XnView Software

Being relatively new to both image metadata and XnviewMP, I was and still am overwhelmed by the number of standards involved.
Over the past few years I have been trying to embed image metadata in at least some of the images I have collected as part of my genealogy research.
During this time, I have tried several applications (both free, built-into the OS & even commercial) which seemed to promise the ability to add, edit and search for the intended metadata.

Unfortunately, few applications seem to use the same set of data labels in their presentation to the user for fields saved in various metadata fields - an issue which has cost me untold hours and frustration.
Because, by now, I have decided to stick with XnviewMP for this work, I am very curious to find out which of the manifold data fields from the various still image metadata standards I can access from within XnviewMP and how. Presumably, if an image contains a specific data field with some data, XnviewMP can read and display it.
What is not clear to me whether I can decide to add a label/data pair for a standard field not in the original file and how.
Because I am very new, I may well have either missed or misunderstood some of the many documents I have read and videos I have watched. In that case please point me in the right direction.
Even better, for me, would be if there was a list of the labels used within XnviewMP and the corresponding standard data field(s) defined by the standards involved.
This is very important for me, because, over time, I am sure that some of the data I have added is either not complete or not entirely consistent between related image classes (because some of the work was, or might have been done, using different applications) and I need to make sure I am comparing apples with apples - or corresponding standard data pairs of label and content.

Hi,
I do not have enough time to answer in detail today, but here is a link to the MWG metadata, it is a recommendation to group the fields exif, iptc, xmp whenever possible. We therefore find the equivalences.
https://www.sno.phy.queensu.ca/~phil/ex ... s/MWG.html

Personally, I use IPTC + XMP, keywords, description, city. it's already a lot of metadata and a lot of work.

With XnViewMp,
For keywords, I use "categories" that can create iptc:keywords , xmp-dc:subject and xmp-lr:hierarchicalkeywords
For Description and City, I use Edit iptc/xmp window, that creates :IPTC:Caption-Abstract and XMP-dc:Description , IPTC:City and XMP-photoshop:City
I think it's a sufficient set for my purpose, I don't need more exotic data...

Once you have chosen settings , and you are sure they are ok, you will be able to update some metadata with xnviewmp (copying iptc into xmp or or other things like that)
At any time, you can look into "exftool" tab, in Info panel, to check all metadata .

Thank you very much for your comments. I found them very helpful.

Just prior to posting my question, I had looked through the XnViewMp forum for prior discussions and answers and ended up on your site.
Even though my French is pretty rusty, Google Translate did a marvelous job and I very much appreciated the content of it. Kudos.

As far as my current 'problem' goes, perhaps I am a bit too careful, but I agree with your assessment of using the fields you mentioned and I have used categories, especially hierarchical categories a fair bit in my latest work.
For myself, aside from subject and location data, the most important aspects are personal data such as names, ages, event dates. And the data MUST be searchable.

The next step for myself is now to test the software I have decided to use - mostly XnViewMP & Exiftool - and then set up a work flow which gives me what I need without being so cumbersome as to be 'too much effort'
My big concern is to have the data relatively consistent from image to image because without it, searching the data is way to time consuming and too much dependent on a very good memory, which in effect makes searching next to impossible. This may well mean that I have to investigate the batch facilities.