[QGIS-Developer] webp for qgis server ?

[Lucie Nicolier]

>> Hi everyone,
>>
>> I upgraded the blog-post with all command lines I used and how I get 
>> the base TIF and the other formats from it.
>>
>> Hope to see the parameters I used will explain the results we got.
>>
>> I'm open to received recommendations to get better result.
>>
>> Stay here for more information.
>>
>> Regards,
>>
>> Lucie
>>
>> Lucie Nicolier
>> lucie at opengis.ch <mailto:lucie at opengis.ch>
>> +41 (0)79 276 67 76 <tel:+41792766776>
>>
>> OPENGIS.ch Logo <http://www.opengis.ch>
>>
>>
>> Le 09.06.2020 à 14:01, Matthias Kuhn a écrit :
>>>
>>> Thanks for the excellent questions Even
>>>
>>> Lucie has done the analysis and has all the parameters. She is not 
>>> in the office these days. Once she is back I hope she can share the 
>>> parameters and potentially also add a couple of additional rows to 
>>> the table with improved parameters.
>>>
>>> Sorry that I can't help more right now.
>>>
>>> Matthias
>>>
>>> On 6/9/20 1:56 PM, Even Rouault wrote:
>>>>
>>>> Matthias,
>>>>
>>>> thanks for the analysis. There are however a few unexpected results.
>>>>
>>>> 1) I'd expect gpkg pyramid_JPEG and COG_JPEG to have very similar 
>>>> sizes, even COG_JPEG being potentially slightly smaller.
>>>>
>>>> And I'd also expect COG_JPEG to be slighly faster (but with less 
>>>> confidence that my statement about size)
>>>>
>>>> Has by chance the source raster an alpha band ? In which case 
>>>> gpkg_pyramid_JPEG would have dropped it, whereas COG_JPEG will 
>>>> encode it as DEFLATE compressed mask, but still the difference is 
>>>> surprising
>>>>
>>>> Another explanation might be the block size. GPKG defaults to 
>>>> 256x256 tiles, whereas COG_JPEG to 512x512. Perhaps that affect 
>>>> compression efficiency. And performance? (depends if your bench 
>>>> maintains the GDAL raster opened between requests or not)
>>>>
>>>> If you didn't specify quality settings, both COG_JPEG and GPKG JPEG 
>>>> should use the same quality of 75%
>>>>
>>>> 2) For the same compression type, block sizes and number of 
>>>> overviews, MBTiles (the report doesn't specify the compression 
>>>> scheme for it) and GeoPacakge should also have similar sizes and 
>>>> performance. They are really close brothers, with just a few 
>>>> systems tables different.
>>>>
>>>> Even
>>>>
>>>> > Hi all,
>>>>
>>>> >
>>>>
>>>> > At OPENGIS.ch we have recently looked into different raster 
>>>> formats. The
>>>>
>>>> > results can be read here:
>>>>
>>>> > 
>>>> https://www.opengis.ch/2020/06/09/offline-wms-benchmarking-raster-formats-fo
>>>>
>>>> > r-qfield/
>>>>
>>>> >
>>>>
>>>> > Not that surprising, but one of the interesting findings was that 
>>>> webp
>>>>
>>>> > is very efficient. Low filesize, reasonable rendering performance,
>>>>
>>>> > support for transparency. In short, it has all the potential for 
>>>> being
>>>>
>>>> > used as default transport format for WM(T)S.
>>>>
>>>> >
>>>>
>>>> > Looking at our server implementation, this format is not 
>>>> supported. Did
>>>>
>>>> > someone ever think about or even look into that?
>>>>
>>>> >
>>>>
>>>> > Regards
>>>>
>>>> -- 
>>>>
>>>> Spatialys - Geospatial professional services
>>>>
>>>> http://www.spatialys.com
>>>>
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