GNOME Bugzilla – Bug 719522
gimp: DwC (Darwin Core) XMP metadata is not visible.
Last modified: 2014-02-09 15:05:54 UTC
Created attachment 263085 [details] Sample image with Darwin Core XMP metadata Open the sample DwC (Darwin Core) image in the Gimp. I tested with version 2.9.1 Go to Image > Image Metadata > XMP tab. DwC metadata is not visible. Some image viewers, such as eog & gthumb can see the DwC metadata in this image. Exiftool can read, edit and write DwC tags. Notes: Darwin Core (DwC) is a XMP metadata standard used for sharing biodiversity information. http://rs.tdwg.org/dwc/
I should add a bit more about DwC. It is specialized, but provides quite a lot of data that would otherwise be kept in a separate database rather then in the image metadata. The specific project I am lucky enough to be involved in is a wildlife camera trap project in the Amazon. (See the January 2013 National Geographic) They have 55,000 photos taken over the last several years. There are 170 specialized tags in the DwC standard, some highly relevant ones for this project are: -RecordBasisOfRecord - human observation? photo? -EventHabitat - jungle? swamp? -OccurrenceEstablishmentMeans - how did the animal get there, is it native to the area? introduced? -OccurrenceBehavior - what is the animal doing -OccurrenceIndividualCount - how many animals appear in the photo -OccurrenceIndividualID - if the animal can be uniquely identified -OccurrenceLifeStage - adult, juvenile -OccurrenceSex - male, female -TaxonScientificName - Scientific name of the animal -TaxonVernacularName - Common names for the animal Perhaps not very relevant to your typical photographer, but very important for researchers cataloging species and biodiversity. The full list of tags is here: http://rs.tdwg.org/dwc/terms/index.htm
Confirmed, seems to be a problem in gexiv2/exiv2. This is the output while loading the file: ** (file-jpeg:9194): WARNING **: Unsupported time format and then a gazillion of: ** (lt-gimp-2.9:9161): WARNING **: No namespace info available for XMP prefix `dwc'
*** Bug 719623 has been marked as a duplicate of this bug. ***
Darwin Core is being discussed on the Exiv2 dev's forum: http://dev.exiv2.org/boards/3/topics/1675 At this point I don't believe this is a gexiv2 per se, rather a problem inside of Exiv2. I've filed a formal ticket for DwC support at http://dev.exiv2.org/issues/937
Agreed that changes are needed inside exiv2 to provide full read/write support for DwC and I've added some details to that ticket. But, I understand that exiv2 can pass throuh XMP metadata that it does not have the schema for. For example, gthumb can display the raw DwC metadata and there is a patch to allow digikam to display it as well: https://bugs.kde.org/show_bug.cgi?id=328018
I can report that support for DwC in exiv2 is coming along, I have write support working, it just does not display the results as nicely as I would like, so I have some more work to do on it. http://dev.exiv2.org/issues/937#note-19
Well, my exiv2 work is not coming along as well as I thought. It looks like no one has implemented a XMP namespace using a nested structure in exiv2 and DwC is a nested namespace. Other nested namespaces, such as IPTC Core, are implemented with a flat structure in exiv2 while they are implemented as nested namespaces in exiftool. Perhaps a real coder (unlike myself) could take a look and figure out how to implement nested namespaces in exiv2?
My patch to exiv2 is working for me, but I still cannot see any DwC XMP metadata in Shotwell or in the Gimp. I'm not enough of "a seasoned developer" to figure out if gexiv2 in it's current form is stripping out the DwC XMP fields or if the user apps are doing that. Is there a test command or script that I could run that would show what gexiv2 is doing? PS: The patch to exiv2 can be found here: http://dev.exiv2.org/issues/937 And a PPA with a build of exiv2 + DwC is here: https://launchpad.net/~alan-pater/+archive/dwc
Alan, Shotwell doesn't have any facilities today for displaying all Exiv2 metadata in the UI. I can't speak for GIMP, I haven't tried their latest builds. What I have done is included a new utility command-line tool in gexiv2 that should be able to help you. It's in commit 7d687ba in master. To use it, you need to pull the latest and then: $ ./autogen.sh $ ./configure --enable-tests $ make $ make tests This will build test/gexiv2-dump. (Note that you must have a recent version of Vala installed to build it.) You can then run: $ test/gexiv2-dump image.jpg This will dump the image file's Exiv2 tags and their interpreted string values to stdout. I tried it with the DwC-SampleImage.jpg and received what looked to be proper output, including Darwin Core tags, but I suspect without your patch the DwC tags are not being properly listed/handled. For example, I'm seeing tags like this: Xmp.dwc.dctermsLocation/dwc:continent Since the output is so long, I've attached it as a file. Also, it prints this warning when it starts: ** (process:10130): WARNING **: Unsupported time format I'm not sure at this time where this is coming from, but don't think it's an immediate impediment to your testing.
Created attachment 268108 [details] gexiv2-dump output of DwC-SampleImage.jpg
Great, thanks a lot Jim! I'll test with my patch to make sure, but it looks like gexiv2 is seeing all the DwC tags correctly. The long, nested names are how things look through exiv2, even with my patch, so that is not an error on the part of gexiv2, it's just how nested tags work with exiv2.
So gexiv2 can see DwC metadata regardless, just like exiv2 can. So with my patch to exiv2 the question becomes: Can apps or scripts write DwC tags through gexiv2? Is there some basic script laying around that can test writing tags?
Jim, great news. gexiv2 does not have any problem reading and writing DwC metadata. I tested with the Photini metadata editor. I just changed a couple of it's writable tags to DwC ones and successfully wrote them to a test image. This was with exiv2 0.23 + my DwC patch & the unmodified gexiv2 that comes with Ubuntu 14.04 (Trusty).
Why is this bug back with GIMP now? I thought gexiv2 reads/writes it nicely now. GIMP adds nothing on top of gevix2.
Michael, I guess the question is, does GIMP display the DwC metadata? If GIMP is merely listing all tags/values it finds in the image, then I think this ticket is closed. There's a sample image with a lot of DwC at bug #723794 for testing. Alan, are there any plans to document DwC on Exiv2's tag reference, i.e. http://exiv2.org/metadata.html? I've ticketed the "Unsupported time format" bug at bug #723794. At this point I don't think this is an impediment to closing this ticket.
Yes GIMP simply lists all tags it gets from gexiv2. And even if we should add special treatment for certain tags or tag groups, I guess we will always have a raw view that shows them all. Closing as FIXED.
Oh and thanks for taking care of this :)
Jim, my patch to exiv2 includes the documentation for the DwC tags. That should show up on the exiv2 site when 0.25 is released, assuming my patch makes it in that release. Michael, you're right, GIMP is now showing all the DwC tags from the sample image. Thanks guys!