Semantically correct way to add a copyright notice into a svg file?

Question

I want to add a copyright notice in my svg files and it should be only "hidden" text and no watermark. This is no real protection, because if you open a svg file with a text editor you can edit everything and delete the copyright. But I think this would be a simple and great way to show, who has made the file and a possible chance to find unlicensed graphics if there is some hidden information and if you are looking for it you can easily find it.

My main question is: how should the copyright text be put into the file?

• <title> element is for accessibility purposes, some user agents display the title element as a tooltip.
• <desc> element generally improves accessibility and you should describe what a user would see.
• ugly way: a text element with inline CSS to hide it. Don't even think about this! :)
• <!--Copyright info here--> could be also a simple solution.
• <metadata>: this would the best way but I did not find a detailed definition and which child elements could live inside. Also https://developer.mozilla.org/en-US/DOM/SVGMetadataElement gives a 404. Under https://www.w3.org/TR/SVG/struct.html#MetadataElement we can find more details. But is RDF really necessary?

I think a <metadata> element is the right place, but which child elements should be used and is just RDF the way to go?

Pressroom

I agree that <metadata> is where this kind of info should go. I think the XML Schema allows you to just use text inside this element without additinal markup, be it RDF or anything else. But for accessibility reasons, I think it's a good idea to use some standardized markup for making explicit that you are encoding copyright information. – Corked

"But is RDF really necessary?" -- Sounds like you think this would be a problem … why? – Matronna

I don't think it is a problem to use RDF, but I think it is a little bit overruled for "just" a copyright info... @unor, which RDF property should I use? – Pressroom

Do note that if unor's answer helped you, you can vote on it by clicking the arrows or accept it as correct by clicking the checkmark. – Disbelief

Answer 1

I think the metadata element is the correct choice here. It has to contain XML, but it doesn’t have to be a RDF serialization (e.g., RDF/XML).

But I think it makes sense to use RDF here, because that’s exactly RDF’s job (providing metadata about resources, like SVG documents), and there is probably no other XML-based metadata language that has greater reach / better support.

A simple RDF statement (in RDF/XML) could look like this:

<metadata>
  <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:schema="http://schema.org/">
    <rdf:Description rdf:about="http://example.com/my-svg-file.svg">
      <schema:license rdf:resource="https://creativecommons.org/licenses/by-sa/4.0/"/>
    </rdf:Description>
  </rdf:RDF>
</metadata>

The about attribute takes an IRI as value; for a stand-alone SVG document, you could provide an empty value (= the base IRI of the document).

In this example I use the license property from Schema.org:

A license document that applies to this content, typically indicated by URL.

(The vocabulary Schema.org is supported by several big search engines.)

Matronna

Not sure if useful to you, but in SVG Tiny, you can use RDFa attributes on the SVG elements directly (i.e., not just as XHTML+RDFa inside of metadata). – Matronna

How would I extend this with a list of the work's author(s)? – Josephinajosephine

Having the same question as in the previous comment, I ended up looking how Inkscape stores author and license information in RDF tags (can be set in the document properties). – Caulicle