[Gdal-dev] GML headers for JPEG2000 files

[Frank Warmerdam]

On 5/17/05, Armin Burger <armin.burger at gmx.net> wrote:
> Frank,
> 
> thanks for the quick reply. I would be mainly interested in the coordinate and georeference info in the Jp2 files. But of course, if other metadata could be added then the better.
> 
> At work we are currently using ER Mapper to convert files to ECW but are thinking to move to Jp2 because of better and standardized support of metadata. But the ER Mapper converter is not really transparent how to specify metadata, currently it seems to work just fine with a few standard projections like UTM. So we were thinking having a look at GDAL to use it instead.

Armin,

The ECW SDK's support for coordinate systems is pretty decent for 
EPSG coordinate systems, or other common combinations.  But it does
not extend in an obvious way to user defined CRSes. 

> How is the metadata defined in the CVS version of GDAL, via a separate file? Do you have any compiled version of the modified ECW SDK for Linux like the one from January? I was successful compiling the SDK but then could not compile GDAL with that one. It worked fine though with your pre-compiled version from January.

The GML metadata for jpeg2000 files is embedded in the JPEG2000
file in an xml box.  Is that the question?  Or how is the informatin passed
to gdal_translate to encode?  There are many options including on the
commandline or embedded in the source file. 
 
I hope to issue new FWTools builds with the new gml-in-jpeg2000
support in a nearly final form soon.  So you might consider messing
with that.  I will note that the GML-in-JPEG2000 specification is not
yet finalized and so it might be premature to make yourself very
dependent on it.  But it is sensible to look forward to this as a next
generation approach.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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and watch the world go round - Rush    | Geospatial Programmer for Rent