How to describe derived work on CC BY-SA 3.0 using RDFa

Let's say I have an image /img/fox.svg which is derived work, based on https://commons.wikimedia.org/wiki/Vulpes_vulpes#/media/File:Captive_red_foxes.JPG which is shared CC BY-SA 3.0 with author GDallimore (https://commons.wikimedia.org/wiki/User:GDallimore).

I'd like to properly attribute this image using RDFa, but I am just starting and details elude me.

I tried to start with Dublin Core like this:

<span prefix="dcterms: http://purl.org/dc/terms/ dctype: http://purl.org/dc/dcmitype/">
    <span resource="/img/fox.svg" typeof="dctype:Image">
        <a property="dcterms:source" href="https://commons.wikimedia.org/wiki/Vulpes_vulpes#/media/File:Captive_red_foxes.JPG">
        </a>
    </span>
</span>

and maybe extend it to

    <span prefix="dcterms: http://purl.org/dc/terms/ dctype: http://purl.org/dc/dcmitype/ rdfa: http://www.w3.org/ns/rdfa#">
        <span resource="/img/fox.svg" typeof="dctype:Image">
            <a property="dcterms:source" href="https://commons.wikimedia.org/wiki/Vulpes_vulpes#/media/File:Captive_red_foxes.JPG">
            </a>
            <a property="http://creativecommons.org/ns#license" href="https://creativecommons.org/licenses/by-sa/3.0/">CC BY-SA 3.0</a>
        </span>
        <a about="https://commons.wikimedia.org/wiki/Vulpes_vulpes#/media/File:Captive_red_foxes.JPG"
           property="http://creativecommons.org/ns#license" href="https://creativecommons.org/licenses/by-sa/3.0/">CC BY-SA 3.0</a>
        <a about="https://commons.wikimedia.org/wiki/Vulpes_vulpes#/media/File:Captive_red_foxes.JPG" property="dcterms:creator"
           href="https://commons.wikimedia.org/wiki/User:GDallimore">GDallimore</a>
    </span>

which results in

@prefix dcterms: <http://purl.org/dc/terms/> .
@prefix dctype: <http://purl.org/dc/dcmitype/> .
@prefix rdfa: <http://www.w3.org/ns/rdfa#> .
@prefix cc: <http://creativecommons.org/ns#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix schema: <http://schema.org/> .
@prefix xml: <http://www.w3.org/XML/1998/namespace> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

</img/fox.svg> a dctype:Image ;
    dcterms:source <https://commons.wikimedia.org/wiki/Vulpes_vulpes#/media/File:Captive_red_foxes.JPG> .

<https://commons.wikimedia.org/wiki/Vulpes_vulpes#/media/File:Captive_red_foxes.JPG> cc:license <https://creativecommons.org/licenses/by-sa/3.0/> ;
    dcterms: <https://commons.wikimedia.org/wiki/User:GDallimore> ;
    schema:creator <https://commons.wikimedia.org/wiki/User:GDallimore> .

but got stuck beyond this point ‒ it feel very repetitive and I cannot really say if it makes sense.

Solution

No, it doesn't entirely make sense! Triples like this are wrong:

<https://commons.wikimedia.org/wiki/Vulpes_vulpes#/media/File:Captive_red_foxes.JPG> 
    dcterms: <https://commons.wikimedia.org/wiki/User:GDallimore> ;

I think you are missing a particular property for your use of dcterms:.

But, otherwise, you are doing fine. How about just this:

</img/fox.svg> a dctype:Image ;
    dcterms:source <https://commons.wikimedia.org/wiki/Vulpes_vulpes#/media/File:Captive_red_foxes.JPG> .


<https://commons.wikimedia.org/wiki/Vulpes_vulpes#/media/File:Captive_red_foxes.JPG> 
    cc:license <https://creativecommons.org/licenses/by-sa/3.0/> ;
    dcterms:creator <https://commons.wikimedia.org/wiki/User:GDallimore> .

You don't need both schema.org and Dublin Core properties to describe what's going on here. Just pick the set you think most appropriate. They have overlap.