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Digital Object (byte stream) properties

About

A review of potential approaches to describing the properties for a type of digital object. Here a DO is a simple byte stream. It could be a zip, jpeg, PDF or CSV. A DO might also be a formal package description like a Frictionless Data Package package.json manifest document that itself is made up of a set of DOs by reference.

Different kernels

There are a few different sources we are looking at that could provide guidance on how to describe the small metadatsa kernel for a DO. Note this is just a small set of elements for an object and not intended to describe a single instance or collection of objects that might form a dataset and be more easily described by schema:DataSet or DCAT:DataSet.

So while a single DO might be used to define a data set as defined by schema.org/DataSet or DCAT, we want that to be a new object distinct from the byte stream DO. If that is acceptable, then we need to define a small bit of core metadata to associate with a DO. It's also felt that the presence of spatial, temporal, measurement or other metadata would be scoped into the dataset that a DO is a member of (represented by a new object) and not the DO itself. The DO is simply the byte stream.

References reviewed:

  • Frictionless Data Packages (resource node) https://frictionlessdata.io/specs/data-resource/ Here we are looking only at data-resource as an object that would itself or with other objects be referenced by a full package.
  • PID Kernel WG RDA https://www.rd-alliance.org/groups/pid-kernel-information-wg Though focused on PIDs there seems some value in considering this kernel and its potential use with digital objects.
  • DID or Decentralized Identifiers https://w3c-ccg.github.io/did-spec/ is about self sovereign digital identifiers. So again more focused on PIDs but now in a decentralized manner. Still, again this seems to have enough connection to digital objects to merit review.
  • Schema.org type DigitalDocument https://schema.org/DigitalDocument is looking for something than be associated with a digital object as opposed to a data set or catalog.
  • DCAT-2 https://w3c.github.io/dxwg/dcat/ This section needs attention. Can we leverage DCAT to describe a DO/byte stream as opposed to a data set or catalog as differentiated in the above text.

Note: No attempt has been made to order these across the rows... that needs to be done

FDP (resource) PID DID schema.org DCAT-2
name pid id schema:DigitalDocument
path KernelInformationProfile publicKey schema:name
title digitalObjectType authentication schema:URL
description digitalObjectLocation services schema:about
format digitalObjectPolicy service:id schema:description
mediatype etag services:type schema:encodingFormat
encoding dateModified services:serviceEndpoint schema:fileSize
bytes dateCreated schema:identifier
(via PropVal, see below)
hash version schema:isBasedOn
schema wasDerivedFrom schema:license
sources specialixationOF schema:dateModified
license wasRevisionOF schema:dateCreated
hasPrimarySource xyz:Type (domain typing)
wasQuotedFrom
alternatOF

This is an example of the current schema:DigitalDocument package we are generating

{
  "@graph": [
    {
      "@id": "_:bbj6s49vtr9b9lop9n40g",
      "@type": "http://schema.org/PropertyValue",
      "http://schema.org/propertyID": "SHA256",
      "http://schema.org/value": "e88c1fa53004f75e2f1a761284c42e22d69e1750e70904c02c0b726ff42250ad"
    },
    {
      "@id": "http://opencoredata.org/id/do/bj6s49vtr9b9lop9n40g",
      "@type": "http://www.schema.org/DigitalDocument",
      "http://schema.org/additionType": {
        "@id": "http://opencoredata.org/voc/csdco/v1/ICDFiles"
      },
      "http://schema.org/dateCreated": "2009-11-02",
      "http://schema.org/description": "Digital object of type ICD named YNP3-ABD09-1A-1L-1.pdf for CSDCO project YNP3",
      "http://schema.org/encodingFormat": "application/pdf",
      "http://schema.org/identifier": {
        "@id": "_:bbj6s49vtr9b9lop9n40g"
      },
      "http://schema.org/isRelatedTo": "YNP3",
      "http://schema.org/license": {
        "@id": "http://example.com/cc0.html"
      },
      "http://schema.org/name": "YNP3-ABD09-1A-1L-1.pdf",
      "http://schema.org/url": {
        "@id": "http://opencoredata.org/id/do/e88c1fa53004f75e2f1a761284c42e22d69e1750e70904c02c0b726ff42250ad"
      }
    }
  ],
  "@id": "http://opencoredata.org/objectgraph/id/e88c1fa53004f75e2f1a761284c42e22d69e1750e70904c02c0b726ff42250ad"
}

https://schema.org/identifier example pattern example

{
 "@context": "http://schema.org/",
 "@type": "LocalBusiness",
 "name": "A UK Organization Ltd",
 "address": "1 A Street, London"
 "identifier": {
 "@type": "PropertyValue",
   "propertyID": "Company Number",
   "value":  "99065782"
   },
}