[gdal-dev] What is the maximum '-wm' I can use with 64bit gdalwarp?

[Simen Langseth]

Dear Even Rouault

Whether I use '-multi' or not, '-wm 1024' works, but '-wm 3024' does not
work in my PC.

I re-tested it, and again with in a very few minutes, a completely black
image is produced.

Thanks for your support.


On Wed, Dec 24, 2014 at 7:30 PM, Even Rouault <even.rouault at spatialys.com>
wrote:

> Le mercredi 24 décembre 2014 11:19:14, Simen Langseth a écrit :
> > Dear Even Rouault
> >
> > Thanks for your answer.
> >
> > When I used more than 1024 mb for sub-sampling an image, strangely with
> in
> > few minutes, a completely black image is produced.
>
> Hum, I'm just fixing a but wher putting more in -wm caused issue but it was
> very specific : http://trac.osgeo.org/gdal/ticket/5789
>
> > Using 1024 is not sufficient because my input file is around 300GB.
>
> Eh, read again what I wrote : "putting more warp memory will not
> necessarily
> need to more performance". -wm is the size of individual chunks that will
> be
> warped. Working on very big chunks is actually detrimental if you want to
> use
> -multi since there will be less opportunity to parallelize I/O and CPU
> bound
> operations.
> If not already done, you'll get probably much more performance by for
> example
> ensuring you output to a tiled GeoTIFF, by adding -co TILED=YES
>
> > I could
> > not figure out the problem. I am also using '-multi' parameter.
> > There is no problem if I do not use '-wm' and '-multi' parameters or just
> > use 1024 with '-wm' and '-multi' except very slowness.
> >
> > I hope you can help me.
> >
> > Simen
> >
> >
> >
> > On Wed, Dec 24, 2014 at 6:50 PM, Even Rouault <
> even.rouault at spatialys.com>
> >
> > wrote:
> > > Le mercredi 24 décembre 2014 06:05:50, Simen Langseth a écrit :
> > > > What is the maximum '-wm' I can use with 64bit gdalwarp?
> > >
> > > Simen,
> > >
> > > Up to 9999 for 9999 MB. And if you want more, you have to specified the
> > > value
> > > in bytes instead of megabytes.
> > > But putting more warp memory will not necessarily need to more
> > > performance, especially if you mosaic many small images into a big one.
> > >
> > > See
> > >
> > >
> https://trac.osgeo.org/gdal/wiki/UserDocs/GdalWarp#WillincreasingRAMincre
> > > asethespeedofgdalwarp
> > >
> > > Even
> > >
> > > --
> > > Spatialys - Geospatial professional services
> > > http://www.spatialys.com
>
> --
> Spatialys - Geospatial professional services
> http://www.spatialys.com
>
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