gdal_translate: tiff tags discarded with -co profile=Geotiff or Baseline

[quickstuff@…]

While converting tiff to tiff with gdal_translate, the creation options
PROFILE=GeoTIFF and PROFILE=BASELINE discard many existing tifftags and/or
prevent the addition of new ones.
It seems to affect baseline [informative, non-critical] tags such as
Resolutionunit, Imagedescription etc.
(Other baseline tags are unsupported whatever profile is invoked ; e.g. Artist
or Copyright)

[quickstuff@…]

Guess it is related to the lines :
    if( EQUAL(pszProfile,"GDALGeoTIFF") )
        GTiffDataset::WriteMetadata( poSrcDS, hTIFF, FALSE );
in geotiff.cpp

[warmerdam]

Mateusz,

I'd appreciate your looking into this. I think we need to call WriteMetadata() regardless of profile, but within WriteMetadata() we need to avoid writing custom TIFF metadata tags unless we are in the default GDALGeoTIFF profile.

Lets just do this in trunk since changes are fairly high risk, and need is modest. There should be a test suite test of some sort added to check profile operation in this regard, and perhaps some others.