A couple of days ago I wrote:
> If you were to select a set of RDF ontologies intended to be used in the
> linked data of archival descriptions, then what ontologies would you
> select?
And in response Ben Companjen <[log in to unmask]> wrote the following post, which I think is absolutely wonderful. So wonderful in fact, that I am reposting it with only the tiniest bit of copy editing. I think it is worth a re-read. “Thank you, Ben!”
While I'm no archivist by training (information systems engineer I am),
I've learned a thing or two from having to work with EAD and its basis
for use, ISAD(G) (all citations below are from ISAD(G), 2nd edition). [1] As
with all information modelling, either inside or outside the Linked Data
domain, you should take a step back to look at the goal of the
description. When you have a list of what you want to describe, you can
start looking for ontologies.
You probably know this, but I was triggered by "Because many archival
descriptions are rooted in MARC records, and MODS is easily mapped from
MARC." to respond. IMO archival descriptions are rooted in rules for
description, not a specific file format.
So, when I [see] of (some of) the essences of archival description, I
think of:
* "The purpose of archival description is to identify and explain
the context and content of archival material in order to promote
its accessibility. This is achieved by creating accurate and
appropriate representations and by organizing them in accordance
with predetermined models." (§I.2)
* "… seven areas of descriptive information:
1. Identity Statement Area (where essential information is
conveyed to identify the unit of description)
2. Context Area (where information is conveyed about the origin
and custody of the unit of description)
3. Content and Structure Area (where information is conveyed
about the subject matter and arrangement of the unit of
description)
4. Condition of Access and Use Area (where information is
conveyed about the availability of the unit of description)
5. Allied Materials Area (where information is conveyed about
materials having an important relationship to the unit of
description)
6. Note Area (where specialized information and information that
cannot be accommodated in any of the other areas may be
conveyed).
7. Description Control Area (where information is conveyed on
how, when and by whom the archival description was prepared)."
(§I.11)
There is a distinction between the thing being described, and the
description itself, and both have an important role within the archival
description. (If anything so far causes confusion with anyone here, I
misunderstood and accept to be corrected :)) NB: this is one way of
thinking of descriptions. Incorporating the PROV-ontology would make
sense for expressing more/other aspects of the provenance of archival
entities, but I haven't got round to becoming an expert of PROV yet ;)
ISAD(G) lists 26 "elements that may be combined to constitute the
description of an archival entity".
Trying to translate these 'elements', I'd end up with possible a lot
more than 26 RDFS/OWL properties.
*Depending on the type of archival entity you can/should of course use
more specific ontologies.*
Let me list some properties and related ontologies.
* Identity statement area
o Identifiers - The URI, naturally, and other IDs. Could be
linked using dc(terms):identifier, or mods:identifier, or other
ontologies. Ideally there is some way of linking the domain of
the ID to the ID itself, because "box 101" is likely not unique
in the universe. Perhaps you want to publish a URI strategy
separately to explain how the URI was assembled/derived.
o Title - Again DC(terms), MODS, RDA
o Date(s) - You want properties that have a clear meaning. For
example, dcterms:created and mods:dateCreated assume it is clear
what "when the resource was created" means. DC terms are vague, I
mean general, on purpose. You could create some properties
`owl:subPropertyOf` dcterms date properties for this. I'd look
into EDTF for encoding uncertain dates and ranges and BCE dates
(MODS doesn't support BCE dates).
o Level of description - What kind of 'documentary unit' does the
description describe? A whole building's content or one piece of
paper? I don't know of any ontology with terms "fonds", …,
"file", "item", but you could say `<http URI> rdf:type <fonds
class URI>`.
o Extent and medium - Saying anything about extent and medium
should possible only happen on the lowest level of description.
Any higher level extent and medium should be calculated by
aggregating lower level descriptions. On the lowest level, refer
to class URIs. A combination of dimensions and material
{c|sh}ould be a class, e.g. A4 paper 80 grams/square meter.
* Context area
o Creator(s) and administrative/biographical history - As ISAD(G)
refers to ISAAR(CPF) for description of corporate bodies, people,
and families, this is a perfect example of using existing people-
and organisation-describing ontologies like FOAF, BIO, ORG, and
others are useful for separate descriptions of the people and
organisations involved. You want specific properties to describe
the roles of these 'agents' in the history of the archival
entity…
o Archival history and Immediate source of acquisition or
transfer - … and you would want them 'here' (of course there is
no particular order in which these properties are used). PREMIS
and PROV come to mind first for recording who did what to what,
(where and?) when and with what result. There are probably some
ontologies describing possible "events" as RDFS/OWL classes, so
you could link to those. The immediate source of acquisition or
transfer may be just another event.
* Content and structure area
o Scope and content - Descriptions, keywords, terms from
authority files about "scope (such as, time periods, geography)
and content, (such as documentary forms, subject matter,
administrative processes) … appropriate to the level of
description.": pretty natural fit for links to SKOS thesauri and
other ontologies of real-world 'things'. One might think of
dcterms:subject, dcterms:description, dcterms:temporalCoverage
etc., but describing *how* exactly such terms relate to the
archival entity needs more specific properties than "subject" et
al.
o Appraisal, destruction and scheduling information - Reasons for
including things and (possibly) removal of archival entities
should go very well in rules, and some types of rules go very
well in ontologies. Making this up as I type: <class of letters
written by the head of state> rdfs:subClassOf <class of 'things
to be kept'>. The actual selection and destruction actions could
be modelled in the same way as other actions are described for
provenance.
o Accruals - Whether more content can be expected probably
depends on other properties of the archival entity, like its
type(s) and creator(s). I don't know about specific properties to
record this, but <class of living heads of state archival
entities> rdfs:subClassOf <class of 'living' archival entities>?
There are ways of modelling rules for this, like the Rules
Interchange Format, but the rules may be defined by the archives
and archivists.
o System of arrangement - Thinking about this, I tend to think of
a collection of keywords to describe the arrangement of a
low-level archival entity like a folder or box: alphabetical, as
found on deceased's desk. But there is more, of course. Perhaps
using the Collection Ontology for low levels could help generate
higher level 'systems of arrangement'.
* Conditions of access and use area
o Conditions governing access and Conditions governing
reproduction - You can describe rights with the Creative Commons
Rights Expression Language.
o Language of material - mods:language maybe? Preferably used on
sub-document level and generated for higher-level descriptions.
o Physical characteristics / technical requirements - Conditions
should follow from their respective properties: <class of
PDF/A-1b files> ..:requiresForReading <class of PDF/A-1b readers>
and rules that say documents in <class A> are embargoed for 20
years after creation + a creation date can present enough
information to the agent to determine dcterms:dateAvailable.
o Finding aids - As a non-archivist I had some trouble
understanding the difference between descriptions and finding
aids and what the exact use of a finding aid was. Also, having
grown up with search engines, indexes, I think the concept may
eventually become extinct. I guess you could use foaf:page to
link a document-like finding aid to the archival entity and
rdfs:seeAlso to point to machine-actionable related things.
* Allied materials area
o Existence and location of originals/copies - PROV can be used
to link a copy to an original (and how the copy was created
etc.). `<X> prov:wasDerivedFrom <Y>. <Y> :isAt <AnotherArchive>.`
o Related units of description / Publication note - Use
properties that describe the specific relations among archival
entities. DC Terms has some useful ones, like for citations.
Related items can be derived from all or selected properties
automatically too.
* Notes area
o Notes - dcterms:description? Unlike a document containing rules
that needs to be finished at some time, Linked Data has no such
rule. You can always create a property with a well-defined
meaning to use for specific information.
* Description control area
o Archivist's note / dates of description - Who did what when,
where, why and how to the description itself. Same as for the
unit of description itself. This may be a good time to draw a bit
more attention to the question: *what is a description?* I don't
have a (/ there is no) final answer, but as The One True Written
Paper Description from long ago is becoming a set of triples, you
want to think about it. You could link versions of RDF documents
using PROV to record this information.
o Rules and conventions - A link to the rules and conventions for
description. Could also fit with the PROV provenance.
No, this is not a list of ontologies to use/explore right away, but I
hope you (and others) find it helpful, or perhaps even food for
discussion. Also, have a look at CIDOC-CRM. [2] It has lots of properties.
[1] ISAD(G) (http://bit.ly/1mmXMmJ) - "This standard provides general
guidance for the preparation of archival descriptions. It is to be used
in conjunction with existing national standards or as the basis for the
development of national standards."
[2] IDOC-CRM (http://www.cidoc-crm.org) - "The CIDOC Conceptual
Reference Model (CRM) provides definitions and a formal structure for
describing the implicit and explicit concepts and relationships used in
cultural heritage documentation.
--
Ben
—
Eric Morgan
