Overlay profiles

OPDA’s foundation + module shape-graph leaves per-form cardinality, per-form enumeration subsets, and per-form UI rendering to overlay profiles. Each profile is a separate SHACL graph that composes over the foundation + module TBox + base shapes per ODR-0010.

Three-rule interface contract

Per ODR-0010 §Q6, every overlay profile MUST satisfy three rules enforced by foundation meta-shapes:

Rule	Enforced by	Semantics
1 — `sh:in` semantics	`opda:ShInSemantics_MetaShape`	Overlay `sh:in` MUST be a subset of base scheme members
2 — Violation floor	`opda:ShViolationFloor_MetaShape`	Overlay cannot downgrade base `sh:Violation` severity
3 — No-identity-override	`opda:NoIdentityOverride_MetaShape`	Overlay cannot suppress Kind’s identity-key

CI-enforced by opda-gen ci-profile-contract per ADR-0013.

Profile catalogue

Profile	Version	Authority	Status
`opda:Baspi5OverlayProfile`	5.0.3	BASPI (British Association of Surveyors Property Information)	MVP gate (ODR-0010 §Q7)

Future profiles (planned, not yet emitted):

Mortgage-lender overlay (lender-specific data requirements)
HMLR-publication overlay (HMLR-public data subset)
Insurer overlay (insurance-eligibility data)

ValidationContext reification

Per ODR-0010 §Q1 (Guarino withdrawal condition), every profile is reified as an opda:ValidationContext instance carrying five properties:

Property	Value
`opda:profileURI`	The profile’s URI (e.g. `<https://opda.org.uk/pdtf/shape/profiles/baspi5>`)
`opda:requires`	The Kind classes the profile constrains
`opda:overlaysContext`	The base context the profile overlays (typically `<https://opda.org.uk/pdtf/shape/profiles/foundation>`)
`opda:sourcedFrom`	The external authoring source (e.g. BASPI form URL)
`opda:formVersion`	The form version (e.g. “5.0.3”)

This reification converts conditionality from “required (depending)” to “required relative to a named, dereferenceable context” — discharging Guarino’s withdrawal condition at S010.

DASH UI integration

Per ODR-0010 §Q4, overlay shapes carry DASH (Data Shapes) editor + viewer predicates:

dash:editor — dash:EnumSelectEditor (for sh:in enum), dash:TextFieldEditor (for literals), dash:DetailsEditor (for nested objects)
dash:viewer — dash:LabelViewer, dash:LiteralViewer, dash:URIViewer

These enable TopBraid Composer / DASH-aware tooling to render appropriate form widgets.

Property groups

Overlay profiles MAY declare sh:PropertyGroup instances to group related property shapes for UI rendering. BASPI5 declares 9 groups (Address, Built form, Completion, Drainage, Energy, Environmental, Heating, Ownership, Participants) with sh:order for sequencing.