string follows the normal rules from GetProjectionRef().

Returns
internal projection string or "" if there are no GCPs. It should not be altered, freed or expected to last for long.

Reimplemented from GDALDataset.

const GDAL_GCP * VRTDataset::GetGCPs ( )
virtual

Fetch GCPs.

This method is the same as the C function GDALGetGCPs().

Returns
pointer to internal GCP structure list. It should not be modified, and may change on the next GDAL call.

Reimplemented from GDALDataset.

CPLErr VRTDataset::GetGeoTransform ( double *  padfTransform)
virtual

Fetch the affine transformation coefficients.

Fetches the coefficients for transforming between pixel/line (P,L) raster space, and projection coordinates (Xp,Yp) space.

Xp = padfTransform[0] + P*padfTransform[1] + L*padfTransform[2];
Yp = padfTransform[3] + P*padfTransform[4] + L*padfTransform[5];

In a north up image, padfTransform[1] is the pixel width, and padfTransform[5] is the pixel height. The upper left corner of the upper left pixel is at position (padfTransform[0],padfTransform[3]).

The default transform is (0,1,0,0,0,1) and should be returned even when a CE_Failure error is returned, such as for formats that don't support transformation to projection coordinates.

This method does the same thing as the C GDALGetGeoTransform() function.

Parameters
padfTransforman existing six double buffer into which the transformation will be placed.
Returns
CE_None on success, or CE_Failure if no transform can be fetched.

Reimplemented from GDALDataset.

char ** VRTDataset::GetMetadata ( const char *  pszDomain = "")
virtual

Fetch metadata.

The returned string list is owned by the object, and may change at any time. It is formatted as a "Name=value" list with the last pointer value being NULL. Use the CPL StringList functions such as CSLFetchNameValue() to manipulate it.

Note that relatively few formats return any metadata at this time.

This method does the same thing as the C function GDALGetMetadata().

Parameters
pszDomainthe domain of interest. Use "" or NULL for the default domain.
Returns
NULL or a string list.

Reimplemented from GDALDataset.

const char * VRTDataset::GetProjectionRef ( void  )
virtual

Fetch the projection definition string for this dataset.

Same as the C function GDALGetProjectionRef().

The returned string defines the projection coordinate system of the image in OpenGIS WKT format. It should be suitable for use with the OGRSpatialReference class.

When a projection definition is not available an empty (but not NULL) string is returned.

Returns
a pointer to an internal projection reference string. It should not be altered, freed or expected to last for long.
See also
http://www.gdal.org/osr_tutorial.html

Reimplemented from GDALDataset.

CPLErr VRTDataset::SetGCPs ( int  nGCPCount,
const GDAL_GCP pasGCPList,
const char *  pszGCPProjection 
)
virtual

Assign GCPs.

This method is the same as the C function GDALSetGCPs().

This method assigns the passed set of GCPs to this dataset, as well as setting their coordinate system. Internally copies are made of the coordinate system and list of points, so the caller remains responsible for deallocating these arguments if appropriate.

Most formats do not support setting of GCPs, even formats that can handle GCPs. These formats will return CE_Failure.

Parameters
nGCPCountnumber of GCPs being assigned.
pasGCPListarray of GCP structures being assign (nGCPCount in array).
pszGCPProjectionthe new OGC WKT coordinate system to assign for the GCP output coordinates. This parameter should be "" if no output coordinate system is known.
Returns
CE_None on success, CE_Failure on failure (including if action is not supported for this format).

Reimplemented from GDALDataset.

CPLErr VRTDataset::SetGeoTransform ( double *  padfTransform)
virtual

Set the affine transformation coefficients.

See GetGeoTransform() for details on the meaning of the padfTransform coefficients.

This method does the same thing as the C GDALSetGeoTransform() function.

Parameters
padfTransforma six double buffer containing the transformation coefficients to be written with the dataset.
Returns
CE_None on success, or CE_Failure if this transform cannot be written.

Reimplemented from GDALDataset.

CPLErr VRTDataset::SetMetadata ( char **  papszMetadataIn,
const char *  pszDomain = "" 
)
virtual

Set metadata.

The C function GDALSetMetadata() does the same thing as this method.

Parameters
papszMetadataInthe metadata in name=value string list format to apply.
pszDomainthe domain of interest. Use "" or NULL for the default domain.
Returns
CE_None on success, CE_Failure on failure and CE_Warning if the metadata has been accepted, but is likely not maintained persistently by the underlying object between sessions.

Reimplemented from GDALMajorObject.

CPLErr VRTDataset::SetMetadataItem ( const char *  pszName,
const char *  pszValue,
const char *  pszDomain = "" 
)
virtual

Set single metadata item.

The C function GDALSetMetadataItem() does the same thing as this method.

Parameters
pszNamethe key for the metadata item to fetch.
pszValuethe value to assign to the key.
pszDomainthe domain to set within, use NULL for the default domain.
Returns
CE_None on success, or an error code on failure.

Reimplemented from GDALMajorObject.

Reimplemented in VRTWarpedDataset.

CPLErr VRTDataset::SetProjection ( const char *  pszProjection)
virtual

Set the projection reference string for this dataset.

The string should be in OGC WKT or PROJ.4 format. An error may occur because of incorrectly specified projection strings, because the dataset is not writable, or because the dataset does not support the indicated projection. Many formats do not support writing projections.

This method is the same as the C GDALSetProjection() function.

Parameters
pszProjectionprojection reference string.
Returns
CE_Failure if an error occurs, otherwise CE_None.

Reimplemented from GDALDataset.


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

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