Re: edge attributes in JSON-LD

Hi Dan

In what way hasn't it worked out?

I used the schema:Role approach to reify schema:attendee relation in a genealogy project and it was, to my opinion, easy to apply and understandable.
Example: http://data.cubiss.nl/genealogy/Event596744427

John



Sent from my Samsung Galaxy smartphone.


-------- Original message --------
From: Dan Brickley <danbri@danbri.org>
Date: 31/03/2018 01:20 (GMT+01:00)
To: karlg <karl.geog@gmail.com>
Cc: Gregg Kellogg <gregg@greggkellogg.net>, Linked JSON <public-linked-json@w3.org>
Subject: Re: edge attributes in JSON-LD

At Schema.org we can't really claim Role has worked out well. I wouldn't advocate it for this.

It would be very interesting if a syntax could be found in JSON-LD 1.1, alongwith an optional named graphs view of the data. This would help close the gap wth Property Graphs too.

Dan

On Sat, 31 Mar 2018, 00:06 karlg, <karl.geog@gmail.com<mailto:karl.geog@gmail.com>> wrote:
Sub-classing schema.org<http://schema.org> Role, e.g. with SettingRole seems promising, thanks

kg

{
  "@context": "http://linkedpasts.org/lp-context.jsonld",
  "@type": "Place",
  "name": "Abingdon",
  �properties�: {�p1�: �___�, ...}
  "setting": [
    {
      "@type": "SettingRole",
      "setting": {
        "@type": "Place",
        "name": "Berkshire"
      },
      "startDate": "1600",
      "endYear": "1974"
    },
    {
      "@type": "SettingRole",
      "setting": {
        "@type": "Place",
        "name": "Oxfordshire"
      },
      "startDate": "1974",
      "endYear": "2018"
    }
  ]
}

On 3/30/18, 4:36 PM, "Gregg Kellogg" <gregg@greggkellogg.net<mailto:gregg@greggkellogg.net>> wrote:

On Mar 30, 2018, at 3:09 PM, Karl Grossner <karl.geog@gmail.com<mailto:karl.geog@gmail.com>> wrote:

Reopening this thread, as my current challenge relates closely:
I'm modeling historical Place attestations for gazetteer applications, and a potential linked.places JSON-LD modeling standard (a la linked.art). The idea is to build upon GeoJSON-LD.
Several attributes of Places are temporally indexed; i.e. may have a 'valid period', but are not amenable to event models in the same way as linked.art provenance is.

>From what I can tell, three options are @graph, n-ary relations, and rdf:Statement reification. I've rendered some sample records below. My question is whether there has emerged a best practice for this general problem of edge attributes. Any comments welcome at this stage. I have been having a conversation with @gklyne on this, here, which may (?) shed further light. https://github.com/LinkedPasts/lp-network/issues/1

While we could probably add something to perform reification on expansion, or transformation to RDF, it�s not clear how that would allow you to make statements about the statement, and it�s widely considered an archaic mechanism. And, it would substantially complicate the already complex API algorithms.

The issue of edge attributes in JSON-LD is really no different than for RDF in general. While there is no syntax for automatic reification of statements, they can of course be represented in JSON-LD.

The RDF 1.1 position is more likely that named graphs can be used for this purpose, although there are no built-in semantics. (Basically, put the statement in a named graph, and then make other meta-statements with the graph name as a subject). Your approach 01 is essentially this.

Schema.org<http://Schema.org> takes another approach using the Role class (and sub-classes) [1], and this can be used in JSON-LD to describe information about relationships. This is what I�ve used in some of my own projects.

Gregg

[1] http://schema.org/Role



thanks
--------
approach 01 (@graph; playground<https://tinyurl.com/y74p3pov> )
{
  "@context": "http://linkedpasts.org/assets/place-v4-context.jsonld",
  "related": [
    { "@id": "http://linkedpasts.org/graphs/01",
      "@graph": {"@id":"myplace:Abingdon","part_of":"myplace:Berkshire"},
      "when": {
        "timespans":
            {
                      "earliestYear": "1600",
                      "latestYear": "1974",
                      "label": "from 17c. to 1974"
                    }
      }
    },
    { "@id": "http://linkedpasts.org/graphs/02",
      "@graph": {"@id":"myplace:Abingdon", "part_of":"myplace:Oxfordshire"},
      "when": {
        "timespans":
            {
                      "earliestYear": "1974",
                      "latestYear": "2018",
                      "label": "from 1974"
                    }
      }
    },
    { "@id": "http://linkedpasts.org/graphs/03",
      "@graph": {"@id":"myplace:Oxford", "part_of":"myplace:Oxfordshire"},
      "when": {
          "timespans":
            {
                      "earliestYear": "1000",
                      "latestYear": "2018",
                      "label": "from 11c."
                    }
            }
    }
  ]
}

approach 02 (per property graph example given in this thread)
[
    {"@id": "", "@type": "rdf:BoundDataset"},
    {"@id": "p1", "name": "Abingdon", "type": "settlement", "_:parent_p1p3":"p3", "_:parent_p1p4":"p4"},
    {"@id": "p2", "name": "Oxford", "type": "settlement", "_:parent_p2p4": "p4"},
    {"@id": "p3", "name": "Berkshire", "type": "county"},
    {"@id": "p4", "name": "Oxfordshire", "type": "county"},
    {    "@id": "_:parent_p1p3",
        "rdfs:subPropertyOf": "hasParent",
        "earliestYear": 1600,
        "latestYear": 1974,
        "label": "from 17c. until 1974"},
    {    "@id": "_:parent_p1p4",
        "rdfs:subPropertyOf": "hasPparent",
        "earliestYear": 1974,
        "latestYear": 2018,
        "label": "from 1974"},
    {    "@id": "_:parent_p2p4",
        "rdfs:subPropertyOf": "hasParent",
        "earliestYear": 1000,
        "latestYear": 2018,
        "label": "from 11c."}
]

----
Karl Grossner
Technical Director,
World-Historical Gazetteer project for the
University of Pittsburgh World History Center
@kgeographer
Denver, CO