1.1.3. Data Model

        erDiagram
%% Logical entity-relationship diagram of the WHG v4 data model, which is PLATO (https://w3id.org/plato).
%% Relationship labels are PLATO RDF properties. Attribute names are PLATO JSON keys where PLATO JSON has one,
%% otherwise PLATO RDF properties. The id attribute is the node's IRI (JSON @id). This is a model, not a storage layout.

%% The attestation bundle
    ATTESTATION }o--|| SPATIAL_ENTITY : "attests_about"
    ATTESTATION }o--o{ NAME : "attests_name"
    ATTESTATION }o--o{ GEOMETRY : "attests_geometry"
    ATTESTATION }o--o{ TIMESPAN : "attests_timespan"
    ATTESTATION }o--o{ TYPE : "attests_type"
    ATTESTATION }o--o{ PROPERTY_VALUE : "attests_property"

%% Relations, identity and meta-attestations
    ATTESTATION }o--o| SPATIAL_ENTITY : "relates_to"
    ATTESTATION }o--o| RELATION_TYPE : "has_relation_type"
    ATTESTATION }o--o{ IDENTITY_RELATION : "attests_identity"
    IDENTITY_RELATION }o--|| SPATIAL_ENTITY : "identity_subject"
    IDENTITY_RELATION }o--|| SPATIAL_ENTITY : "identity_object"
    ATTESTATION }o--o| ATTESTATION : "meta_attestation_about"

%% Provenance
    ATTESTATION }o--o{ AUTHORITY : "sourced_by"
    ATTESTATION ||--o{ CITATION : "has_citation"
    CITATION }o--|| AUTHORITY : "cites"
    ATTESTATION }o--o| CERTAINTY_LEVEL : "certainty_level"
    ATTESTATION }o--o| CONTRIBUTOR : "contributed_by"

%% The five kinds of Authority
    SOURCE ||--|| AUTHORITY : "subClassOf"
    DATASET ||--|| AUTHORITY : "subClassOf"
    PERIOD ||--|| AUTHORITY : "subClassOf"
    RELATION_TYPE ||--|| AUTHORITY : "subClassOf"
    CERTAINTY_LEVEL ||--|| AUTHORITY : "subClassOf"
    SOURCE }o--o| DATASET : "partOf"
    SOURCE }o--o| TIMESPAN : "source_timespan"
    SOURCE }o--o| SOURCE : "derived_from"
    PERIOD }o--o| TIMESPAN : "has_timespan"
    TIMESPAN }o--o| PERIOD : "relative_to"
    RELATION_TYPE }o--o| RELATION_TYPE : "broader_relation"

%% Gazetteers and gazetteer groups
    GAZETTEER |o--o{ SPATIAL_ENTITY : "contains_entity"
    GAZETTEER |o--o{ ATTESTATION : "contains_attestation"
    GAZETTEER |o--o{ IDENTITY_RELATION : "contains_identity_relation"
    GAZETTEER |o--o{ RELATION_TYPE : "declares_relation_type"
    GAZETTEER }o--o{ GAZETTEER_GROUP : "member_of_group"
    GAZETTEER }o--o| CONTRIBUTOR : "gazetteer_owner"

    SPATIAL_ENTITY {
        iri id "JSON @id"
        string label "display label, not evidence"
        array ccodes "ISO 3166-1 alpha-2, a finding aid"
        string entityIdentifier
        string namespace
    }
    ATTESTATION {
        iri id "JSON @id"
        float certainty "0.0 to 1.0"
        string certaintyNote
        boolean negated
        iri sourceStance
        boolean computed
        int sequence "with MemberOf only"
        iri formStatus
        string notes
        datetime created
        datetime modified
    }
    NAME {
        iri id "JSON @id, optional"
        string toponym "required"
        string language "BCP 47 tag"
        string script "ISO 15924"
        array nameType "toponym, chrononym, ethnonym, ..."
        string romanized
        string transliterationSystem
        string ipa
        string nameEmbedding "WHG uses 128-dimensional Symphonym vectors"
        string sourceLabel
    }
    GEOMETRY {
        iri id "JSON @id, optional"
        json geojson "Point, LineString, Polygon and Multi forms"
        string wkt
        array reprPoint "longitude, latitude"
        array bbox
        string hull "WKT polygon"
        iri role "Extent, FeaturePoint, RepresentativePoint, LabelAnchor, Itinerary"
        array spatialPrecision "exact, approximate, uncertain, historical_approximate"
        array precisionKm
        string sourceCrs
        string sourceLabel
    }
    TIMESPAN {
        iri id "JSON @id, optional"
        string startEarliest "ISO 8601 or signed year"
        string startLatest
        string endEarliest
        string endLatest
        string startPrecision "day, month, year, decade, century, era, geological_period"
        string endPrecision
        int precisionValue "years"
        boolean openStart
        boolean openEnd
        string duration "xsd duration"
        string label
        iri periodoUri
        string edtfString
        string sourceLabel
    }
    TYPE {
        iri id "the dataset's own, never the concept IRI"
        iri identifier "the concept IRI, e.g. AAT or plato TypeRoute"
        iri scheme
        string schemeVersion
        string label "required"
        string sourceLabel
    }
    PROPERTY_VALUE {
        iri property "property IRI in an external vocabulary"
        string value
        iri datatype
        iri unit
        iri valueType
        string label
        string sourceLabel
    }
    IDENTITY_RELATION {
        string identityType "exactMatch, closeMatch, related, unspecified"
        float certainty
        string basis
    }
    CITATION {
        string locator "p. 412, f. 12v"
        iri attributionStatus
        iri citationFunction "a CiTO property"
    }
    AUTHORITY {
        iri id "JSON @id"
        string authority_title "JSON title"
        iri authority_uri "JSON uri"
        string authority_version
        string bibliographic_string "JSON citation"
        iri license "dcterms license, JSON licence"
    }
    DATASET {
        string publisher
    }
    PERIOD {
        string period_label
        iri period_periodo_uri
        string spatial_coverage
    }
    RELATION_TYPE {
        string relation_label
        string inverse_label
        string relation_domain
        string relation_range
    }
    CERTAINTY_LEVEL {
        string authority_title "certain, less certain, uncertain"
    }
    GAZETTEER {
        iri id "JSON @id"
        string title
        string description
        string version
        string status "draft or published"
        iri licence
        array creator
    }
    GAZETTEER_GROUP {
        iri id
    }
    CONTRIBUTOR {
        iri id
        string name
        string orcid
        string role
    }

    

Fig. 1.10 Entity–relationship diagram for the WHG v4 data model.

Note

The model, its formal expression, and its storage. This section describes the WHG v4 data model: SpatialEntities, the Attestations made about them, and the Names, Geometries, Timespans, Types, relations and identity claims that attestations bundle, each resting on Authorities such as Sources and Periods. The model is PLATO, the Place Attestation Ontology, which also defines its JSON and RDF serialisations. The Linked Places Format (LPF) is PLATO’s single-object profile, and remains a supported input and output format.

These pages describe the model, not a storage layout. WHG holds it in PostgreSQL/PostGIS, with Elasticsearch serving search.

• 1.1.3.1. Introduction
  • 1.1.3.1.1. Many names, many shapes, many dates, many sources
  • 1.1.3.1.2. SpatialEntity: where attestations converge
  • 1.1.3.1.3. The Attestation: a bundle of claims with its evidence
  • 1.1.3.1.4. Why attestations rather than fields
  • 1.1.3.1.5. Two attestations in PLATO JSON
  • 1.1.3.1.6. Relations between entities
  • 1.1.3.1.7. Identity between entities
  • 1.1.3.1.8. Authorities: what attestations rest on
  • 1.1.3.1.9. Gazetteers and gazetteer groups
  • 1.1.3.1.10. Meta-attestations
  • 1.1.3.1.11. Where next
• 1.1.3.2. Overview
  • 1.1.3.2.1. Core entities
  • 1.1.3.2.2. At a glance
  • 1.1.3.2.3. SpatialEntity
    • 1.1.3.2.3.1. What kind of thing a SpatialEntity is
    • 1.1.3.2.3.2. What is not a SpatialEntity
  • 1.1.3.2.4. Attestation
  • 1.1.3.2.5. Name
  • 1.1.3.2.6. Geometry
  • 1.1.3.2.7. Timespan
  • 1.1.3.2.8. Type
  • 1.1.3.2.9. PropertyValue
  • 1.1.3.2.10. Qualifying a facet
  • 1.1.3.2.11. Authorities
  • 1.1.3.2.12. Gazetteer and GazetteerGroup
  • 1.1.3.2.13. Identity
  • 1.1.3.2.14. Meta-attestations
  • 1.1.3.2.15. Contributors
  • 1.1.3.2.16. Lifecycle
  • 1.1.3.2.17. Design rationale
  • 1.1.3.2.18. Next steps
• 1.1.3.3. Attestations and Relations
  • 1.1.3.3.1. What an attestation bundles
    • 1.1.3.3.1.1. Example: Constantinople in the Notitia Urbis
  • 1.1.3.3.2. Qualifications: certainty, fuzziness and precision
  • 1.1.3.3.3. Denial and the source’s stance
  • 1.1.3.3.4. Sources and citations
  • 1.1.3.3.5. Attribution
  • 1.1.3.3.6. Computed values
  • 1.1.3.3.7. Relations
    • 1.1.3.3.7.1. Relation types
    • 1.1.3.3.7.2. Example: containment
    • 1.1.3.3.7.3. Example: membership and sequence
    • 1.1.3.3.7.4. Associations with people, objects and events
  • 1.1.3.3.8. Identity
    • 1.1.3.3.8.1. Candidates, clusters and loci
  • 1.1.3.3.9. Meta-attestations
    • 1.1.3.3.9.1. Which to use
  • 1.1.3.3.10. Attestations about other Gazetteers’ places
    • 1.1.3.3.10.1. Place collections
  • 1.1.3.3.11. Reading attestations
• 1.1.3.4. Vocabularies
  • 1.1.3.4.1. Name types
  • 1.1.3.4.2. Place types
    • 1.1.3.4.2.1. GeoNames feature classes
    • 1.1.3.4.2.2. Kinds of spatial entity
  • 1.1.3.4.3. Temporal precision
  • 1.1.3.4.4. Spatial precision and geometry roles
    • 1.1.3.4.4.1. Relative position
  • 1.1.3.4.5. Certainty, fuzziness and the source’s stance
    • 1.1.3.4.5.1. Reading the source
  • 1.1.3.4.6. Kinds of authority
  • 1.1.3.4.7. Citation functions
  • 1.1.3.4.8. Meta-attestation types
  • 1.1.3.4.9. Relation types
  • 1.1.3.4.10. Identity and matching
  • 1.1.3.4.11. Gazetteers and contributors
• 1.1.3.5. Routes, Itineraries, Networks, Groups and Periods
  • 1.1.3.5.1. The building blocks
    • 1.1.3.5.1.1. Typing: routes, itineraries, networks and segments
    • 1.1.3.5.1.2. Membership and sequence: MemberOf
    • 1.1.3.5.1.3. Connections and direction: ConnectedTo and LeadsTo
    • 1.1.3.5.1.4. Segments: BeginsAt, EndsAt and HasEnd
    • 1.1.3.5.1.5. Figures on links: PropertyValues
    • 1.1.3.5.1.6. Computed values: plato:computed
  • 1.1.3.5.2. Route
    • 1.1.3.5.2.1. Routes within routes
    • 1.1.3.5.2.2. Branches and alternatives
    • 1.1.3.5.2.3. Unknown order
    • 1.1.3.5.2.4. Two sources, two orders
  • 1.1.3.5.3. Itinerary
  • 1.1.3.5.4. Network
    • 1.1.3.5.4.1. Physical networks: segments
    • 1.1.3.5.4.2. Relational networks: connections with figures
  • 1.1.3.5.5. Gazetteer groups
  • 1.1.3.5.6. Periods
  • 1.1.3.5.7. Computed extents
  • 1.1.3.5.8. On place pages
    • 1.1.3.5.8.1. Associations: places in the histories of people, objects and events
• 1.1.3.6. Contributions: What Arrives and What It Becomes
  • 1.1.3.6.1. Formats WHG accepts
  • 1.1.3.6.2. What a contribution becomes
    • 1.1.3.6.2.1. A Gazetteer
    • 1.1.3.6.2.2. What a contribution does not become
  • 1.1.3.6.3. From each format
    • 1.1.3.6.3.1. Map your Data
    • 1.1.3.6.3.2. Linked Places Format
    • 1.1.3.6.3.3. PLATO JSON and spreadsheet tables
  • 1.1.3.6.4. Routes, itineraries and networks
  • 1.1.3.6.5. Linking to places WHG already holds
  • 1.1.3.6.6. Geometry is always attributed
  • 1.1.3.6.7. Gazetteer groups
  • 1.1.3.6.8. Place collections
  • 1.1.3.6.9. Changing a contribution
    • 1.1.3.6.9.1. Draft and published
    • 1.1.3.6.9.2. Places are not deleted or merged
    • 1.1.3.6.9.3. A revised upload
    • 1.1.3.6.9.4. Corrections from others
  • 1.1.3.6.10. Taking data out
    • 1.1.3.6.10.1. DOIs
• 1.1.3.7. RDF Representation
  • 1.1.3.7.1. What WHG serves, and how
    • 1.1.3.7.1.1. From PLATO JSON to RDF
  • 1.1.3.7.2. Namespaces
  • 1.1.3.7.3. The classes and properties
  • 1.1.3.7.4. An attestation in Turtle
    • 1.1.3.7.4.1. Names
    • 1.1.3.7.4.2. Geometries
    • 1.1.3.7.4.3. Timespans
    • 1.1.3.7.4.4. Types
  • 1.1.3.7.5. Relations
  • 1.1.3.7.6. Denials
  • 1.1.3.7.7. Identity
  • 1.1.3.7.8. Meta-attestations
  • 1.1.3.7.9. Provenance
  • 1.1.3.7.10. Querying with SPARQL
    • 1.1.3.7.10.1. 1. The names of a place, with their dates and sources
    • 1.1.3.7.10.2. 2. Routes, itineraries, networks and segments
    • 1.1.3.7.10.3. 3. The members of an itinerary, in order
    • 1.1.3.7.10.4. 4. Meta-attestations: what comments on what
    • 1.1.3.7.10.5. 5. Identity claims, and whether they were denied
    • 1.1.3.7.10.6. 6. The current state: attestations not withdrawn or replaced
  • 1.1.3.7.11. Checking RDF
  • 1.1.3.7.12. See also
• 1.1.3.8. Use Cases
  • 1.1.3.8.1. Finding a place as it was named at the time
  • 1.1.3.8.2. Dating by period
  • 1.1.3.8.3. Weighing sources that disagree
  • 1.1.3.8.4. Containment: what lay within what, and when
  • 1.1.3.8.5. Reconciling a list of place names
  • 1.1.3.8.6. One place in many gazetteers: clusters and loci
  • 1.1.3.8.7. Routes, journeys and networks
  • 1.1.3.8.8. Places in the histories of people, objects and events
  • 1.1.3.8.9. Contributing and curating
  • 1.1.3.8.10. Citing a place in a gazetteer that changes
  • 1.1.3.8.11. How this differs from other resources
• 1.1.3.9. Summary
  • 1.1.3.9.1. The idea in one paragraph
  • 1.1.3.9.2. Key entities
  • 1.1.3.9.3. Attestation
  • 1.1.3.9.4. Relations
  • 1.1.3.9.5. Identity
  • 1.1.3.9.6. Meta-attestations
  • 1.1.3.9.7. Gazetteers, collections, groups and periods
  • 1.1.3.9.8. Computed values
  • 1.1.3.9.9. Vocabularies
  • 1.1.3.9.10. Formats and RDF
  • 1.1.3.9.11. Storage
  • 1.1.3.9.12. What it is for