[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
>>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-developer/attachments/20200707/d48fe744/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image.png
Type: image/png
Size: 6671 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/qgis-developer/attachments/20200707/d48fe744/attachment-0001.png>