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

[Chaitanya kumar CH]

Paul,

Please check that you used the right values for XSize and YSize.

On Wed, Jun 22, 2011 at 6:39 PM, Paul Mallas <pmallas at rsmas.miami.edu>wrote:

> 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.
>>
>
>
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-- 
Best regards,
Chaitanya kumar CH.
/tʃaɪθənjə/ /kʊmɑr/
+91-9494447584
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