Querying and reasoning about Extended Dates and Times as Linked Data

Abstract

The Extended Date and Time Format (EDTF), first developed at the Library of Congress and now incorporated into the ISO 8601 standard for representing dates and times, specifies a standard syntax for recording uncertain or approximate Gregorian calendar dates, dates with missing parts, sets of possible dates, and open-ended or recurring intervals of time. Currently working with EDTF strings requires implementation of a custom parser and comparison logic. But if EDTF times, sets and intervals were modeled as Linked Data, standard tools for querying and reasoning could be applied to them. This poster will present a draft model of EDTF concepts based on the OWL Time Ontology, and will demonstrate how it could be used to query, compare, and reason about EDTF times, sets and intervals without the need for custom software.

Full text

Extended Dates and Times Time Ontology in OWL
The Extended Date and Time Format (EDTF) was developed at
the Library of Congress and is now incorporated into the ISO
8601 standard for representing dates and times. It specifies a
standard syntax for recording:
EDTF provides a compact, standardized syntax for complex
datetime expressions, but it require special EDTF-specific libraries
to do things like comparison and sorting with EDTF strings.
uncertain and/or approximate dates
?2021-07-~20
2021-07~
in July, around the 20th, maybe in 2021
around July 2021
dates with missing parts
202X
XXXX-07-XX
sometime in the 2020s
some day in July in some year
sets of dates
[2020,2021,2023..2025] one of the years 2020,
2021, 2023, 2024, or 2025
{2020,2021-07} the year 2020 and the
month July of 2021
intervals of time
2020/2021-07 starting sometime in 2020 and
ending sometime in July 2021
2021-07-20/ starting July 20, 2021 and
ending at an unknown time
ex:posterSessionStartDescription
a :DateTimeDescription ;
:unitType :unitMinute ;
:minute 15 ;
:hour 13 ;
:timeZone wikidata:Q2086913 ;
:day "---20"^^xsd:gDay ;
:dayOfWeek :Tuesday ;
:month "--07"^^xsd:gMonth ;
:year "2021"^^xsd:gYear .
The Time Ontology in OWL (OWL-Time) defines classes and
properties for describing the individual elements of dates and
times as separate resources, so that they can be queried and
reasoned about as triples, rather than strings.
However, OWL-Time alone cannot express all of the date
constructs covered by EDTF.
https://aeshin.org/
ryanshaw@unc.edu
Ryan Shaw
https://periodo.github.io/edtf-ontology/
The EDTF Ontology provides concepts for expressing EDTF
constructs using OWL-Time. The goal is to support translation of
EDTF strings into structured descriptions that can be queried and
reasoned about using standard RDF/OWL tools.
Bridging the Gap
While the draft ontology covers the entirety of EDTF, there is still
work to be done:
‣ rules for automatically converting EDTF strings to triples
‣ mapping to other temporal ontologies such as CIDOC-CRM
‣ perhaps supporting SHACL or ShEx as an alternative to OWL
If you're interested, please get involved:
https://github.com/periodo/edtf-ontology/discussions