[gdal-dev] Tiling and Overviews disappear after compressing with LZW

[Vincent Schut]

On 12/05/13 16:39, Vincent Schut wrote:
> On 12/05/13 16:21, Ammar wrote:
>> Hello list,
>>
>> I am new to GDAL and I have been using the utilities to process and 
>> prepare TIFF  to create a mosaic in Geoserver. I am expermineting 
>> with different compression methods and I have noticed that after 
>> compressing a file with LZW, the previously created tiles and 
>> overviews disappear!
>>  what I did was:
>>
>> gdal_translate -a_srs "EPSG:3011" -co "TILED=YES" -co 
>> "BLOCKXSIZE=512" -co "BLOCKYSIZE=512" in.tif out.tif
>>
>> gdaladdo -r average file.tif 2 4 8 16 32//Adding the overviews
>>
>> gdal_translate -co compress=LZW in.tif out.tif
>>
>> After the compression, I got the original block size and with no 
>> overviews!
>>
>> Any ideas, thoughts or tips will be appreciated.
>
> Hello Ammar,
>
> the default for gdal_translate is no tiling, no compression, and don't 
> copy overviews. So your last gdal_translate command effectively 
> removes all tiling, overviews and compression. If you want to have a 
> tiled and compressed file, add the '-co compress=lzw" to your first 
> gdal_translate command, which will create a tiled and compressed 
> 'out.tif'. Then add overviews to that with gdaladdo. If I'm not 
> mistaken, the overviews use the settings from the main dataset, so 
> would also use lzw compression.
>
> Best,
> Vincent Schut.

Correction: that should of course read: "So your last gdal_translate 
command effectively removes all tiling and overviews, while adding lzw 
compression."
>>
>> //Ammar
>>
>>
>>
>>
>>
>>
>>
>>
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