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Hi Even,
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<div class="">On 18/05/2017, at 9:12 PM, Even Rouault <<a href="mailto:even.rouault@spatialys.com" class="">even.rouault@spatialys.com</a>> wrote:</div>
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> </div>
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> Is is possible to directly write external overview to a S3 bucket? With GDAL</div>
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> 2.1.2 I get an error reporting that seek is not supported when writing to</div>
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> vsis3:</div>
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No, /vsis3/ only supports sequential writing in files (the original use case was to generate and upload a huge CSV file on the fly). I don't have all the details in mind but random writing might not be possible given the S3 API constraints, at least with the
multipart upload API which is used currently.</div>
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<div>OK thanks for clarifying the situation.</div>
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And another constraint of the current implementation is that a /vsis3/ file is either read-only or write-only, but not a mix of both, which would be needed for gdaladdo internal overviews. Perhaps external overview would work, but I'm not completely sure as
creating a TIFF file might require seeking.</div>
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Perhaps a fully fledged read-write-update file system would be possible, but that wasn't in my initial design constraints.</div>
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<div>For now we will work around the issue.</div>
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<div>Thank for your help.</div>
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<div>Cheers,</div>
<div>Jeremy</div>
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