[gdal-dev] Help requested: Concurrent read of a GeoTiff

[Even Rouault]

On jeudi 16 mars 2017 18:45:03 CET Grégory Bataille wrote:
> Does that mean a different vrt file or simply reopen the file to create a
> gdal object in each process. Because I'm reopening the vrt file in each
> thread

Ah, that must be issue of
http://gdal.org/gdal_vrttut.html#gdal_vrttut_mt

Try defining
gdal.SetConfigOption('VRT_SHARED_SOURCE', '0')
before opening the VRTs

> 
> 
> On Thu, 16 Mar 2017 at 17:23, Even Rouault <even.rouault at spatialys.com>
> 
> wrote:
> > On jeudi 16 mars 2017 17:16:20 CET Grégory Bataille wrote:
> > > Hello all,
> > > 
> > > 
> > > 
> > > Reaching out to the community caused I have failed for the past few
> > > days.
> > > 
> > > 
> > > 
> > > *short version*, I'm trying to multithread the gdal2tiles utility, and
> > 
> > I'm
> > 
> > > getting this
> > > 
> > > 
> > > 
> > > Generating Base Tiles:
> > > 
> > > ERROR 1: LZWDecode:Wrong length of decoded string: data probably
> > 
> > corrupted
> > 
> > > at scanline 256
> > > 
> > > ERROR 1: TIFFReadEncodedTile() failed.
> > > 
> > > ERROR 1:
> > > 
> > > /Users/gbataille/Downloads/Project_58704_transparent_mosaic_group1.tif,
> > > 
> > > band 1: IReadBlock failed at X offset 1, Y offset 0
> > > 
> > > ERROR 1: GetBlockRef failed at X block offset 1, Y block offset 0
> > > 
> > > ERROR 1: gba.vrt, band 1: IReadBlock failed at X offset 0, Y offset 0
> > > 
> > > 
> > > 
> > > Any idea?
> > 
> > Yes, you need one dataset object per thread . Dataset objects cannot be
> > used simultaneously from several threads.
> > 
> > 
> > 
> > Even
> > 
> > 
> > 
> > 
> > 
> > --
> > 
> > Spatialys - Geospatial professional services
> > 
> > http://www.spatialys.com


-- 
Spatialys - Geospatial professional services
http://www.spatialys.com
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