W3C home > Mailing lists > Public > public-linked-json@w3.org > July 2013

Re: Defining property labels in external context document

From: Adrian Pohl <pohl@hbz-nrw.de>
Date: Thu, 18 Jul 2013 13:40:41 +0200
Message-Id: <51E7F0590200001400051272@agrippa.hbz-nrw.de>
To: "Alexey Zakhlestin" <indeyets@gmail.com>
Cc: <public-linked-json@w3.org>
>>> On 18.7.2013 at 12:14, Alexey Zakhlestin <indeyets@gmail.com> wrote: 

> It looks like you're trying to mix different levels.
> Labels are usually defined on RDF-Schema level, where you define classes, 
> properties, their relationships and their metadata (including human-readable 
> labels).

Markus said something similar. But there are at least two problems with defining labels on RDF-Schema level:

1. Often, German labels (which I also need) for a property don't exist. If you offer to add these to the vocabulary you might not even get an answer (I offered my help for label translation to DC once and never got an answer) or it might take a lot of time until you have these labels.
2. Even if a property label exists on RDF-Schema level, this might not be the one you would like to use, e.g. for the purpose of presentation. And sometimes it may well be necessary to define different labels for a property in different contexts. E. g. the property label for a cataloger might be more technical than the one I provide to an end user for the same property. I can use Fresnel [1] (which we have done until now) or something else for specifying defining custom property labels but would be quite happy if this could be done in a JSON-LD context document.

> @context is an instruction to processor, which tells that "name" is actually 
> a http://schema.org/name but it doesn't tell what it means.
> Meaning is encoded in RDF-schema

Hmm. This argument doesn't convince me as I think you can already do "meaningful" things in a JSON-LD context doc that are usually done on vocabulary level. See the Example 21 of the spec:

{
  "@context":
  {
    "modified":
    {
      "@id": "http://purl.org/dc/terms/modified",
      "@type": "http://www.w3.org/2001/XMLSchema#dateTime"
    }
  },
...
}

Typing a literal also tells what something means and it can be done in a JSON-LD context document. With the reasoning that meaning is provided on the RDF-Schema level one could also say that @type definition in @context isn't valid and should rather be done in the vocabulary. One could easily look up the property referenced in a @context and then take the value that is defined as rdfs:range.

- Adrian

[1] http://www.w3.org/2005/04/fresnel-info/

> JSON-LD @context is not an alternative to this. It just helps to convert 
> shorter json-document into valid RDF.
> 
> @context is an instruction to processor, which tells that "name" is actually 
> a http://schema.org/name but it doesn't tell what it means.
> Meaning is encoded in RDF-schema

>>> On 18.7.2013 at 12:14, Alexey Zakhlestin <indeyets@gmail.com> wrote: 

> On 18.07.2013, at 14:00, "Adrian Pohl" <pohl@hbz-nrw.de> wrote:
> 
>> Besides listing the different properties and defining their short names and 
> values, I also thought it would make sense to define the English and German 
> property labels. This would be quite useful as different uses of one context 
> document would present the same labels to end users.
> 
> It looks like you're trying to mix different levels.
> Labels are usually defined on RDF-Schema level, where you define classes, 
> properties, their relationships and their metadata (including human-readable 
> labels).
> 
> JSON-LD @context is not an alternative to this. It just helps to convert 
> shorter json-document into valid RDF.
> 
> @context is an instruction to processor, which tells that "name" is actually 
> a http://schema.org/name but it doesn't tell what it means.
> Meaning is encoded in RDF-schema
Received on Thursday, 18 July 2013 11:41:28 UTC

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