PLATO — Place Attestation Ontology
language en

PLATO — Place Attestation Ontology

Release: 2026-02-16

Revision:
0.1.0-draft
Authors:
Stephen Gadd✉
Contributors:
Pelagios Network Place Working Group
See also:
https://pelagios.org/place-attestation-ontology/index-en.html
Download serialization:
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License:
https://creativecommons.org/licenses/by/4.0/
Visualization:
Visualize with WebVowl
Cite as:
Stephen Gadd. PLATO — Place Attestation Ontology. Revision: 0.1.0-draft.
Provenance of this page
Ontology Specification Draft

PLATO — Place Attestation Ontology: Overview back to ToC

This ontology has the following classes and properties.

Classes

Object Properties

Data Properties

PLATO — Place Attestation Ontology: Description back to ToC

An ontology for representing historical place knowledge as attestations: bundles of evidence linking Things (places, routes, networks, and other entities related to place) to Names, Geometries, Timespans, Types, and Authorities with full provenance. Developed by the Pelagios Network's Place Working Group, led by the Institute for Spatial History Innovation (ISHI), University of Pittsburgh. PLATO formalises the WHG v4 data model, in which the Attestation is the fundamental unit of contributed knowledge. It unifies and supersedes the Linked Places Format (LPF) and Linked Traces.

Cross-reference for PLATO — Place Attestation Ontology classes, object properties and data properties back to ToC

This section provides details for each class and property defined by PLATO — Place Attestation Ontology.

Classes

Attestationc back to ToC or Class ToC

IRI: https://w3id.org/plato#Attestation

A bundle of evidence asserting that a particular Thing had a particular Name, Geometry, Type, or combination thereof, during a particular Timespan, according to a particular Authority. The Attestation node carries only metadata; its semantic content is defined entirely by its outgoing relationships. IMPORTANT: Attestations are document nodes in the graph, not edges. They are instances of plato:Attestation (a class), not instances of owl:ObjectProperty. This design enables meta-attestations and full provenance tracking.
has super-classes
Entity c
is in domain of
attests about op, attests geometry op, attests name op, attests timespan op, attests type op, certainty dp, certainty note dp, connection metadata dp, contributed by op, created dp, has relation type op, meta-attestation about op, meta-attestation type op, modified dp, notes dp, relates to op, sequence dp, sourced by op
is in range of
contains attestation op, meta-attestation about op

Authorityc back to ToC or Class ToC

IRI: https://w3id.org/plato#Authority

Abstract superclass for all reference entities that provide provenance or semantic grounding for attestations. Subtypes include Source, Dataset, Period, RelationType, and CertaintyLevel.
has sub-classes
Certainty Level c, Dataset c, Period c, Relation Type c, Source c
is in domain of
authority URI dp, title dp, version dp
is in range of
identity sourced by op, sourced by op

Candidatec back to ToC or Class ToC

IRI: https://w3id.org/plato#Candidate

An algorithm-generated match candidate between two Things, produced by the PLACE clustering engine. Candidates carry a similarity score, algorithm version, and review status. They are explicitly not IdentityRelations — they become IdentityRelations only when confirmed by a human reviewer (linked back via plato:promoted_from).
is in domain of
algorithm version dp, candidate thing op, generated at dp, similarity score dp, source thing op, status dp
is in range of
promoted from op

Certainty Levelc back to ToC or Class ToC

IRI: https://w3id.org/plato#CertaintyLevel

A defined level of certainty for use in attestations, allowing projects to standardise their confidence vocabulary.
has super-classes
Authority c

Contributorc back to ToC or Class ToC

IRI: https://w3id.org/plato#Contributor

A person, team, or automated process that creates attestations. Aligned with both foaf:Agent and prov:Agent for provenance chain-of-custody tracking. Contributors should be identified using persistent identifiers where possible. For persons, ORCID (https://orcid.org/) is strongly recommended and may be required by specific implementations. ORCID identifiers should use the full URI format (https://orcid.org/0000-0000-0000-0000) rather than just the numeric portion, as ORCID is particular about proper URI formatting for linked data interoperability. For organizations, ROR (https://ror.org/) or ISNI identifiers are recommended. Proper identification ensures accurate attribution, enables citation, and supports research assessment.
has super-classes
Agent c, Agent c
is in domain of
ORCID dp, affiliation op, affiliation (string) dp, contributor URL dp, contributor identifier dp, contributor name dp, contributor role dp, email dp
is in range of
asserted by op, contributed by op, owner op

Datasetc back to ToC or Class ToC

IRI: https://w3id.org/plato#Dataset

A collection-level authority: a published gazetteer, a contributed dataset, or an external authority corpus (GeoNames, Wikidata, TGN, OSM, Pleiades). Carries metadata such as title, version, publisher, licence, and URI.
has super-classes
Authority c
is in domain of
licence dp, publisher dp
is in range of
part of op

Gazetteerc back to ToC or Class ToC

IRI: https://w3id.org/plato#Gazetteer

A mutable, versioned workspace of Things and their associated Attestations, owned by a contributor or team. Replaces the WHG v3 concepts of Dataset, Dataset Collection, and Place Collection. A Gazetteer can be incrementally edited, enriched, and corrected without re-ingestion.
has super-classes
Dataset c
is in domain of
contains attestation op, contains thing op, member of group op, owner op, status dp

Gazetteer Groupc back to ToC or Class ToC

IRI: https://w3id.org/plato#GazetteerGroup

A thematic or organisational grouping of Gazetteers (e.g. 'EMEW — Gazetteer of Early Modern England and Wales').
is in range of
member of group op

Geometryc back to ToC or Class ToC

IRI: https://w3id.org/plato#Geometry

A spatial representation of a Thing's extent or location. Geometries are independent, reusable entities. The same Geometry may be referenced by multiple Attestations across different Things or time periods. Note: GeometryCollection is not supported in some graph database implementations. For heterogeneous geometry sets (e.g., both point and polygon), use multiple Geometry entities linked through separate attestations.
has super-classes
Geometry c
is in domain of
bounding box dp, convex hull op, geometry GeoJSON dp, geometry WKT op, precision in kilometers dp, relative qualifier op, relative to op, representative point op, source CRS dp, spatial precision dp
is in range of
attests geometry op

Identity Relationc back to ToC or Class ToC

IRI: https://w3id.org/plato#IdentityRelation

An assertion that two Things refer to the same real-world entity. Carries its own provenance (who asserted it, on what basis), certainty (how confident the assertion is), and identity semantics (exactMatch, closeMatch, related). Identity relations are distinct from scholarly Thing-to-Thing relations, which describe substantive historical relationships between different entities. They are also distinct from Candidates, which are algorithm-generated candidates not yet confirmed by human review.
is in domain of
asserted at dp, asserted by op, identity basis dp, identity certainty dp, identity object op, identity sourced by op, identity subject op, identity type dp, promoted from op

Namec back to ToC or Class ToC

IRI: https://w3id.org/plato#Name

A toponym or appellation for a Thing. Names are independent, reusable entities. The association between a Name and a Thing is always mediated by an Attestation, which provides temporal scope and provenance.
is in domain of
IPA dp, language dp, name embedding dp, name type dp, relative qualifier op, relative to op, romanized dp, script dp, toponym dp, transliteration system dp
is in range of
attests name op, relative to op

Organizationc back to ToC or Class ToC

IRI: https://w3id.org/plato#Organization

An organization to which a Contributor is affiliated. This is a lightweight class defined primarily to avoid ambiguity in ontology visualizations. Organizations can be further described using properties from FOAF, schema.org, or other ontologies. Organizations should use persistent identifiers where possible: - ROR (Research Organization Registry): https://ror.org/ - ISNI (International Standard Name Identifier) - Wikidata QIDs
is in range of
affiliation op

Periodc back to ToC or Class ToC

IRI: https://w3id.org/plato#Period

A named historical period (e.g. 'Byzantine', 'Early Modern'), optionally linked to PeriodO or defined locally. Includes temporal bounds for period-based querying.
has super-classes
Authority c
is in domain of
PeriodO URI dp, has timespan op, period label dp, spatial coverage dp
is in range of
relative to op

Relation Typec back to ToC or Class ToC

IRI: https://w3id.org/plato#RelationType

A vocabulary entry defining a semantic relationship between Things: 'capital_of', 'successor_to', 'connected_by_trade_route_to', etc. Carries a label, an inverse label, and domain/range constraints. This allows the vocabulary of historical relationships to grow without modifying the core ontology.
has super-classes
Authority c
is in domain of
domain constraint dp, inverse label dp, range constraint dp, relation label dp
is in range of
has relation type op

Sourcec back to ToC or Class ToC

IRI: https://w3id.org/plato#Source

A citable source of evidence: a manuscript, chronicle, tax record, map, scholarly article, or other document. Sources are the primary provenance anchor for attestations. A Source may reference its parent Dataset via plato:partOf.
has super-classes
Authority c
is in domain of
bibliographic string dp, part of op

Thingc back to ToC or Class ToC

IRI: https://w3id.org/plato#Thing

A stable, persistent identity representing a place or other historical entity related to place (routes, networks, administrative units, etc.). Things are not defined by any single attestation; they are the point of convergence for multiple attestations from different sources, periods, and contributors.
has super-classes
Entity c
is in domain of
country codes dp, identifier dp, namespace dp
is in range of
attests about op, candidate thing op, contains thing op, identity object op, identity subject op, relates to op, relative to op, source thing op

Timespanc back to ToC or Class ToC

IRI: https://w3id.org/plato#Timespan

A temporal interval with start and end bounds. Timespans are independent, reusable entities that may be shared across multiple Attestations. Precision and uncertainty are expressed through the start and end bound properties. Aligned with W3C Time Ontology and compatible with PeriodO period definitions.
has super-classes
Proper Interval c
is in domain of
EDTF string dp, PeriodO URI dp, end earliest dp, end latest dp, end precision dp, open end dp, open start dp, precision value dp, relative qualifier op, relative to op, start earliest dp, start latest dp, start precision dp, timespan label dp
is in range of
attests timespan op, has timespan op, relative to op

Typec back to ToC or Class ToC

IRI: https://w3id.org/plato#Type

A classification or category for a Thing, typically drawn from a controlled vocabulary such as the Getty Art & Architecture Thesaurus (AAT). Types are independent, reusable entities.
has super-classes
Concept c
is in domain of
relative qualifier op, relative to op, source label dp, type identifier dp, type label dp
is in range of
attests type op, relative to op

Object Properties

affiliationop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#contributor_affiliation

Organizational affiliation of the contributor. Links to a plato:Organization entity, which can be further described using FOAF, schema.org, or other ontology properties. Organizations should ideally use persistent identifiers (ROR, ISNI, etc.). For simple cases, use contributor_affiliation_string for free-text affiliation names.
has domain
Contributor c
has range
Organization c

asserted byop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#identity_asserted_by

The agent who made or confirmed this identity assertion.
has domain
Identity Relation c
has range
Contributor c

attests aboutop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#attests_about

Links an Attestation to the Thing it is about. Every attestation must have exactly one subject Thing. This is the primary entity being described by the bundled name, geometry, timespan, and type assertions. Functional property: each attestation has exactly one subject Thing.

has characteristics: functional

has domain
Attestation c
has range
Thing c

attests geometryop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#attests_geometry

Links an Attestation to a Geometry it asserts for the Thing. An attestation may assert multiple geometries (e.g., point and polygon) or no geometry at all (e.g., name-only attestations from textual sources).
has domain
Attestation c
has range
Geometry c

attests nameop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#attests_name

Links an Attestation to a Name it asserts for the Thing. An attestation may assert multiple names (e.g., primary name and variants) or no name at all (e.g., geometry-only attestations).
has domain
Attestation c
has range
Name c

attests timespanop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#attests_timespan

Links an Attestation to the Timespan during which the attested properties (name, geometry, type) were applicable. Distinct from the attestation's creation date: this is the historical timespan being asserted, not when the assertion was made.
has domain
Attestation c
has range
Timespan c

attests typeop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#attests_type

Links an Attestation to a Type classification it assigns to the Thing. An attestation may assert multiple types or no type at all.
has domain
Attestation c
has range
Type c

candidate thingop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#candidate_candidate

has domain
Candidate c
has range
Thing c

contains attestationop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#contains_attestation

Links a Gazetteer to an Attestation contributed within it.
has domain
Gazetteer c
has range
Attestation c

contains thingop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#contains_thing

Links a Gazetteer to a Thing it contains.
has domain
Gazetteer c
has range
Thing c

contributed byop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#contributed_by

The agent (person, team, or process) who created this attestation. Semantically equivalent to PROV-O's prov:wasAttributedTo for provenance tracking. We don't use formal rdfs:subPropertyOf to avoid importing PROV-O's domain/range constraints. Distinct from sourced_by, which indicates the historical source being cited.
has domain
Attestation c
has range
Contributor c

convex hullop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#hull

has domain
Geometry c
has range
wkt Literal c
is also defined as
data property

geometry WKTop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#geo_wkt

has domain
Geometry c
has range
wkt Literal c
is also defined as
data property

has relation typeop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#has_relation_type

Specifies the semantic type of a Thing-to-Thing relationship attested by an Attestation. References a RelationType authority which defines the relationship's label, inverse, and domain/range constraints. Examples: 'capital_of', 'successor_to', 'connected_by_trade_route_to'. The extensible vocabulary pattern allows new relationship types to be added as Authority records without modifying the ontology.
has domain
Attestation c
has range
Relation Type c

has timespanop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#has_timespan

Links a Period authority to its temporal extent, represented as a Timespan node. Used for locally-defined periods or when more detailed temporal modeling is needed than provided by external period definitions.
has domain
Period c
has range
Timespan c

identity objectop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#identity_object

The second Thing in an identity assertion.
has domain
Identity Relation c
has range
Thing c

identity sourced byop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#identity_sourced_by

The Authority (Source or Dataset) that provides evidence for this identity assertion, if any.
has domain
Identity Relation c
has range
Authority c

identity subjectop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#identity_subject

The first Thing in an identity assertion.
has domain
Identity Relation c
has range
Thing c

member of groupop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#member_of_group

Links a Gazetteer to a GazetteerGroup.
has domain
Gazetteer c
has range
Gazetteer Group c

meta-attestation aboutop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#meta_attestation_about

Links a meta-Attestation to the Attestation it comments on or relates to. Used with plato:has_meta_type to specify the nature of the relationship. Example: A meta-attestation might assert that one source's geometry attestation contradicts another source's geometry attestation for the same Thing.
has domain
Attestation c
has range
Attestation c

meta-attestation typeop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#has_meta_type

The nature of a meta-attestation's relationship to its target attestation. Should reference a controlled vocabulary concept defining the relationship type. Standard values include: - 'contradicts': asserts the target attestation is incorrect - 'supports': provides additional evidence for the target attestation - 'supersedes': replaces the target attestation with newer information - 'refines': provides more precise information than the target - 'challenges': questions the target attestation's validity - 'bundles': groups the target with other related attestations Using SKOS concepts rather than strings enables vocabulary management and multilingual labels.
has domain
Attestation c
has range
Concept c

ownerop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#gazetteer_owner

has domain
Gazetteer c
has range
Contributor c

part ofop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#partOf

Links a Source to its parent Dataset.
has domain
Source c
has range
Dataset c

relates toop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#relates_to

Links an Attestation to a second Thing, asserting a relationship between the Attestation's subject Thing (via attests_about) and this target Thing. The semantic nature of the relationship is specified by plato:has_relation_type, which references a RelationType authority. Example: An attestation about Constantinople that relates_to the Byzantine Empire with relation_type "capital_of" asserts that "Constantinople was the capital of the Byzantine Empire".
has domain
Attestation c
has range
Thing c

relative qualifierop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#relative_qualifier

A controlled-vocabulary term describing the relative relationship when bearing and distance are not applicable or not sufficient. Should point to a concept in a SKOS concept scheme (e.g. plato:Near, plato:Within, plato:Beyond, plato:UpstreamOf, plato:BetweenXAndY, plato:DuringReignOf, plato:VariantOf). Using URIs rather than free text enables machine reconciliation across gazetteers that describe relativity differently.
has domain
Geometry c or Name c or Timespan c or Type c
has range
Concept c

relative toop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#relative_to

Links a facet node to its anchor entity, indicating that this facet is defined relationally rather than absolutely. The anchor is typically a Thing, Period, or another facet (Name, Timespan, etc.). Common patterns: - Spatial relativity: "20km east of Nanjing" (anchor is a Thing) - Temporal relativity: "during the reign of Justinian" (anchor is a Period) - Name relativity: "also known as Rome" (anchor is another Name)
has domain
Geometry c or Name c or Timespan c or Type c
has range
Name c or Period c or Thing c or Timespan c or Type c

representative pointop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#repr_point

has domain
Geometry c
has range
wkt Literal c
is also defined as
data property

source thingop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#candidate_source

has domain
Candidate c
has range
Thing c

sourced byop back to ToC or Object Property ToC

IRI: https://w3id.org/plato#sourced_by

Links an Attestation to the Authority (typically a Source or Dataset) that grounds it. This provides the provenance chain for the attestation. Semantically equivalent to PROV-O's prov:wasDerivedFrom, indicating the authority is the origin of the attested knowledge. We don't use formal rdfs:subPropertyOf to avoid importing PROV-O's domain/range constraints which conflict with PLATO's class structure.
has domain
Attestation c
has range
Authority c

Data Properties

affiliation (string)dp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#contributor_affiliation_string

Free-text organizational affiliation when a structured Organization entity is not available. Example: "University of Pittsburgh, Institute for Spatial History Innovation"
has domain
Contributor c
has range
string

algorithm versiondp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#algorithm_version

has domain
Candidate c
has range
string

asserted atdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#identity_asserted_at

has domain
Identity Relation c
has range
date Time

authority URIdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#authority_uri

has domain
Authority c
has range
any U R I

bearingdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#relative_bearing

Compass bearing from the anchor, in degrees (0–360). Primarily used for relative geometries: '90' means east of the anchor. May carry its own uncertainty or fuzziness.
has range
float

bibliographic stringdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#bibliographic_string

A formatted citation string for this source.
has domain
Source c
has range
string

bounding boxdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#bbox

Bounding box as array: [min_lon, min_lat, max_lon, max_lat]. Enables fast spatial filtering. Format: comma-separated string or JSON array depending on serialization context.
has domain
Geometry c
has range
string

certaintydp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#certainty

Overall certainty of this attestation, from 0.0 (completely uncertain) to 1.0 (completely certain). This represents the contributor's confidence in the bundle as a whole. Individual facets (Name, Geometry, Timespan) can have their own uncertainty values that may differ from the attestation's overall certainty.
has domain
Attestation c
has range
float

certainty notedp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#certainty_note

Free-text explanation of the certainty assessment. Should describe the basis for the certainty value: quality of evidence, degree of scholarly consensus, reliability of source, etc.
has domain
Attestation c
has range
string

connection metadatadp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#connection_metadata

Structured metadata for network-type attestations. Can encode information about trade goods, flow direction, capacity, frequency, or other properties of network connections. Format is implementation- specific (JSON recommended) but should be documented in the gazetteer's metadata.
has domain
Attestation c
has range
string

contributor identifierdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#contributor_identifier

Additional persistent identifier for the contributor. Can be used for identifiers other than ORCID, such as: - ISNI (International Standard Name Identifier) - VIAF (Virtual International Authority File) - Wikidata QID (for persons or organizations) - Internal system identifiers When using this property, specify the identifier type in the value (e.g., "ISNI:0000000121032683" or "VIAF:12345678").
has domain
Contributor c
has range
string

contributor namedp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#contributor_name

The name of the contributor (person, team, or automated process). For persons, should be the full name as preferred by the contributor. For teams, the team name. For automated processes, a descriptive name.
has domain
Contributor c
has range
string

contributor roledp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#contributor_role

Role of the contributor in the project or gazetteer. Examples: 'principal_investigator', 'data_curator', 'student_researcher', 'automated_process', 'external_contributor'. Helps understand the context and authority of contributions.
has domain
Contributor c
has range
string

contributor URLdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#contributor_url

Website or profile URL for the contributor (personal website, institutional page, project page, GitHub profile, etc.). Provides additional context about the contributor's work and identity.
has domain
Contributor c
has range
any U R I

country codesdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#ccodes

ISO 3166-1 alpha-2 country codes associated with this Thing.
has domain
Thing c
has range
string

createddp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#created

Timestamp when this attestation was created. This is the contribution date, not the historical timespan being attested (use attests_timespan for that). Semantically equivalent to PROV-O's prov:generatedAtTime. We don't use formal rdfs:subPropertyOf to avoid importing PROV-O constraints.
has domain
Attestation c
has range
date Time

distancedp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#relative_distance

Distance from the anchor, in metres. Primarily used for relative geometries. May carry its own uncertainty or fuzziness.
has range
float

domain constraintdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#relation_domain

Valid subject type for this relation.
has domain
Relation Type c
has range
string

EDTF stringdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#edtf_string

Extended Date/Time Format (EDTF) representation of this timespan. Provides standardized string encoding for interchange with systems using EDTF. Optional but recommended for interoperability with library and archival systems. Example: '1453-05-29/1453-05-29' or '1450~/1453~' for approximate dates.
has domain
Timespan c
has range
string

emaildp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#contributor_email

Contact email address for the contributor. Useful for collaboration and correspondence about contributed data.
has domain
Contributor c
has range
string

end earliestdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#end_earliest

The earliest possible end date for this timespan. Together with end_latest, defines the uncertainty range for when the interval ended. May be null for unknown or deliberately open-end intervals.
has domain
Timespan c
has range
string

end latestdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#end_latest

The latest possible end date for this timespan. For certain dates, this equals end_earliest. For uncertain dates, defines the end of the uncertainty range for when the interval ended.
has domain
Timespan c
has range
string

end precisiondp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#end_precision

Temporal granularity of the end bound. Values: 'year', 'decade', 'century', 'era', 'geological_period'.
has domain
Timespan c
has range
string

fuzzinessdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#fuzziness

Ontological fuzziness: a measure of how inherently vague or indeterminate the facet's referent is, from 0.0 (crisp, sharply bounded) to 1.0 (maximally vague). Distinct from uncertainty: fuzziness is a property of the thing itself, not of our knowledge of it. A regional boundary that was never precisely defined has high fuzziness regardless of how much evidence we have.
has range
float

fuzziness notedp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#fuzziness_note

Free-text explanation of the nature of ontological fuzziness (e.g. 'regional boundary was never formally demarcated', 'name used inconsistently across contemporary sources', 'transition was gradual rather than a discrete event').
has range
string

generated atdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#generated_at

has domain
Candidate c
has range
date Time

geometry GeoJSONdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#geo_json

GeoJSON representation of the geometry. Used for web mapping applications and LPF export. Should be a valid GeoJSON geometry object (not a Feature or FeatureCollection).
has domain
Geometry c
has range
string

geometry WKTop back to ToC or Data Property ToC

IRI: https://w3id.org/plato#geo_wkt

has super-properties
as W K T dp
is also defined as
object property

identifierdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#thing_identifier

The stable, persistent identifier for this Thing.
has domain
Thing c
has range
string

identity basisdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#identity_basis

Free-text explanation of the evidence or reasoning supporting this identity assertion (e.g. 'coordinates within 500m and name forms are cognate', 'identified by contributor during reconciliation review', 'confirmed via TGN cross-reference').
has domain
Identity Relation c
has range
string

identity certaintydp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#identity_certainty

Confidence in the identity assertion, from 0.0 to 1.0. This is the epistemic certainty of the asserter, distinct from identity_type which describes the semantic nature of the relationship. A closeMatch can have high certainty ('I'm confident these are close but not exact') and an exactMatch can have low certainty ('I think they're identical but I'm not sure').
has domain
Identity Relation c
has range
float

identity typedp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#identity_type

The semantic strength of the identity assertion: 'exactMatch' — the two Things are unambiguously the same entity. 'closeMatch' — the two Things are believed to be the same entity but with some residual ambiguity (e.g. differing granularity, overlapping but not identical scope). 'related' — the two Things are closely associated but may not be strictly identical (e.g. a settlement and its administrative district, or successive phases of a site that might or might not constitute continuity).
has domain
Identity Relation c
has range
string

inverse labeldp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#inverse_label

Inverse label (e.g. 'has_capital').
has domain
Relation Type c
has range
string

IPAdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#ipa

International Phonetic Alphabet representation of the name's pronunciation. Enables phonetic search and comparison across scripts and languages.
has domain
Name c
has range
string

languagedp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#language

BCP 47 language tag for this name (e.g., 'ar' for Arabic, 'zh-Hans' for Simplified Chinese). Recommended: use ISO 639-3 three-letter codes within BCP 47 for better granularity (e.g., 'ara', 'cmn').
has domain
Name c
has range
string

licencedp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#licence

has domain
Dataset c
has range
any U R I

modifieddp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#modified

Timestamp when this attestation was last modified. Enables tracking of editorial changes and versioning.
has domain
Attestation c
has range
date Time

name embeddingdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#name_embedding

Vector embedding for phonetic similarity search. Typically a 256-dimensional vector generated from the name's phonetic form, enabling fuzzy matching and transliteration-variant detection. Format is implementation-specific but should be documented in gazetteer metadata. WHG v4 uses Symphonym embeddings.
has domain
Name c
has range
string

name typedp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#name_type

Type of name: 'toponym' (place name), 'chrononym' (period/era name), 'ethnonym' (people/ethnic group), 'demonym' (inhabitants), 'odonym' (street/road name), 'hydronym' (water body name). Multiple types possible (e.g., a name that functions as both toponym and ethnonym).
has domain
Name c
has range
string

namespacedp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#namespace

The authority namespace for this Thing (e.g. 'geonames', 'wikidata', 'tgn', 'osm', 'pleiades', 'whg'). Authority-sourced Things carry their origin namespace; contributed Things that cannot be linked to any authority receive the 'whg' namespace.
has domain
Thing c
has range
string

notesdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#notes

Free-text notes providing additional context about this attestation. Can include transcriptions, translations, editorial comments, or other information that doesn't fit structured fields.
has domain
Attestation c
has range
string

open enddp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#open_end

Boolean flag indicating that the end of this interval is deliberately unspecified (not merely unknown). True for ongoing periods like 'Modern era (1800-present)' or situations where the end does not exist. Aligns with PeriodO's OpenEndInterval.
has domain
Timespan c
has range
boolean

open startdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#open_start

Boolean flag indicating that the start of this interval is deliberately unspecified (not merely unknown). True for intervals like 'everything before 1453' or 'prehistory until...'. Distinct from null start_earliest, which indicates unknown start. Aligns with PeriodO's OpenBeginningInterval.
has domain
Timespan c
has range
boolean

ORCIDdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#contributor_orcid

ORCID identifier for person contributors. Can be provided in two formats: 1. Compact format: 0000-0000-0000-0000 (sixteen digits in groups of four) 2. URI format: https://orcid.org/0000-0000-0000-0000 (preferred) The URI format (https://orcid.org/...) is preferred and required for proper linked data representation. ORCID is particular about always including the https:// protocol and domain prefix. While optional in the general ontology, specific implementations (e.g., WHG) may require ORCID for person contributors to ensure proper attribution and citation. ORCID provides persistent identification for researchers, enabling proper credit and reducing name ambiguity.
has domain
Contributor c
has range
string

period labeldp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#period_label

Human-readable label for this period (e.g., 'Byzantine period', 'Han Dynasty', 'Early Bronze Age'). Distinct from authority_title, which may be more formal.
has domain
Period c
has range
string

PeriodO URIdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#period_periodo_uri

Link to a PeriodO period definition for this Period authority. When present, indicates this Period aligns with a standardized PeriodO definition. The PeriodO record provides authoritative temporal bounds, spatial extent, and cultural context. Example: 'https://n2t.net/ark:/99152/p06v8w4rb38'
has domain
Period c
has range
any U R I

PeriodO URIdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#periodo_uri

Link to a PeriodO period definition (https://perio.do/). When a timespan corresponds to a standardized period in PeriodO, this property enables alignment and allows PLATO to inherit PeriodO's temporal bounds, spatial coverage, and cultural context. Example: 'https://n2t.net/ark:/99152/p06v8w4rb38'
has domain
Timespan c
has range
any U R I

precision in kilometersdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#precision_km

Uncertainty radius in kilometers. For point geometries, indicates how far the true location might be from the stated coordinates. For polygons, indicates boundary uncertainty. Can be multiple values for heterogeneous geometries.
has domain
Geometry c
has range
float

precision valuedp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#precision_value

Numeric precision indicator in years. For example, a decade-level precision would have value 10, century-level would be 100. Enables computational comparison of precision across timespans.
has domain
Timespan c
has range
integer

publisherdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#publisher

has domain
Dataset c
has range
string

range constraintdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#relation_range

Valid object type for this relation.
has domain
Relation Type c
has range
string

relation labeldp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#relation_label

Forward label for the relationship (e.g. 'capital_of').
has domain
Relation Type c
has range
string

romanizeddp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#romanized

Romanized (Latin-script) form of the name for searchability and display in contexts requiring ASCII. Should specify transliteration system used via plato:transliteration_system.
has domain
Name c
has range
string

scriptdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#script

ISO 15924 script code (e.g., 'Arab' for Arabic script, 'Latn' for Latin script, 'Hant' for Traditional Han characters). Important for names that may appear in multiple scripts.
has domain
Name c
has range
string

sequencedp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#sequence

Ordering index for attestations in routes or itineraries. Defines the position of this attestation in an ordered sequence. Used when the Thing being attested (via attests_about) is a Route or Itinerary. Lower numbers come first in the sequence.
has domain
Attestation c
has range
integer

similarity scoredp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#similarity_score

has domain
Candidate c
has range
float

source CRSdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#source_crs

Original coordinate reference system. Typically 'EPSG:4326' (WGS84), but may reference historical or custom CRS identifiers for historical maps. Enables proper interpretation of coordinate values.
has domain
Geometry c
has range
string

source labeldp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#source_label

The original label as given in the contributing source, before vocabulary mapping.
has domain
Type c
has range
string

spatial coveragedp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#spatial_coverage

Geographic or cultural region to which this period applies. Free text or URI to a place/region. Useful because periods like 'Medieval' have different temporal bounds in different regions.
has domain
Period c
has range
string

spatial precisiondp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#spatial_precision

Precision qualifier for this geometry: 'exact' (surveyed or GPS), 'approximate' (estimated from maps or descriptions), 'uncertain' (multiple possible locations), 'historical_approximate' (based on historical sources with inherent imprecision). Multiple values possible for heterogeneous geometries.
has domain
Geometry c
has range
string

start earliestdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#start_earliest

The earliest possible start date for this timespan. Together with start_latest, defines the uncertainty range for when the interval began. Use ISO 8601 format (e.g., '1453-05-29') or integer year for year-level precision. May be null for unknown or deliberately open-beginning intervals.
has domain
Timespan c
has range
string

start latestdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#start_latest

The latest possible start date for this timespan. For certain dates, this equals start_earliest. For uncertain dates, defines the end of the uncertainty range for when the interval began.
has domain
Timespan c
has range
string

start precisiondp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#start_precision

Temporal granularity of the start bound. Values: 'year', 'decade', 'century', 'era', 'geological_period'. This describes the resolution of the date specification, distinct from uncertainty (which describes the confidence in that specification).
has domain
Timespan c
has range
string

statusdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#candidate_status

Review status: 'suggested', 'confirmed', 'rejected'.
has domain
Candidate c
has range
string

statusdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#gazetteer_status

Publication status: 'draft' or 'published'.
has domain
Gazetteer c
has range
string

timespan labeldp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#timespan_label

Human-readable label for this timespan (e.g., 'Byzantine period', 'Early Bronze Age', 'Ming Dynasty'). Particularly useful for named periods referenced across multiple attestations.
has domain
Timespan c
has range
string

titledp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#authority_title

has domain
Authority c
has range
string

toponymdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#toponym

The name string itself in its original script. This is the primary property of a Name entity. Required for all Name instances.

has characteristics: functional

has domain
Name c
has range
string

transliteration systemdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#transliteration_system

The transliteration/romanization system used (e.g., 'Pinyin' for Chinese, 'BGN/PCGN' for Arabic, 'ISO 259' for Hebrew, 'Hepburn' for Japanese). Enables proper interpretation and comparison of romanized forms.
has domain
Name c
has range
string

type identifierdp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#type_identifier

URI or identifier in a controlled vocabulary (e.g. AAT).
has domain
Type c
has range
any U R I

type labeldp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#type_label

Human-readable label for this type.
has domain
Type c
has range
string

uncertaintydp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#uncertainty

Epistemic uncertainty: a measure of how precisely the facet value is known, from 0.0 (completely unknown) to 1.0 (no uncertainty). Distinct from fuzziness: uncertainty reflects the limits of evidence, not the inherent vagueness of the referent.
has range
float

uncertainty notedp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#uncertainty_note

Free-text explanation of the nature and source of epistemic uncertainty (e.g. 'manuscript partially illegible', 'coordinates extrapolated from itinerary distances').
has range
string

versiondp back to ToC or Data Property ToC

IRI: https://w3id.org/plato#authority_version

Version identifier for tracking upstream authority updates.
has domain
Authority c
has range
string

Legend back to ToC

c: Classes
op: Object Properties
dp: Data Properties

Acknowledgments back to ToC

The authors would like to thank Silvio Peroni for developing LODE, a Live OWL Documentation Environment, which is used for representing the Cross Referencing Section of this document and Daniel Garijo for developing Widoco, the program used to create the template used in this documentation.