Hi,all.
I want to correct the envisat N1 image with it's GCPs,this image
haven't geo-referenced information and projection,but it's GCPs have
geo-referenced information.However I can not get correct results,the
corrected image pixels are all zero.Here is my code:
GDALAllRegister();
GDALDriverH hDriver;
GDALDataType eDT;
GDALDatasetH hDstDS;
GDALDatasetH hSrcDS;
hSrcDS=GDALOpen("D:\\Users\\ASA_IMP_1PNUPA20070408_135835_000000162057_00082_26689_3974.N1",GA_ReadOnly);
CPLAssert(hSrcDS!=NULL);
int nGcpCount=GDALGetGCPCount(hSrcDS);
const GDAL_GCP *pGCPs=GDALGetGCPs(hSrcDS);
GDALWarpOptions *psWarpOptions = GDALCreateWarpOptions();
psWarpOptions->pTransformerArg=GDALCreateGCPTransformer(nGcpCount,pGCPs,1,0);
psWarpOptions->pfnTransformer=GDALGCPTransform;
psWarpOptions->eResampleAlg=GRA_NearestNeighbour;
psWarpOptions->hSrcDS=hSrcDS;
psWarpOptions->nBandCount=0;
psWarpOptions->pfnProgress=GDALTermProgress;
double adfDstGeoTransform[6];
int nPixels=0, nLines=0;
GDALSuggestedWarpOutput(psWarpOptions->hSrcDS, GDALGCPTransform,
psWarpOptions->pTransformerArg, adfDstGeoTransform, &nPixels,
&nLines);
hDriver=GDALGetDriverByName("GTiff");
CPLAssert(hDriver!=NULL);
eDT=GDALGetRasterDataType(GDALGetRasterBand(hSrcDS,1));
hDstDS=GDALCreate(hDriver,"D:\\Users\\warp.tif",nPixels,nLines,GDALGetRasterCount(hSrcDS),eDT,NULL);
CPLAssert(hDstDS!=NULL);
psWarpOptions->hDstDS=hDstDS;
char *pszDstWKT=NULL;
OGRSpatialReference oSRS;
oSRS.SetUTM(20,TRUE);
oSRS.SetWellKnownGeogCS("WGS84");
oSRS.exportToWkt(&pszDstWKT);
GDALSetProjection(hDstDS,pszDstWKT);
GDALSetGeoTransform(hDstDS,adfDstGeoTransform);
CPLFree(pszDstWKT);
GDALWarpOperation oOperation;
oOperation.Initialize(psWarpOptions);
oOperation.ChunkAndWarpImage(0,0,nPixels,nLines);
GDALDestroyGenImgProjTransformer(psWarpOptions->pTransformerArg);
GDALDestroyWarpOptions(psWarpOptions);
GDALClose(hDstDS);
GDALClose(hSrcDS);
That's Why?I turn to Anybody who once did this job for some advice. Thank
you!
Kind regards.
--
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