Open Property Data Association
Smart Property Data Trust Framework
Become a member Join a working group

    Vocabularies (SKOS)

    The 48 SKOS concept schemes (319 concepts in total) that carry every coded value-space in the ontology — from the SPARQL-extracted ontology model. Under the classification doctrine (ODR-0027), these schemes do the work that subclass trees do in lesser models: every enumeration, status set, and kind-discriminator is a skos:ConceptScheme referenced by a coded value — never an owl:oneOf bag and never a subclass enumeration. Each scheme links to its own page with its full concept membership.

    The /pdtf/scheme/ kind-split (ADR-0006)

    The concept schemes deliberately live under a separate namespace segment, https://opda.org.uk/pdtf/scheme/ (prefix opda-v:), distinct from the flat term namespace https://opda.org.uk/pdtf/ (prefix opda:). The reason (ADR-0006, directing-authority ruling 2026-06-02) is collision-avoidance: a property such as opda:role at …/pdtf/role must not collide with the Participant Role scheme — so the scheme resolves at …/pdtf/scheme/role and its members at …/pdtf/scheme/role/Buyer. A few schemes minted in the flat term namespace (e.g. BoundedContextScheme) resolve at …/pdtf/{Name} instead — the link target below reflects each scheme's actual IRI.

    UFO category

    Schemes no longer carry opda:ufoCategory. The register-deference value-space tags (Quale-in-Region etc.) were split off the predicate — they are value-space shape, not UFO categorial work (ODR-0030 Rule 2 / ODR-0031). The opda:ufoCategory facet is now reserved for the nine UFO meta-categories of the OWL classes, as an inert, annotation-graph-only documentary annotation (UFO-informed, not UFO-grounded).

    Scheme index · 48 schemes · 319 concepts

    SchemeConceptsDefinition
    ActionAlertRatingScheme
    Action Alert Rating    		 5 The value-space of opda:actionAlertRating on an opda:RiskAssessment: an ordinal 1–5 scale where 1 is Green (lowest risk) and 5 is Red (highest risk). Derived from the data dictionary's actual actionAlertRating integer leaf + its title "Action alert rating (1 is Green, 5 is Red)" (ODR-0008d Rule 4).
    AddressVariantScheme
    Address Variant    		 3 Quality Values for the variant under which an Address is presented (marketing, title, inspire, postal). Each variant particularises an underlying Address Substance Kind per ODR-0015 §Q1.
    AttachmentStatusNotApplicableScheme
    Attachment Status (with Not applicable)    		 3 Status of a supporting document attached to a disclosure answer, admitting non-applicable as a third option (Attached / Not applicable / To follow).
    AttachmentStatusScheme
    Attachment Status    		 2 Status of a supporting document attached to a disclosure answer: provided now, or to follow.
    BoundaryResponsibilityScheme
    Boundary Responsibility    		 4 Which party is responsible for a legal boundary of the property (the Seller, shared, the neighbour, or not known).
    BoundedContextScheme 6 The six industry bounded contexts of the UK PDTF, each owning a SHACL overlay profile (ODR-0010). Domain-term membership in a context is a derived, on-demand query (opda:servesContext per ODR-0020), never hand-authored except per ODR-0019 Rule 8.
    BroadbandConnectionTypeScheme
    Broadband Connection Type    		 5 Classification of a Property's broadband connection type (None / ADSL copper wire / Cable / FTTC (Fibre to the Cabinet) / FTTP (Fibre to the Premises)).
    BuiltFormScheme
    Built Form    		 5 Classification of a Property's structural built-form (detached, semi-detached, terraced, etc.).
    CentralHeatingFuelTypeScheme
    Central Heating Fuel Type    		 6 Classification of the fuel used by a Property's central heating system.
    ChargePaymentStatusScheme
    Charge Payment Status    		 4 Payment status of a managed-area charge (due, completed but unpaid, anticipated, or not applicable).
    ConstructionTypeScheme
    Construction Type    		 5 Classification of a Property's standard-form construction type (Brick and block / Steel frame / Timber frame / Insulated concrete framework / Structural insulated panel (SIP)).
    CouncilTaxBandSchemeEW
    Council Tax Band (England & Wales)    		 8 Valuation Office Agency banding for England & Wales (Bands A–H) assigned to each domestic property for council tax calculation.
    CouncilTaxBandSchemeScotland
    Council Tax Band (Scotland)    		 9 Scottish Assessors Association banding for Scotland (Bands A–I) assigned to each domestic property for council tax calculation. Band I is Scotland-specific.
    CurrencyScheme
    Currency    		 3 The currency of an opda:MonetaryAmount — an ISO-4217 alpha-3 currency code. Seeded with the currencies occurring in UK property-pack data (GBP / EUR / USD); extensible to the full ISO-4217 code space as data requires.
    CurrentEnergyRatingScheme
    Current Energy Rating    		 7 EPC current energy rating banding (A–G) published by DESNZ (Department for Energy Security and Net Zero) for residential properties in England & Wales.
    DeedSupplyStatusScheme
    Deed Supply Status    		 3 Supply status of a requested deed or document: attached now, to follow, or lost.
    EvidenceMethodScheme
    Evidence Kind    		 3 The OIDC4IDA `evidence.type` kinds of identity evidence (Document, Electronic-Record, Vouch) — the governed facet for opda:evidenceType, bound to the evidence subclasses by skos:exactMatch (ODR-0011 §8a).
    FeeTypeScheme
    Fee Type    		 4 Type of recurring fee a payee collects for a managed freehold or commonhold (service charges, ground rent, administration fees, or all).
    FittedOrFreestandingScheme
    Fitted or Freestanding    		 2 Whether a kitchen appliance is fitted (built in) or freestanding (movable).
    FixtureItemScheme
    Fixture Item    		 89 Controlled list of the fixtures-and-fittings checklist *items* (boiler/immersion heater, radiators, curtains, carpets, kitchen appliances, garden items, etc.) a seller discloses for a sale. Items are Objects/Kinds; their inclusion in a given sale is a Mode/Relator of the transaction (council-reserved, ODR-0023 R4) and is NOT a property of any item concept.
    HeatingTypeScheme
    Heating Type    		 4 Classification of a Property's overall heating-system arrangement (central, communal, room-only, or none).
    InclusionScheme
    Inclusion (Included / Excluded)    		 2 Whether a free-text 'other item' is included in or excluded from the sale (binary variant, no 'None' option).
    InclusionStatusScheme
    Inclusion Status    		 3 Whether a fixtures-and-fittings item is included in, excluded from, or absent from (None) the sale. NOTE: this is the *value-space* only; the inclusion-status property that ranges over it is council-reserved (ODR-0023 R4) and is NOT minted here.
    ManagedAreaResponsibilityScheme
    Managed-Area Responsibility    		 6 Which party deals with the day-to-day maintenance of a managed area. The canonical six-value superset; per-form subsets (e.g. without 'the Lessees', or without 'Rentcharge Owner') are `sh:in` restrictions in the overlay profile, NOT separate schemes (ODR-0011 §1a).
    MilestoneKindScheme
    Milestone Kind    		 5 Method/plan codes for the procedural milestones authorising stages of a Transaction Activity (instruction → offerAccepted → exchange → completion → registration).
    OffMainsDrainageSystemTypeScheme
    Off-Mains Drainage System Type    		 6 Classification of a Property's off-mains drainage system (SuDS / Septic tank / Cesspit / Sewerage treatment plant / Other / Not known).
    OfstedRatingScheme
    Ofsted Rating    		 5 Ofsted school-inspection rating of a nearby school (opda:NearbyFacility school band): Outstanding / Good / Requires Improvement / Inadequate / Other.
    OwnershipTypeScheme
    Ownership Type    		 5 Classification of a legal estate's ownership structure (Freehold, Managed Freehold, Commonhold, Leasehold, Other).
    OwnerTypeScheme
    Owner Type    		 2 Substance Kind labels discriminating Private individual (opda:Person) from Organisation (opda:Organisation) as legal owner. Distinct from RoleScheme (transactional role) and TenureKindScheme (sub-Kind of LegalEstate).
    ParticipantStatusScheme
    Participant Status    		 4 Phase labels for the lifecycle of a Participant Substance Kind.
    PerilScheme
    Environmental Peril    		 12 The 12 environmental / local-authority search perils a property's authority-retrieved risk assessments (opda:RiskAssessment) are individuated by. Each peril is a dereferenceable concept governed by a named data authority (ODR-0008d Rule 2); the peril is NEVER an opaque string and NEVER an rdfs:subClassOf hierarchy (a delimited value-space is a scheme, not a class tree).
    PriceQualifierScheme
    Price Qualifier    		 9 Qualifier on a Property's marketed asking price (Price / Fixed price / Guide price / Offers in excess of / Offers in region of / Offers over / Offers invited / Sale by tender / From).
    PropertyTypeScheme
    Property Type    		 6 Substance Kind labels for the physical-form kind of a Property (House / Bungalow / Park home / Flat / Maisonette / Other). Distinct from BuiltFormScheme which carries the structural Quale (Detached / Semi-detached / Terrace).
    RoadAdoptionStatusScheme
    Road Adoption Status    		 4 Maintenance-responsibility status of an abutting road or footway: publicly maintained, private, subject to a section-38 agreement, or unchecked.
    RoleScheme
    Participant Role    		 12 Role labels for the anti-rigid Roles a Person/Organisation plays as a Participant in a Transaction Relator.
    SchoolTypeScheme
    School Type    		 5 The value-space of opda:schoolType on opda:NearbyFacility — the band of a nearby school (College / Nursery / Primary / Secondary / Private). Replaces the five range-less generic object properties the council rejected (session-028 Q1); minted from the schoolType structural band set, not a data-dictionary enum.
    SellersCapacityScheme
    Seller's Capacity    		 6 Method/plan codes for the capacity under which a Seller is authorised to act in a sale.
    TenureKindScheme
    Tenure Kind    		 3 Substance Kind labels for tenure (Freehold, Leasehold, Commonhold). Each member binds to its corresponding OWL sub-class via `skos:exactMatch` per ODR-0011 §8a Substance Kind label cross-scheme consistency check (NEVER `owl:sameAs`).
    TransactionStatusScheme
    Transaction Status    		 5 Phase labels for the lifecycle of a Transaction Substance Kind, tracking the five canonical phases ADR-0010 names (Listed → Offered → Accepted → Exchanged → Completed).
    TransportTypeScheme
    Transport Type    		 10 Classification of a nearby transport node (opda:NearbyFacility transport band): Local connection / Ferry terminal / Bus stop/station / National rail station / Trunk road/motorway / Airport / Helipad / Tramway / Underground/Subway / Other.
    UFOCategoryScheme
    UFO Category Scheme    		 9 The nine UFO foundational meta-categories OPDA classifies its classes under. Each concept carries its OntoClean signature and a skos:closeMatch to the corresponding gUFO type where one exists. Referenced-not-imported; never reasoned over (ODR-0031 R2).
    UnitOfAreaScheme
    Unit of Area    		 2 Unit in which an internal floor area is expressed (square metres or square feet).
    UtilityConnectionStatusNotKnownScheme
    Utility Connection Status (with Not known)    		 4 Mains-utility connection status admitting unknown-to-Seller as a fourth option (Yes / No / To be connected / Not known).
    UtilityConnectionStatusScheme
    Utility Connection Status    		 3 Whether a mains utility (electricity, gas, water, drainage) is connected, not connected, or to be connected.
    YesNoNotApplicableScheme
    Yes/No/Not applicable    		 3 Mode label register for BASPI5 questions admitting non-applicable as a third option (Yes / No / Not applicable).
    YesNoNotKnownScheme
    Yes/No/Not known    		 3 Mode label register for BASPI5 questions admitting unknown-to-Seller as a third option (Yes / No / Not known).
    YesNoNotRequiredScheme
    Yes/No/Not required    		 3 Mode label register for BASPI5 questions admitting not-required as a third option (Yes / No / Not required).
    YesNoScheme
    Yes/No    		 2 Binary register for affirmative/negative answers to BASPI5 discriminator questions (Yes / No).

    Browse per-concept

    Each concept has its own /pdtf page (linked from its scheme above). For an interactive cross-scheme browser — concept hierarchies, search — the bake-off (ADR-0041) renders the schemes with two tools:

    RenderingWhat it givesOpen
    Skosmos The dedicated SKOS browser — schemes list, concept hierarchies, search. Runs over the local Fuseki via make serve-data + make skosmos (localhost-only, ADR-0041 §B2); the static schemes list is the always-available fallback. Skosmos browser ↗ (localhost:9090 — needs make serve-data + make skosmos)
    Static schemes list ↗
    Ontospy Multi-page browser with a per-scheme / per-concept page set (e.g. class-skosconceptscheme.html). Ontospy SKOS pages ↗

    Why coded schemes carry the classification: the classification doctrine (ODR-0027). The OWL classes these values attach to are on Classes; the properties that reference them are on Properties. Full index: Index & glossary.

    Comments

    Loading comments…