/** Apply a vertical shift grid to a source (DEM typically) dataset.
*
* hGridDataset will typically use WGS84 as horizontal datum (but this is
* not a requirement) and its values are the values to add to go from geoid
* elevations to WGS84 ellipsoidal heights.
*
* hGridDataset will be on-the-fly reprojected and resampled to the projection
* and resolution of hSrcDataset, using bilinear resampling by default.
*
* Both hSrcDataset and hGridDataset must be single band datasets, and have
* a valid geotransform and projection.
*
* On success, a reference will be taken on hSrcDataset and hGridDataset.
* Reference counting semantics on the source and grid datasets should be
* honoured. That is, don't just GDALClose() it, unless it was opened with
* GDALOpenShared(), but rather use GDALReleaseDataset() if wanting to
* immediately release the reference(s) and make the returned dataset the
* owner of them.
*
* Valid use cases:
*
* \code
* hSrcDataset = GDALOpen(...)
* hGridDataset = GDALOpen(...)
* hDstDataset = GDALApplyVerticalShiftGrid(hSrcDataset, hGridDataset, ...)
* GDALReleaseDataset(hSrcDataset);
* GDALReleaseDataset(hGridDataset);
* if( hDstDataset )
* {
* // Do things with hDstDataset
* GDALClose(hDstDataset) // will close hSrcDataset and hGridDataset
* }
* \endcode
*
* @param hSrcDataset source (DEM) dataset. Must not be NULL.
* @param hGridDataset vertical grid shift dataset. Must not be NULL.
* @param bInverse if set to FALSE, hGridDataset values will be added to
* hSrcDataset. If set to TRUE, they will be subtracted.
* @param dfSrcUnitToMeter the factor to convert values from hSrcDataset to
* meters (1.0 if source values are in meter).
* @param dfDstUnitToMeter the factor to convert shifted values from meter
* (1.0 if output values must be in meter).
* @param papszOptions list of options, or NULL. Supported options are:
* <ul>
* <li>RESAMPLING=NEAREST/BILINEAR/CUBIC. Defaults to BILINEAR.</li>
* <li>MAX_ERROR=val. Maximum error measured in input pixels that is allowed in
* approximating the transformation (0.0 for exact calculations). Defaults
* to 0.125</li>
* <li>DATATYPE=Byte/UInt16/Int16/Float32/Float64. Output data type. If not
* specified will be the same as the one of hSrcDataset.
* <li>ERROR_ON_MISSING_VERT_SHIFT=YES/NO. Whether a missing/nodata value in
* hGridDataset should cause I/O requests to fail. Default is NO (in which case
* 0 will be used)
* <li>SRC_SRS=srs_def. Override projection on hSrcDataset;
* </ul>
*
* @return a new dataset corresponding to hSrcDataset adjusted with
* hGridDataset, or NULL. If not NULL, it must be closed with GDALClose().
*
* @since GDAL 2.2
*/
GDALDatasetH GDALApplyVerticalShiftGrid( GDALDatasetH hSrcDataset,
GDALDatasetH hGridDataset,
int bInverse,
double dfSrcUnitToMeter,
double dfDstUnitToMeter,
const char* const* papszOptions )
{
VALIDATE_POINTER1( hSrcDataset, "GDALApplyVerticalShiftGrid", nullptr );
VALIDATE_POINTER1( hGridDataset, "GDALApplyVerticalShiftGrid", nullptr );
double adfSrcGT[6];
if( GDALGetGeoTransform(hSrcDataset, adfSrcGT) != CE_None )
{
CPLError(CE_Failure, CPLE_NotSupported,
"Source dataset has no geotransform.");
return nullptr;
}
const char* pszSrcProjection = CSLFetchNameValueDef(papszOptions,
"SRC_SRS",
GDALGetProjectionRef(hSrcDataset));
if( pszSrcProjection == nullptr || pszSrcProjection[0] == '\0' )
{
CPLError(CE_Failure, CPLE_NotSupported,
"Source dataset has no projection.");
return nullptr;
}
if( GDALGetRasterCount(hSrcDataset) != 1 )
{
CPLError(CE_Failure, CPLE_NotSupported,
"Only single band source dataset is supported.");
return nullptr;
}
double adfGridGT[6];
if( GDALGetGeoTransform(hGridDataset, adfGridGT) != CE_None )
{
CPLError(CE_Failure, CPLE_NotSupported,
"Grid dataset has no geotransform.");
return nullptr;
}
const char* pszGridProjection = GDALGetProjectionRef(hGridDataset);
if( pszGridProjection == nullptr || pszGridProjection[0] == '\0' )
{
CPLError(CE_Failure, CPLE_NotSupported,
"Grid dataset has no projection.");
return nullptr;
}
if( GDALGetRasterCount(hGridDataset) != 1 )
{
CPLError(CE_Failure, CPLE_NotSupported,
"Only single band grid dataset is supported.");
return nullptr;
}
GDALDataType eDT = GDALGetRasterDataType(GDALGetRasterBand(hSrcDataset,1));
const char* pszDataType = CSLFetchNameValue(papszOptions, "DATATYPE");
if( pszDataType )
eDT = GDALGetDataTypeByName(pszDataType);
if( eDT == GDT_Unknown )
{
CPLError(CE_Failure, CPLE_NotSupported,
"Invalid DATATYPE=%s", pszDataType);
return nullptr;
}
const int nSrcXSize = GDALGetRasterXSize(hSrcDataset);
const int nSrcYSize = GDALGetRasterYSize(hSrcDataset);
OGRSpatialReference oSRS;
CPLString osSrcProjection(pszSrcProjection);
oSRS.SetFromUserInput(osSrcProjection);
if( oSRS.IsCompound() )
{
OGR_SRSNode* poNode = oSRS.GetRoot()->GetChild(1);
if( poNode != nullptr )
{
char* pszWKT = nullptr;
poNode->exportToWkt(&pszWKT);
osSrcProjection = pszWKT;
CPLFree(pszWKT);
}
}
void* hTransform = GDALCreateGenImgProjTransformer3( pszGridProjection,
adfGridGT,
osSrcProjection,
adfSrcGT );
if( hTransform == nullptr )
return nullptr;
GDALWarpOptions* psWO = GDALCreateWarpOptions();
psWO->hSrcDS = hGridDataset;
psWO->eResampleAlg = GRA_Bilinear;
const char* pszResampling = CSLFetchNameValue(papszOptions, "RESAMPLING");
if( pszResampling )
{
if( EQUAL(pszResampling, "NEAREST") )
psWO->eResampleAlg = GRA_NearestNeighbour;
else if( EQUAL(pszResampling, "BILINEAR") )
psWO->eResampleAlg = GRA_Bilinear;
else if( EQUAL(pszResampling, "CUBIC") )
psWO->eResampleAlg = GRA_Cubic;
}
psWO->eWorkingDataType = GDT_Float32;
int bHasNoData = FALSE;
const double dfSrcNoData = GDALGetRasterNoDataValue(
GDALGetRasterBand(hGridDataset, 1), &bHasNoData );
if( bHasNoData )
{
psWO->padfSrcNoDataReal =
static_cast<double*>(CPLMalloc(sizeof(double)));
psWO->padfSrcNoDataReal[0] = dfSrcNoData;
}
psWO->padfDstNoDataReal = static_cast<double*>(CPLMalloc(sizeof(double)));
const bool bErrorOnMissingShift = CPLFetchBool( papszOptions,
"ERROR_ON_MISSING_VERT_SHIFT",
false );
psWO->padfDstNoDataReal[0] =
(bErrorOnMissingShift) ? -std::numeric_limits<float>::infinity() : 0.0;
psWO->papszWarpOptions = CSLSetNameValue(psWO->papszWarpOptions,
"INIT_DEST",
"NO_DATA");
psWO->pfnTransformer = GDALGenImgProjTransform;
psWO->pTransformerArg = hTransform;
const double dfMaxError = CPLAtof(CSLFetchNameValueDef(papszOptions,
"MAX_ERROR",
"0.125"));
if( dfMaxError > 0.0 )
{
psWO->pTransformerArg =
GDALCreateApproxTransformer( psWO->pfnTransformer,
psWO->pTransformerArg,
dfMaxError );
psWO->pfnTransformer = GDALApproxTransform;
GDALApproxTransformerOwnsSubtransformer(psWO->pTransformerArg, TRUE);
}
psWO->nBandCount = 1;
psWO->panSrcBands = static_cast<int *>(CPLMalloc(sizeof(int)));
psWO->panSrcBands[0] = 1;
psWO->panDstBands = static_cast<int *>(CPLMalloc(sizeof(int)));
psWO->panDstBands[0] = 1;
VRTWarpedDataset* poReprojectedGrid =
new VRTWarpedDataset(nSrcXSize, nSrcYSize);
// This takes a reference on hGridDataset
CPLErr eErr = poReprojectedGrid->Initialize(psWO);
CPLAssert(eErr == CE_None);
CPL_IGNORE_RET_VAL(eErr);
GDALDestroyWarpOptions(psWO);
poReprojectedGrid->SetGeoTransform(adfSrcGT);
poReprojectedGrid->AddBand(GDT_Float32, nullptr);
GDALApplyVSGDataset* poOutDS = new GDALApplyVSGDataset(
reinterpret_cast<GDALDataset*>(hSrcDataset),
poReprojectedGrid,
eDT,
CPL_TO_BOOL(bInverse),
dfSrcUnitToMeter,
dfDstUnitToMeter,
// Undocumented option. For testing only
atoi(CSLFetchNameValueDef(papszOptions, "BLOCKSIZE", "256")) );
poReprojectedGrid->ReleaseRef();
if( !poOutDS->IsInitOK() )
{
delete poOutDS;
return nullptr;
}
poOutDS->SetDescription( GDALGetDescription( hSrcDataset ) );
return reinterpret_cast<GDALDatasetH>(poOutDS);
}
