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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