[gdal-dev] read whole elevation data from geotif to vector[x][y]

[Robert Grah]

Hi Peb,

thanks for the hint. Thats really simple. Maybe i need this in the future.

Cheers,
Rob

---- Ein Mi, 18 Jun 2014 05:20:21 -0700 peb aryan <peb.aryan at student.tuwien.ac.at> hat geschrieben ---- 

>Hi Robert, 
>
>if you use opencv there is an easy way to pass buffer from RasterIO to a cv::Mat
>
>double *padRasterData = (double*)CPLMalloc(iGridsizeX*iGridsizeY*sizeof(double));
> 
>
>h_dataset->RasterIO(GF_Read, 0, 0, iGridsizeX, iGridsizeY, padRasterData, iGridsizeX, iGridsizeY, GDT_Float64, 1,NULL,0,0,0);
>
>
>cv::Mat img = cv::Mat(iGridsizeY, iGridsizeX, CV_64F, &padRasterData[0]);
> 
>
>
>...
>
>
>CPLFree( padRasterData );
>
>
>
>cheers,
>
>
>peb
>
>
>
>On Tue, Jun 17, 2014 at 8:56 PM, Robert Grah <smilingmolecule at web.de> wrote:
> Hallo,
> 
> i think this question is somehow a bit stupid but I have to ask it anyway because i can not find a good working solution.
> I try to read the whole elevation data from a band of a GeoTiff image into a c++ 2d vector so that I can read the values like vector[x][y].
> I also like to convert the data to an image and perform other operations.
> 
> I tried it like this, but this gives me the data in a strange order:
> 
> poBand->RasterIO( GF_Read, 0, 0, nXSize, nYSize,
>  pafScanline2, nXSize, nYSize, GDT_Float32,
>  0, 0 );
>  int totalCount = 0;
>  for (int i = 0; i GetXSize(); i++){
> 
>  vector yVal;
>  for (int j = 0; j GetYSize(); j++){
>  yVal.push_back(pafScanline2[totalCount]);
>  totalCount++;
>  }
>  altData.push_back(yVal);
>  }
> 
> 
> I also tried to read every single value step by step, but this was really slow.
> Is there an easy way to get the values ordered like the pixels of an image?
> From left to right and top to bottom? I think i am overlooking something...
> 
> Cheers,
> Robert
> 
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