[Gdal-dev] Reading Erdas Imagine Files Through GDAL 1.3.2

[Jingmu Yang]

warmerdam at pobox.com wrote:
> Jingmu Yang wrote:
>> I experience the performance downgrade after linking my application 
>> into GDAL
>> 1.3.2 to read (open) large (200MB) Erdas Imagine files.  It paused about
>> 20-30 seconds in calling GDALOpen.  But when I used the early GDAL 
>> release
>> (1.2.6) reading such files were very fast.  What happens with the latest
>> release of GDAL?
>
> Jingma,
>
> There have been a variety of improvements to the HFA driver in the 
> last year
> or two.  I suspect you are suffering from a lot of time being spent 
> turning
> a color table into a GDAL "Raster Attribute Table".  I recall having to
> do some serious work to improve the performance of this, though I'm not
> clear on whether that was before or after the GDAL 1.3.2 release. I'd
> suggest trying your gdalinfo, and the gdalinfo from a recent FWTools and
> see if the fwtools gdalinfo is nice and fast.  Alternatively, try 
> building
> from GDAL CVS source for comparison.
>
> If the problem persists with recent source then please file a bug and 
> make
> your file available somewhere for me to try with.
>
> Best regards,

I downloaded GDAL from CVS and rebuilt the library.  It is obviously 
that the performance problem for Erdas Imagine files has been solved.  
With the newly added class GDALRasterAttributeTable I can only use GDAL 
to retrieve the class names.

Thanks, Frank!

Regards,

Jingmu