[gdal-dev] ECW writing (was GTiff optimisation)

[Jean-Claude Repetto]

On 09/22/11 19:03, Even Rouault wrote:
>>
>> - gdal_edit reports no error when the parameters are wrong :
>> $ gdal_edit.py -mo KJHJKHJKHJ=GKFLLLMM France.ecw
>
> I see nothing wrong here. It is perfectly valid to assign GKFLLLMM to
> KJHJKHJKHJ metadata item. gdal_edit.py is meant as being generic, so if the
> driver doesn't understand natively the metadata item, this will generally
> fallback to storage in .aux.xml file if the driver supports the PAM mechanism.

At least, gdal_translate displays a warning :

$ gdal_translate -of ECW -co "KJHJ=KJKJ" -a_srs epsg:27572 test.jpg test.ecw
Input file size is 480, 272
Warning 6: Driver ECW does not support KJHJ creation option
0...10...20...30...40...50...60...70...80...90...100 - done.

>
>>
>> - It would be nice if gdal_edit could display the current parameters
>> when called without options.
>
> Well, gdalinfo does already do that, so I don't think this is really
> necessary.

I don't agree, gdalinfo gives some informations, but not the name of the 
datum and the name of the projection. And a lot of ECW projections or 
datums are not supported in GDAL.

Example :

$ gdal_translate -of ECW -co "DATUM=BELG72" -co "PROJ=LM2BELG72" -a_ullr 
100000 5000000 800000 4000000 test.jpg test.ecw
Input file size is 480, 272
0...10...20...30...40...50...60...70...80...90...100 - done.

$ gdalinfo test.ecw
Driver: ECW/ERDAS Compressed Wavelets (SDK 3.x)
Files: test.ecw
Size is 480, 272
Coordinate System is `'

When gdalinfo displays "Coordinate System is `'", how do you know if 
this is because the file is not georeferenced, or because GDAL does not 
know the projection ?


Jean-Claude