[gdal-dev] slow raster (large GDALRasterAttributeTable?)

[Frank Warmerdam]

bartvde at osgis.nl wrote:
> Hi list,
> 
> I've got a tiff file of 28 Mb and it is really slow, so I am assuming the
> classification gets applied on the fly or something like that.
> 
> If I do a gdalinfo I get a huge list of STATISTICS_HISTOBINVALUES
> 
>   Metadata:
>     STATISTICS_MINIMUM=-5838
>     STATISTICS_MAXIMUM=4225
>     STATISTICS_MEAN=-1010.4585191036
>     STATISTICS_MEDIAN=-212
>     STATISTICS_MODE=1
>     STATISTICS_STDDEV=1833.0113850333
>     LAYER_TYPE=athematic
>     STATISTICS_HISTOBINVALUES=1|1|1|1|1|1|1|1|1|1|1|2|1|2|1|1|1|2|1|1|1|1.......
> 
> Also, the GDALRasterAttributeTable has 9150 rows. Don't know if this is
> related.
> 
> Any ideas on how to speed this up? I tried to write it out to a new
> GeoTiff or MrSID file, but somehow all this info is preserved, and the
> slowness continues.

Bart,

Could you provide the dataset?  I'd be interested in reviewing the
performance of the raster attribute table logic with an eye towards
optimizing it.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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