When gdal_translate reads in a GeoTIFF .tif file and writes out a .ppm
file, the user receives a warning message saying that the
georeferencing metadata is not being copied into the output .ppm file,
and is being lost. When gdal_translate reads in a .tif file with TIFF
tag 700 XMP metadata, and TIFF tag 33723 IPTC metadata, and writes out
a .tif or .jp2 file, the user receives no warning that this metadata
is not being copied, and so I was surprised to later learn that the
XMP and IPTC metadata had been lost by gdal_translate.
I suggest that for GDAL 1.7 consideration be given to at least
notifying the user via a warning message that any input .tif file with
TIFF tag 700 XMP metadata, and TIFF tag 33723 IPTC metadata, and TIFF
tag 34665 EXIF metadata will lose that metadata and not have it copied
to the output file. Hopefully, a future GDAL release of gdal_translate
will preserve TIFF tag 700 XMP metadata, and TIFF tag 33723 IPTC
metadata, and the widely used TIFF tag 34665 EXIF metadata that
supports GPS metadata.
The Kakadu applications kdu_compress and kdu_expand, which are
available for free for Win32, Mac OS X, Linux, and Solaris, support
conversions between TIFF/GeoTIFF .tif files and JPEG2000/
GeoJPEG2000 .jp2 while preserving TIFF tag 700 XMP metadata, TIFF tag
33723 IPTC metadata, and TIFF tags 33550, 33922, 34264, 34735, 34736,
34737 georeferencing metadata.
Greg
On Sep 8, 2009, at 5:32 PM, Even Rouault wrote:
Selon Greg Coats <gregco...@mac.com>:
I have one .tif that has tag 700 XMP metadata, and has a tag 33723
IPTC metadata, but does not have tags 33550, 33922, 34264, 34735,
34736, 34737 georeferencing metadata. I have a second .tif that has
does not have tag 700 XMP metadata, nor does it have tag 33723 IPTC
metadata, but it does have 33550, 33922, 34264, 34735, 34736, 34737
georeferencing metadata. I want to add the tags that provide
georeferencing metadata in the second .tif, to the first .tif. As
shown below, I first tried using geotifcp, and then tried
gdal_translate, but while the resulting .tif does have the
georeferencing tags it originally lacked, the resulting .tif is
without the tag 700 XMP metadata, and without the tag 33723 IPTC
metadata that it originally had. How can georeferencing tags be added
to a .tif, withOUT removing preexisting tag 700 XMP metadata, and
withOUT removing preexisting tag IPTC 33723 metadata?
listgeo 18stj940125.tif > 18stj940125_listgeo.txt
geotifcp -s -r 1 -c none -f msb2lsb -g 18stj940125_listgeo.txt
tif_withXMP700_withIPTC33723_withoutGeo.tif
tif_withXMP700_withIPTC33723_withGeo.tif
Those 700 XMP and 33723 IPTC tags are not handled by the GTiff
driver neither in
read nor in write mode, so that explains why gdal_translate doesn't
copy them.
You could probably try the 'tiffset' utility to set them afterwards.
Or hack
geotifcp.c to add support for those 2 tags. The tags[] array looks
like an
interesting place where to hack that in.
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