[gdal-dev] Error when trying to compress a TIFF file

[Hanlie Pretorius]

Hi Even,

Thanks, the gdaldo command made a huge difference to the speed with
which QGIS works with the raster.

The image looks a bit shoddy, though, even when zoomed out. It
improved when I set the quality to 100 and the file is still a tenth
of the original size.

Would it help to create more levels in the overview and, if so, at
which end should I add the levels?

Hanlie

2014-08-26 16:25 MGT+02:00, Even Rouault <even.rouault at spatialys.com>:
> Hanlie,
>
> The warning "VRTSourceRasterBand::iRatserIO() called recursively on the
> same
> band" is bug http://trac.osgeo.org/gdal/ticket/5468
> It is due to the statistics computation on the intermediate VRT file
> (implementation detail), but shouldn't influence on the image itself
> You can run afterward "gdalinfo -stats Test_8bit_JPEG_Compr.TIF" to compute
> statistics on the result TIF.
>
> The slowness in QGIS is not surprising since JPEG takes time to
> decompressing,
> especially for big images, that are not tiled and have no overviews. What
> could
> help is to add -co TILED=YES on the gdal_translate command line.
> And then run "gdaladdo --config COMPRESS_OVERVIEW JPEG
> Test_8bit_JPEG_Compr.TIF
> 2 4 8 16" on the result to create overviews.
>
> Even
>