shotwell

Hey Adam,

I did hear back from Gilles (the digiKam maintainer). Insofar as I could determine, there is no "standard" XMP tag for hierarchical keyword data, whereby "standard" I mean it's part of the Dublin Core or some other specification produced by a vendor-neutral committee. I proposed to Gilles that we create a new field specification for hierarchical tag information and publish it to freedesktop.org. Gilles replied that hierarchical keyword handling was already problematic enough and that they very much wanted to keep it within the digiKam namespace.

We could publish our own standard; others (especially in the open source world) might even follow.

It's worth noting, however, that there is a de facto standard: the Adobe Lightroom xmp.lr.hierarchicalSubject field. Actually, since Adobe is the steward of the XMP spec, it might not even be de facto. Almost all photos that I've found in the wild that have any hierarchical subject information associated with them have this field populated. We read from this field today. Unfortunately, we can't write to it without hacking around an exiv2 problem in GExiv2. The ticket for that is here: #3950

Lucas Beeler wrote:

bq.

 It's worth noting, however, that there is a de facto standard: the Adobe Lightroom xmp.lr.hierarchicalSubject field. Actually, since Adobe is the steward of the XMP spec, it might not even be de facto. Almost all photos that I've found in the wild that have any hierarchical subject information associated with them have this field populated. We read from this field today. Unfortunately, we can't write to it without hacking around an exiv2 problem in GExiv2. The ticket for that is here: #3950  

I see in the mwg guidelines (page 62) that they suggest to use the prefix mwg-kw for keyword, and specifically 'mwg-kw:Hierarchy' for hierarchical keywords. Am I missing something or this should be the way to go? http://www.metadataworkinggroup.org/specs/

On a side note, I'd like to have most of the equivalent fields filled up when tagging, for compatibility purposes.

-pt

On a side note, I'd like to have most of the equivalent fields filled up when tagging, for compatibility purposes.

Agreed. We especially need to write to Xmp.lr.hierarchicalSubject because it does appear to be the de facto standard in place now.