[Gdal-dev] large image files

[Frank Warmerdam]

Steve Brooks wrote:
> Is there an image file format that will allow images greater than 4 Gig 
> in size
> 
> and work with gdal_merge.py?

Steve,

The PAux "raw" format should work for large files (as of GDAL 1.1.8) .

> I know kakadu will compress images bigger than 4 Gig but won’t work with
> 
> gdal_merge.py because the JP2KAKRasterBand::IWriteBlock isn’t implemented.
> 
>  
> 
> Are there any plans to implement JP2KAKRasterBand::IWriteBlock?
> 
>  
> 
> Would it be implemented similarly to JP2KAKCopyCreate but it would cache 
> tiles
> 
> until a complete row of tiles are available so that you can push and 
> entire line
> 
> to the compressor?
> 
>  
> 
>                 engines[c].push(lines[c],true);

Wow ... you have done some research.  There are a few issues:

  o gdal_merge.py writes out a whole input file at a time.  In the general
    case it would not be practical to cache these till complete scanlines are
    available.
  o the jpeg2000 output engines require the scanlines in order, and the
    bands need to be all available at the same time.  This make it unsuitable
    for the random access IWriteBlock() API.

Best regards,

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