[Gdal-dev] r.out.gdal vs gdal_translate vs gdalwarp

[Frank Warmerdam]

Maciej Sieczka wrote:
> 'Frank Warmerdam-2' wrote:
> 
>> gdalwarp uses very different library interfaces and io strategies from
>> gdal_translate.  So in some circumstances the output may differ.
> 
>> On careful review, the difference in the file in question is because
>> gdal_translate uses the TIFFWriteScanline() interface to write the output
>> file from within GTiffDataset::CreateCopy(), and this only writes as much
>> of the final 'strip' of the file as is required to complete image area.
>> But gdalwarp goes through the blockio interface which writes the complete
>> final strip, even the portion that falls off the end of the file.
> 
> Frank,
> 
> Thanks much for your answer! I'm so glad the hear this is not a data
> corruption issue or whatsoever. 
> 
> However, wouldn't you consider it a missfeature that gdalwarp creates circa
> 25% bigger GeoTIFFs than gdal_translate does? The bigger deal it is the
> bigger is the input dataset.  For me it is quite a difference whether I get
> a 3 GB or 4 GB raster. Do you think gdalwarp could follow gdal_translate in
> this regard? If possible of course.

Maciek,

The particular problem I saw in the case I analysed should actually get
less and less significant as the dataset gets larger.  If you are seeing
much larger files for big files then a different issue is likely to
be coming into play.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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