XnView Software

I have approx 40,000 images, organised in a folder structure based on years (ie a folder for 1999, another for 1998 etc). The images have all been tagged in MS Photo Gallery,(PG is no longer supported and has lately begun behaving erratically, making tagging of more than one image at a time rather difficult). PG shows the tags in a tree structure eg

Animals
Dogs
Big dogs
Small dogs
Elephants
Black
White
Houses
Big
Tiny

etc

These have come across to XnView as

Animals/Dogs/Big dogs
Animals/Dogs/Small dogs
Animals/Elephants/Black
Animals/Elephants/White
Houses/Big
Houses/Tiny

etc

I should say that some tags have across as a tree structure, some have some across in the / separated format, and some have come across as both. I can't tell which have done what without going through each photo individually.

So I now have a huge number of tags, many hundreds of them.

Is the tree structure the normal way for XnView to display categories?

I want to delete the / separated categories, and keep the tree structure, but I will need to ensure that every / tag has a corresponding tree tag, and that any file tagged with a / tag is also tagged with the corresponding tree tag.

How do I easily organise or edit the categories?

Petr

You should first verify if all your tags are iptc keywords or xmp keywords. You can use also Exiftool tab in info pane for this step.

1) IPTC
Without hierarchy, list of keywords, often displayed with commas.
In iptc hierarchy, a separator character is used in a single string (Animals/Elephants/Black = 1 keyword) , and xnviewmp can read this.
Maybe, reading can be different if the string is built without spaces (Elephant/Black) or with a space (Elephant /Black) ?
If you used different methods or different softwares, it's possible that iptc keywords contains both hierarchized or not hierarchized keywords ...

2)XMP
In XMP, keywords are list-type without hierarchy for xmp-dc. (xmp-dc:subject)
When hierarchy is used, keywords are in xmp-lr (xmp-lr:subject) field.

Then, see settings metadata to choose a method for writing further keywords, or à new method if you want.
if you choose XMP, Xnviewmp will use xmp:dc:subject, and xmp:lr:hierarchicalSubject when writing xmp keywords.
If you choose IPTC, you can check "write hierarchical keywords"
(I think you should not add keywods in "Edit iptc/xmp" window, settings are in the least tab, and results may be different than using categories)

When you will modify categories, select a set of photos having a category, modify or unmark category, and unselect photos to make xnviewmp write new keywords into photos.
It's easier to create empty new categories before, and add photos in these categories..

... Select à new group of photos, and so on...

modified 2019/09/05