Thanks for your question and for the details on how you are using IPTC to categorize your media.
You wrote “I can’t find a mapping rule to create this output. Do you have an idea?” You can use a content template for this purpose. The taxonomy mapping rules accept a comma-separated list of terms, so you can enter this template in the “EXIF/Template” text box of the mapping rule for the Att. Categories taxonomy:
template:([+iptc:2#015+] [+iptc:2#040+])(,[+iptc:2#015+] [+iptc:2#020+])
Note, however, that this rule creates two “flat” terms in the root level of the Att. Categories taxonomy. If you want “01” as a separate parent term and “Main Category” and “Sub Category” as child terms you will need a different approach. MLA has an example plugin that lets you code multi=level hierarchical terms. You can find details in this earlier topic:
Att. Categories Advanced Mapping
Once the example plugin is installed and active, the content template for your application would be something like:
template:([+iptc:2#015+]/[+iptc:2#040+])(,[+iptc:2#015+]/[+iptc:2#020+])
In the above template the spaces are replaced with slashes (‘/’) to separate the terms into parent and child terms. The example plugin has a Documentation tab that explains everything.
You wrote “I could see that the fields 2#015, 2#020 (IPTC IIM) have been depreciated. The deprecated warning applies to using these fields in a “newsroom” application. I am confident that the fields will be usable indefinitely just because so many existing image files contain them.
You wrote “I found something about subject newscodes“. It looks like this is a reference to IPTC efforts to create controlled vocabularlies for newsroom applications. I found this information on the IPTC web site:
IPTC creates and maintains sets of concepts – called controlled vocabularies or taxonomies – to be assigned as metadata values to news objects like text, photographs, graphics, audio and video files and streams. This allows for a consistent coding of news metadata across news providers and over the course of time – that’s the reason why we call them IPTC NewsCodes.
The Subject Codes is the original IPTC subject taxonomy, with a focus on text. It consists of about 1,400 terms structured into 3 levels.
IPTC is not actively maintaining the Subject Codes taxonomy, and would recommend that news organisations adopt its successor, the Media Topics vocabulary.
Media Topics is a constantly updated taxonomy of over 1,200 terms with a focus on categorising text. Originally based on the IPTC Subject Codes taxonomy, the Media Topics taxonomy was first released in 2010 and is updated at least once a year.
I haven’t looked into how these terms are stored in the IPTC fields. If you find a good application for them, post an update and share your findings.
I am marking this topic resolved, but please update it if you have problems or further questions about the content template suggestions. Thanks for your continued interest in the plugin.