[gdal-dev] gdal_translate - ECW format and non-UTM projections

[Jean-Claude Repetto]

On 06/08/11 19:36, Armin Burger wrote:
> thanks for pointing me to the ECW definitions. My main problem are
> currently the missing ETRS89/GRS80 definitions for several pan-European
> projections that are missing. Some national projections I need I could
> already identify and I will try them. If a projection is missing can I
> add it and GDAL will try to use it when reading and creating ECW files?
> Regarding the datums I guess I will be limited to the ones available in
> this list an understood by the ECW library, right?

No, you can add datums and projections to the ecw_cs.wkt file, and GDAL 
will recognize them.
Then, you can submit a patch, like I did a few months ago to add french 
datums and projections (see <http://trac.osgeo.org/gdal/ticket/3868>).
>
> Is there a way to update an ECW file adding this type of information via
> GDAL API functions? I know there was a Windows GUI tool from ER Mapper
> some years a go that could modify some kind of ECW header, but I would
> need to run this on at least several 100's of files, so a manual
> approach is not feasible. Or do I need to re-create all ECW's and add
> the projection options?

The "ECW Header Editor" is still available from Erdas : 
<http://erdas.com/products/ERDASAPOLLO/ERDASAPOLLOEssentials-ImageWebServer/Downloads.aspx>
ER Mapper was also providing a command line tool that you could use in a 
script, but I don't know if it is still available. (The URL was 
<http://www.ermapper.com.au/downloads/ecwheader.zip> , but it is not 
working at this time). If not, you can try a small command line utility 
I wrote a few years ago (<http://jrepetto.free.fr/ecwhed/>), but you'll 
have to compile it for Windows.

Jean-Claude