[Gdal-dev] gdal with ECW JPEG 2000 SDK v3.1

[Frank Warmerdam]

On Thu, 17 Mar 2005 15:13:08 +0800, Tom Lynch <tflynch at gmail.com> wrote:
> I previously responded to Brent off list on this topic, but for the
> benefit of anyone else wishing to enable unlimited compression to ECW
> and JPEG 2000 via GDAL and the ECW JPEG 2000 SDK, these are the
> specific changes that are necessary in the GDAL source code (both are
> calls to CNCSFile::SetKeySize):
> 
> 1. Changes to ecwcreatecopy.cpp:
> 
> -----------------------------------------
> CPLErr GDALECWCompressor::Initialize(
>     const char *pszFilename, char **papszOptions,
>     int nXSize, int nYSize, int nBands,
>     GDALDataType eType,
>     const char *pszWKT, double *padfGeoTransform,
>     int bIsJPEG2000 )
> 
> {
>     SetKeySize();

Folks, 

I have changed the GDAL code in CVS (but after the 1.2.6 release) 
so that this call is made if the ECW_LARGE_OK configuration option
is set to YES.  Configuration options can be set at the commandline
using the --config option (eg. --config ECW_LARGE_OK YES),
as environment variables or at the API level by calling 
CPLSetConfigOption().   Please only do this if you are complying
with the appropriate licensing requirements. 

> 2. Changes to ecwdataset.cpp:
> 
> -----------------------------------------
> 
> GDALDataset *ECWDataset::Open( GDALOpenInfo * poOpenInfo )
> 
> <snip>
> 
> /* -------------------------------------------------------------------- */
> /*      Open the client interface.                                      */
> /* -------------------------------------------------------------------- */
>     if( poFileView == NULL )
>     {
>         poFileView = new CNCSFile();
>         poFileView->SetKeySize();
> -----------------------------------------
> 
> These two lines are needed in addition to linking with NCSEcwCu.lib
> (or libNCSEcwCu.o if you're building the SDK from source on *NIX) for
> unlimited compression.

Tom - what does this do?  Is SetKeySize() needed to *read* large
ECW files? 

Best regards,
-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent