[gdal-dev] mosaicking is very slow

Rahkonen Jukka (MML) jukka.rahkonen at maanmittauslaitos.fi
Mon Jan 27 06:41:49 PST 2020


Hi,

Yes, you can change the tile size. It is documented in https://gdal.org/drivers/raster/gtiff.html, BLOCKXSIZE and BLOCKYSIZE. Make a controlled test and measure timings. Optimizing one thing may lead to something suboptimal in another place and what is optimal for me does not need to be optimal for you because of different source data and hardware.

-Jukka Rahkonen-
 
-----Alkuperäinen viesti-----
Lähettäjä: elmir <elmirgeo at protonmail.com> 
Lähetetty: maanantai 27. tammikuuta 2020 15.12
Vastaanottaja: Rahkonen Jukka (MML) <jukka.rahkonen at maanmittauslaitos.fi>
Kopio: Simon <twinbirds at protonmail.com>; gdal-dev at lists.osgeo.org
Aihe: Re: [gdal-dev] mosaicking is very slow

hi, thanks for nicely explaining. Can i change size of tile, 256*256; for speeding up?

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Monday, January 27, 2020 9:04 PM, Rahkonen Jukka (MML) <jukka.rahkonen at maanmittauslaitos.fi> wrote:

> Hi,
>
> If your source images are 4 GB then their size is at least 40000 by 40000 pixels, or more if they are compressed. If gdalwarp now needs 256256 pixels worth of source data, from a striped image it must read 25640000 (rowspixels per row), while from tiled source it can read just from 1 to 4 tiles, 256256 each.
>
> Pre-processing is additional load but if you pay 10 units extra for tiling and then save 100 units in warping you are still a winner.
>
> Make copies as
> gdal_translate -of GTiff -co tiled=yes -co compress=LZW input1.tif 
> copy1.tif
>
> Then create a new VRT file. Absolutely do not remove -co tiled=yes from the gdalwarp command or you'll demand GDAL to write at least 400000 pixels wide stripes.
>
> -Jukka Rahkonen-
>
> -----Alkuperäinen viesti-----
> Lähettäjä: Simon twinbirds at protonmail.com
> Lähetetty: maanantai 27. tammikuuta 2020 13.18
> Vastaanottaja: Rahkonen Jukka (MML) 
> jukka.rahkonen at maanmittauslaitos.fi
> Kopio: gdal-dev at lists.osgeo.org
> Aihe: Re: [gdal-dev] mosaicking is very slow
>
> Hi,
> Thanks for your answer. The source images are not tiled. So, how can I tile them? Is not it additional load? I will try removing these ones:
> --config GDAL_CACHEMAX 8000
> -co TILED=YES
>
> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
> On Monday, January 27, 2020 7:48 PM, jratike80 jukka.rahkonen at maanmittauslaitos.fi wrote:
>
> > Hi,
> > I would suggest to remove --config GDAL_CACHEMAX 8000 first. Then I 
> > would check if the source images are tiled. If they are not it could 
> > be worth an extra step to make tiled copies.
> > -Jukka Rahkonen-
> > Simon-4 wrote
> >
> > > Hello everyone,
> > > I am stiching aroung 100 geotiff images each of around 4gb. 
> > > However, translating the vrt file into geotiff is going on for days.
> > > gtranslate --config GDAL_CACHEMAX 8000 -co TILED=YES -co 
> > > COMPRESS=LZW -co BIGTIFF=YES infile.vrt outfile.tif How can I 
> > > speed up it?
> > > Thank you.
> > > Simon
> > > gdal-dev mailing list
> >
> > > gdal-dev at .osgeo
> >
> > > https://lists.osgeo.org/mailman/listinfo/gdal-dev
> >
> > --
> > Sent from: 
> > http://osgeo-org.1560.x6.nabble.com/GDAL-Dev-f3742093.html
> > gdal-dev mailing list
> > gdal-dev at lists.osgeo.org
> > https://lists.osgeo.org/mailman/listinfo/gdal-dev
>
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