In short: Use keywords when you want to store the data in your image files. Use categories in addition to organize your image collection.
To add edit keywords, use the
Keyword Panel. It has sophisticated features to manage keywords, integrates the thesaurus etc.
See the video tutorials for the Keyword Panel here: https://www.photools.com/imatch-learning-center/
When you modify keywords, they will be written back to the image file automatically.
The special
@Keywords category hierarchy is automatically filled from the keywords in your files, providing a convenient way to quickly see/select files by their keywords. @Keywords also offers some unique keyword-related features. Renaming keywords, adding/changing keywords by drag and drop, changing entire keyword hierarchies etc. But if you have seen all the video tutorials, you know about these already.
https://www.photools.com/help/imatch/#cat_keywords.htm
IMatch categories are a concept that is unrelated to metadata. Categories are stored inside your database and can be used for all file formats, whether the file format supports metadata or not. Moving files between categories is very fast, and you can quickly re-arrange your category hierarchy by drag and drop. Formula-driven categories and data-driven categories add a lot of power to quickly organize even very large image collections.
QuoteWhere|Country|State|City|location - written to/read from IPTC4xmp:Location created
Who|Family|Name - written to/read from IPTC4xmp:Person Shown in Image
What|Event|EventName - written to/read from IPTC4xmp:Event
Style|StyleOfImage - written to/read from IPTC4xmp:Genre
TakenBy|Name - written to/read from IPTC4xmp:Creator
This is not possible. To edit this type of metadata, use the
Metadata Panel.
You can use data-driven categories to map this information back into your category hierarchy when you need that. But you cannot fill metadata from individual categories (e.g. assigning a file to a category named Style|StyleOfImage and then making IMatch to copy that into the IPTC4xmp:Genre tag. Such a functionality does not exist in IMatch. If you add the value ""Portrait" to IPTC4xmp:Genre and you create a data-driven category for that tag, IMatch will show your files in that category hierarchy by their value.
If you think that this would be useful for other users, feel free to add a feature request in the feature request (https://www.photools.com/community/index.php?board=12.0) board.
If you really have to, you can use a
Metadata Template to copy category information for selected categories/levels into metadata fields (which would be the reverse operation) but that's usually only needed for very specific workflows. It's much easier to use the Metadata Panel to add such information.
I think you should make yourself aquatinted with the
IMatch Universal Thesaurus. This is the feature for setting up (hierarchical) controlled vocabularies for keywords and other tags of interest.
https://www.photools.com/help/imatch/#thes_basics.htm
The contents of the thesaurus can be accessed in the Keyword Panel (for keywords) and in the Metadata Panel for all other tags.