LinkML Project Posts

readme.md

LinkML Project Post

This was created following the LinkML tutorial

Schema

• projectpost.yaml contains the LinkML schema for a project post. There are separate classes for ProjectPost, File and FileLocation that utilize standard GeoSPARQL + WKT conventions.
• This schema sets the default prefix/context to regenschema, but uses a few DC terms for most of the semantic modelling.
• Project post files are referenced via the Regen IRI of the anchored data ?post dct:references regen:1111.rdf and the same Regen IRI is used as the subject for metadata about the file regen:111.rdf dct:title "File name"
  • This seems like the simplest approach for referencing files. There is no complexity of other blank or list nodes that the post uses to reference the files. Odering of files is not deterministic but could be solved with a separate order property.
  • More practically, I wonder if the order of files may be preserved simply by fact that the resolver (likely) returns the same JSON-LD document that was anchored. Would this work in the short term? If file order is important more semantic importance (eg when indexing/aggregating rdf data into a larger graph) then order could be added.
• Blank nodes are only generated in RDF serialization to properly model the location geo:hasGeometry with a geo:asWKT serialization.
• Relevant LinkML issue to allow distinguishing between a set and list: linkml/linkml#221

Data + validation

• data.json contains a simple JSON definition of a project post.
• To validate + convert to json-ld run: linkml-convert -s post.yaml data.json -t json-ld, This will yield the example in jsonld-data.jsonld
• JSON Schema + SHACL can be generated, attaching the SHACL here, but didn't investigate how this could be further constrained.

data.json

{
    "title": "Post title",
    "comment": "Post description",
    "files": [
        {
            "iri": "regen:1111.png",
            "name": "Image file name",
            "description": "Image description",
            "credit": "Paul",
            "location": {"wkt": "POINT(1 2)"}
        },
        {
            "iri": "regen:2222.pdf",
            "name": "File name",
            "description": "File description",
            "credit": "Paul"
        }
    ]
}

jsonld-data.jsonld

{
  "title": "Post title",
  "comment": "Post description",
  "files": [
    {
      "iri": "regen:1111.png",
      "name": "Image file name",
      "description": "Image description",
      "location": {
        "wkt": "POINT(1 2)"
      },
      "credit": "Paul"
    },
    {
      "iri": "regen:2222.pdf",
      "name": "File name",
      "description": "File description",
      "credit": "Paul"
    }
  ],
  "@type": "ProjectPost",
  "@context": {
    "dcterms": "http://purl.org/dc/terms/",
    "geo": "http://www.opengis.net/ont/geosparql#",
    "linkml": "https://w3id.org/linkml/",
    "regenschema": "https://schema.regen.network/",
    "@vocab": "https://schema.regen.network/",
    "credit": {
      "@id": "dcterms:creator"
    },
    "description": {
      "@id": "dcterms:description"
    },
    "iri": "@id",
    "location": {
      "@type": "@id",
      "@id": "geo:hasGeometry"
    },
    "name": {
      "@id": "dcterms:title"
    },
    "wkt": {
      "@id": "geo:asWKT"
    },
    "comment": {
      "@id": "dcterms:description"
    },
    "files": {
      "@type": "@id",
      "@id": "dcterms:references"
    },
    "title": {
      "@id": "dcterms:title"
    },
    "FileLocation": {
      "@id": "geo:Geometry"
    }
  }
}

project-shacl.ttl

# metamodel_version: 1.7.0
@prefix dcterms: <http://purl.org/dc/terms/> .
@prefix geo: <http://www.opengis.net/ont/geosparql#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix regenschema: <https://schema.regen.network/> .
@prefix sh: <http://www.w3.org/ns/shacl#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

regenschema:ProjectPost a sh:NodeShape ;
    sh:closed true ;
    sh:ignoredProperties ( rdf:type ) ;
    sh:property [ sh:class regenschema:File ;
            sh:nodeKind sh:IRI ;
            sh:order 2 ;
            sh:path dcterms:references ],
        [ sh:datatype xsd:string ;
            sh:maxCount 1 ;
            sh:minCount 1 ;
            sh:order 0 ;
            sh:path dcterms:title ],
        [ sh:datatype xsd:string ;
            sh:maxCount 1 ;
            sh:order 1 ;
            sh:path dcterms:description ] ;
    sh:targetClass regenschema:ProjectPost .

geo:Geometry a sh:NodeShape ;
    sh:closed true ;
    sh:ignoredProperties ( rdf:type ) ;
    sh:property [ sh:datatype xsd:string ;
            sh:maxCount 1 ;
            sh:order 0 ;
            sh:path geo:asWKT ] ;
    sh:targetClass geo:Geometry .

regenschema:File a sh:NodeShape ;
    sh:closed true ;
    sh:ignoredProperties ( rdf:type ) ;
    sh:property [ sh:datatype xsd:string ;
            sh:maxCount 1 ;
            sh:order 4 ;
            sh:path dcterms:creator ],
        [ sh:datatype xsd:string ;
            sh:maxCount 1 ;
            sh:order 2 ;
            sh:path dcterms:description ],
        [ sh:datatype xsd:string ;
            sh:maxCount 1 ;
            sh:order 0 ;
            sh:path regenschema:iri ],
        [ sh:datatype xsd:string ;
            sh:maxCount 1 ;
            sh:minCount 1 ;
            sh:order 1 ;
            sh:path dcterms:title ],
        [ sh:class geo:Geometry ;
            sh:maxCount 1 ;
            sh:nodeKind sh:BlankNode ;
            sh:order 3 ;
            sh:path geo:hasGeometry ] ;
    sh:targetClass regenschema:File .

projectpost.yaml

id: https://schema.regen.network/schemas/projectpost
name: projectpost
prefixes:
  linkml: https://w3id.org/linkml/
  dcterms: http://purl.org/dc/terms/
  geo: http://www.opengis.net/ont/geosparql#
  regenschema: https://schema.regen.network/
imports:
  - linkml:types
default_range: string
default_prefix: regenschema

classes:
  ProjectPost:
    attributes:
      title:
        required: true
        slot_uri: dcterms:title
      comment:
        slot_uri: dcterms:description
      files:
        range: File
        slot_uri: dcterms:references
        multivalued: true
        inlined_as_list: true
        list_elements_ordered: true
  File:
    attributes:
      iri:
        identifier: true
      name:
        required: true
        slot_uri: dcterms:title
      description:
        slot_uri: dcterms:description
      location:
        range: FileLocation
        slot_uri: geo:hasGeometry
      credit:
        slot_uri: dcterms:creator
  FileLocation:
    class_uri: geo:Geometry
    attributes:
      wkt:
        slot_uri: geo:asWKT