Repeatable Tags - Defined Where & Use of Panel vs. Template

[PandDLong]

In using repeatable tags I have come across a couple of situations that seem odd - at first - but with more experimenting seem consistent and likely "as intended".

1. What is a repeatable tag is defined by exiftool which would be as documented on their site under 'Exiftool Tag Names'.

2. When updating a repeatable tag:
      a. Using a metadata template - duplicates are removed
      b. Using a metadata panel - no removal of values is done

3. When adding a 'null' value into a list:
      a. Using a metadata template - it is removed
      b. Using a metadata panel - it is removed only on writeback


Is the above correct - and thus I can expect that behaviour consistently (or have I done something strange)?


Michael

[Mario]

When do you produce duplicates. And with "null value" you do that how?
IMatch only de-duplicates keywords, AFAIK. But metadata templates are complex, and there are options you can set (e.g. merge) which impact the outcome. I would need more details.

Usually setting repeatable tags is not something a user does often. When do you need this?

[PandDLong]

When do you produce duplicates. And with "null value" you do that how?
IMatch only de-duplicates keywords, AFAIK. But metadata templates are complex, and there are options you can set (e.g. merge) which impact the outcome. I would need more details.

Usually setting repeatable tags is not something a user does often. When do you need this?

I use repeatable tags for a few things - they are great for anything you want to retain as a list.  There are the specific variable functions which are useful at times.  The best value for me is how they work with a tag-based data driven category - each entry in the list shows up in the category properly but if I use a regular tag for a list, the category result is not as useful.  For example a tag with two entries "A;B"

• Repeatable tag:  in the category there is an A and a B and they show up with other files that have that value
• Regular tag: in the category there is an "A;B" which is listed differently from files with just "A" or "B"

A couple of examples of my use, in addition to keywords and Person in Image (which iMatch populates) are tags I use for:

• People details (pulling data from the People database and storing it in the metadata)
• Sources for More Information (a PLUS Custom tag)

I also intend to use a repeatable tag for capturing animal species and breeds.

I could use keywords for these but I like to keep my thesaurus a managable size and relatively fixed.  Adding everything as a keyword would slow down entry as I use the "key ahead" feature a lot and finding the information in the keyword field could be like the "needle in a haystack".  I have found having this information in specific tags is more intuitive and much quicker to see at a glance the values for a particular photo for a given tag (and I find it easier in any processing by using hasvalue/default type functions).

Bottom-line - I think repeatable tags are fabulous and I love how iMatch is able to use them including the thesaurus!


I have done pretty extensive testing - including the merge outcome in a MDT - so I think the conclusions are valid.


Now - why would I have duplicates and nulls?  The most common scenario is when it is part of a repeated structure - but that is a bit of a different topic and I will post specifically on that - but I believe it is inter-related.

• Duplicates can occur when People Details are not unique (and both people are in the same photo) - short name is the obvious situation. 
• Nulls can occur when someone is missing the details (and just the list separator is entered).

I posted this because I was driving myself a little crazy when sometimes a tag held duplicates/nulls and sometimes it didn't.  Hence all the testing and my conclusion that panels and templates treat these tags a little differently.  Not that it is wrong since it seems entirely consistent - it fits into the Good-to-Know category so the outcome matches the expectations when I update metadata.


As a side note, from all the testing, I identified which repeatable tag functions work (and which don't) for regular tags that look like a list (eg. one; two; three).  Would that be of interest to post?


Michael





 
   
   

[PandDLong]

A correction and one addition:

1. A null value in a list is removed by the panel when the change is saved  (ignore my comment on it being done on write-back) thus metadata template and panel handle them the same.

2.  The most popular repeatable tag - Keywords - does act the same way.  In a metadata panel, duplicates are not removed, but they are when applying a template and they are by the Keywords Panel.

Michael