James, I don't have a lot of time, but I can address some things quickly. Blocksize and raster size are not necessarily the same thing. In some datasets, a block is represented as a tile, in scanline oriented data, it is represented as one scanline, or a row. To obtain the x and y size of the data set, use poDataset->GetRaster[XY]Size(). This should report the values you are looking for. To access all of the data, loop over the scanlines and read in one at a time, or read in the entire raster into one buffer. Hope that helps.
kss /** * * Kyle Shannon * ksshan...@gmail.com * */ On Mon, Aug 15, 2011 at 13:09, James Sulzman <sulz...@casco.net> wrote: > Hi All,**** > > ** ** > > I could use a little help, and it would be greatly appreciated.**** > > ** ** > > Goal: Write a c++ program in MS Visual Studio 2010 (on win7 x64 machine) > that reads in a netCDF file. Compile/build program in Visual Studio 2010 > Release or Debug x64. Execute the program.**** > > The netCDF file I am trying to read in, has one variable in it. That > variable is a 3d raster 76x40x93 of float32 type.**** > > ** ** > > Steps I have taken:**** > > **1. **Download binaries from > http://www.gisinternals.com/sdk/PackageList.aspx?file=release-1600-x64-gdal-1-8-mapserver-6-0.zip > **** > > **2. **Create .lib files from .dll(s)**** > > **3. **Follow instruction from download binary site, paths/linkers > to library and gdalplugins etc..**** > > **4. **Use code from API tutorial for c++ > http://www.gdal.org/gdal_tutorial.html, also pasted below**** > > **5. **Compile the program (everything compiles fine).**** > > **6. **Run the program, does not bomb, but offers bad results.**** > > **7. **If you look at the c++ code tutorial in step 4 it has various > print statements. Here are the results from those print statements**** > > ** ** > > Driver: netCDF/Network Common Data Format**** > > Size is 76x40x93**** > > Projection is ‘ ’**** > > Block=76x1 Type=Float32, ColorInterp=Undefinded**** > > Min=72.905d Max 115.625d**** > > Data=100.216d**** > > ** ** > > Problem:**** > > ** ** > > When I get a “band” and get the block size, the block size is reported as > 76x1 (as in the snips below). I expected the block size to be 76x40**** > > ** ** > > poBand = poDataset->GetRasterBand( 1 );**** > > poBand->GetBlockSize( &nBlockXSize, &nBlockYSize );**** > > ** ** > > When I read the block (putting the snip below in a nested loop for column > and row) I get the proper data in that 76x1 (76 values) block, but I can’t > move onto the next row (ie row > 0). Which makes sense because the block is > only 76x1. Also, if I get band “2” the same thing, good data, but only one > column to work with. What am I missing? How do I retrieve the full band of > 76x40? I even tried a JPEG file and got similar results? **** > > ** ** > > ** ** > > poBand->RasterIO( GF_Read, column, row, nXSize, 1, **** > > pafScanline, nXSize, 1, GDT_Float32, **** > > 0, 0 );**** > > ** ** > > ** ** > > Thanks in advance for any help or advice,**** > > ** ** > > James**** > > ** ** > > ** ** > > My program**** > > ** ** > > ** ** > > typedef __int64 _OFF_T;**** > > #include "gdal.h"**** > > #include "gdal_priv.h"**** > > #include "netcdf.h"**** > > #include "gdal_frmts.h"**** > > #include "netcdfdataset.h"**** > > #include "cpl_config.h"**** > > #include "cpl_conv.h"**** > > #include "cpl_error.h"**** > > #include "cpl_hash_set.h"**** > > #include "cpl_port.h"**** > > #include "cpl_string.h"**** > > #include "cpl_vsi.h"**** > > #include "cpl_minixml.h"**** > > #include "gdal_pam.h"**** > > #include "gdal_version.h"**** > > #include "gdal_vrt.h"**** > > #include "ogr_core.h"**** > > #include "ogr_spatialref.h"**** > > #include "ogr_srs_api.h"**** > > ** ** > > #include <iostream>**** > > using namespace std;**** > > //const char *pszFilename = "\\IMG_3527.jpg";**** > > //const char *pszFilename = "\\hada2eugsi.nc";**** > > const char *pszFilename = "\\james_test.nc";**** > > ** ** > > //const char *pszFilename = "\\CRUTEM3.nc";**** > > const char *netcdfmeta ("");**** > > char ** ppinfo;**** > > int * pncid; **** > > int main()**** > > {**** > > **** > > **** > > GDALAllRegister();**** > > **** > > **** > > **** > > GDALDriver *poDriver = (GDALDriver *) GDALGetDriverByName( "VRT" ); > **** > > **** > > poDataset = (GDALDataset *) GDALOpen( pszFilename, GA_ReadOnly );** > ** > > **** > > **** > > ** ** > > GDALGetMetadata(poDataset,netcdfmeta);**** > > **** > > //poDataset->GetPamInfo();**** > > poDataset->GetMetadata(netcdfmeta);**** > > GDALOpenInfo(pszFilename, GA_ReadOnly ,ppinfo);**** > > //GDALGetGeoTransform( GDALDatasetH, double * );**** > > **** > > if( poDataset == NULL )**** > > {**** > > printf( "did not open file");**** > > }**** > > double adfGeoTransform[6];**** > > ** ** > > printf( "Driver: %s/%s\n",**** > > poDataset->GetDriver()->GetDescription(), **** > > poDataset->GetDriver()->GetMetadataItem( GDAL_DMD_LONGNAME ) ); > **** > > ** ** > > printf( "Size is %dx%dx%d\n", **** > > poDataset->GetRasterXSize(), poDataset->GetRasterYSize(),**** > > poDataset->GetRasterCount() );**** > > ** ** > > if( poDataset->GetProjectionRef() != NULL )**** > > printf( "Projection is `%s'\n", poDataset->GetProjectionRef() );** > ** > > ** ** > > if( poDataset->GetGeoTransform( adfGeoTransform ) == CE_None )**** > > {**** > > printf( "Origin = (%.6f,%.6f)\n",**** > > adfGeoTransform[0], adfGeoTransform[3] );**** > > ** ** > > printf( "Pixel Size = (%.6f,%.6f)\n",**** > > adfGeoTransform[1], adfGeoTransform[5] );**** > > }**** > > GDALRasterBand *poBand;**** > > int nBlockXSize, nBlockYSize;**** > > int bGotMin, bGotMax;**** > > double adfMinMax[2];**** > > **** > > poBand = poDataset->GetRasterBand( 1 );**** > > **** > > **** > > poBand->GetBlockSize( &nBlockXSize, &nBlockYSize );**** > > printf( "Block=%dx%d Type=%s, ColorInterp=%s\n",**** > > nBlockXSize, nBlockYSize,**** > > GDALGetDataTypeName(poBand->GetRasterDataType()),**** > > GDALGetColorInterpretationName(**** > > poBand->GetColorInterpretation()) );**** > > ** ** > > adfMinMax[0] = poBand->GetMinimum( &bGotMin );**** > > adfMinMax[1] = poBand->GetMaximum( &bGotMax );**** > > if( ! (bGotMin && bGotMax) )**** > > GDALComputeRasterMinMax((GDALRasterBandH)poBand, TRUE, > adfMinMax);**** > > ** ** > > printf( "Min=%.3fd, Max=%.3f\n", adfMinMax[0], adfMinMax[1] );**** > > **** > > if( poBand->GetOverviewCount() > 0 )**** > > printf( "Band has %d overviews.\n", poBand->GetOverviewCount() > );**** > > ** ** > > if( poBand->GetColorTable() != NULL )**** > > printf( "Band has a color table with %d entries.\n", **** > > poBand->GetColorTable()->GetColorEntryCount() );**** > > float *pafScanline;**** > > int nXSize = poBand->GetXSize();**** > > ** ** > > pafScanline = (float *) CPLMalloc(sizeof(float)*nXSize);**** > > poBand->RasterIO( GF_Read, 0, 0, nXSize, 1, **** > > pafScanline, nXSize, 1, GDT_Float32, **** > > 0, 0 );**** > > printf( "data=%.3fd", *pafScanline );**** > > **** > > GDALClose(poDataset);**** > > }**** > > ** ** > > ** ** > > ** ** > > _______________________________________________ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/gdal-dev >
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