[gdal-dev] Re: Transposing image data using RasterIO

[Paul Mallas]

Yes, I tried this. I keep getting a segmentation fault doing it this way.

I will dig further, maybe something else is not right.

Regards,
Paul

On 6/17/2011 6:25 PM, Paul Mallas wrote:
> On 6/17/2011 5:41 PM, Frank Warmerdam wrote:
>> On 11-06-17 03:23 PM, Paul Mallas wrote:
>>> Hello,
>>>
>>> I am trying to transpose image data (i.e., swap lines and columns)
>>> and am
>>> struggling to make it work properly. I think this should be possible
>>> through
>>> RasterIO, but so far no luck. Any suggestions?
>>>
>>> My approach so far has been like this, with image nXsize by nYsize:
>>>
>>> void *pData = VSIMalloc2(nXSize, (GDALGetDataTypeSize(eType) / 8));
>>>
>>> for (int iLine = 0; iLine < nYSize; iLine++) {
>>>
>>> // Read in row (line)
>>> eErr = poSrcBand->RasterIO(GF_Read, 0, iLine, nXSize, 1, pData,
>>> nXSize, 1, eType, 0,0);
>>>
>>> // Now I want to write a column, nothing I tried here has worked
>>> eErr = poDstBand->RasterIO(GF_Write, .......
>>
>> Paul,
>>
>> You should be able to write this column wise like:
>>
>> poDstBand->RasterIO( GF_Write, iLine, 0, 1, nXSize,
>> pData, 1, nXSize, eType, 0, 0 );
>>
>> Note that this can be pretty inefficient depending on the format and
>> how it is blocked.
>>
>> Best regards,
>
> Hmm, I thought I tried this configuration. I will try again. Thank you
> for your time Frank.