GMEOW Accessibility Module

• IRI: https://blackcatinformatics.ca/gmeow/slices/accessibility
• Tier: extension
• Group: extensions

What This Slice Covers

This slice owns 19 terms and contributes 16 mapping or projection rows. Use it when its terms match the native fact you want to preserve; use the linkage tables to see how those facts leave GMEOW for consumer vocabularies.

Dependencies

• gmeow:slices/kernel
• gmeow:slices/places

Consumers

• Accessibility facets over places and routes; the schema.org accessibility projection.

Local Map

Examples

Location Access

• Source: slices/extensions/accessibility/examples/location-access.ttl
• GMEOW terms: gmeow:AccessibilityAssertion, gmeow:Person, gmeow:Place, gmeow:assertionFacet, gmeow:assertionPolarity, gmeow:assertionSubject, gmeow:facetStepFree, gmeow:facetVisual, gmeow:facetWheelchair, gmeow:hasAccessibilityFeature

# SPDX-FileCopyrightText: 2026 Blackcat Informatics® Inc. <paudley@blackcatinformatics.ca>
# SPDX-License-Identifier: CC-BY-4.0
#
# Worked example: accessibility as MATCHABLE facets. One open vocabulary of
# gmeow:AccessibilityFacets (wheelchair, step-free, visual, auditory, cognitive …)
# is used across three relations: what a location HAS
# (gmeow:hasAccessibilityFeature), what it lacks as a gmeow:hasBarrier, and what an
# agent NEEDS (gmeow:hasAccessibilityNeed). Because need and feature draw on the
# same vocabulary, "Dana needs wheelchair access" and "the library has wheelchair
# access" MATCH directly. A reified gmeow:AccessibilityAssertion records who
# claims which facet, with a gmeow:assertionPolarity (feature / barrier / limited).
@prefix gmeow: <https://blackcatinformatics.ca/gmeow/> .
@prefix ex:    <https://blackcatinformatics.ca/gmeow/examples/accessibility/> .

# --- A location with a feature and a barrier (facets are per-location facts).
ex:library a gmeow:Place ;
    gmeow:name                    "City Library"@en ;
    gmeow:hasAccessibilityFeature gmeow:facetWheelchair ;
    gmeow:hasBarrier              gmeow:facetVisual .

# --- An agent's need, drawn from the SAME facet vocabulary → directly matchable
#     against the library's feature.
ex:dana a gmeow:Person ;
    gmeow:name               "Dana Reyes"@en ;
    gmeow:hasAccessibilityNeed gmeow:facetWheelchair .

# --- A reified assertion: a surveyor claims the library is step-free (a feature).
ex:assertion a gmeow:AccessibilityAssertion ;
    gmeow:assertionSubject  ex:library ;
    gmeow:assertionFacet    gmeow:facetStepFree ;
    gmeow:assertionPolarity gmeow:polarityFeature .

Terms

Classes

Properties

Individuals

Linkages

• Rows: 16
• Projection profiles: schema-org
• External vocabularies: fhir, schema, sosa

Guide

Accessibility — features, barriers, and needs as co-equal facets

Slice: https://blackcatinformatics.ca/gmeow/slices/accessibility · tier: extension Whether an entity can reach or use a location under constraints — said honestly, per facet.

Most vocabularies flatten accessibility to a boolean (wheelchairAccessible true). GMEOW refuses the collapse: accessibility is a family of orthogonal dimensions — wheelchair, step-free, visual, auditory, cognitive, clearance, life-support — and each dimension is an open value facet (Principle 9: individuals, never subclasses; a new facet is data, not a schema change). Features, barriers, and needs are co-equal: there is no "primary need", and a location may honestly carry both a feature and a barrier for the same facet (a ramp at the front entrance, stairs at the side). The flat shortcuts cover the 80 % case; promote to a reified AccessibilityAssertion when provenance, confidence, temporal scope, or suppression matter (Principle 10: suppression is displayable false, never deletion). The slice is part of the the design Location-as-reference-frame design.

Its Principle-15 consumer, declared in the manifest: accessibility facets over places and routes, and the schema.org accessibility projection — every term here either drives accessible-route solving or down-projects to schema:accessibilityFeature and kin.

The value vocabularies

gmeow:AccessibilityFacet

The dimension being asserted — the seeds are facetWheelchair, facetStepFree, facetVisual, facetAuditory, facetCognitive, facetClearance, facetLifeSupport. An open vocabulary (Principle 9): a facet not among the seeds is a fresh individual with a label, never a subclass. Facets are the shared currency of all three shortcut properties and of the reified assertion.

gmeow:AccessibilityPolarity

The sign of a reified claim: polarityFeature (the subject provides the facet), polarityBarrier (it impedes it), or polarityLimited (it provides it under some conditions but not all). Polarity exists only on the reified form — the flat shortcuts encode polarity in the property name.

The flat shortcuts (the 80 % case)

gmeow:hasAccessibilityFeature

Location → AccessibilityFacet: the location positively provides the facet. Non-functional — a location may support many facets, and may simultaneously carry hasBarrier for the same facet under different local conditions. The properties are deliberately not disjoint; disambiguation belongs to the reified form, not to schema exclusions.

gmeow:hasBarrier

Location → AccessibilityFacet: the location impedes the facet. The honest negative — a barrier is asserted data, not the mere absence of a feature (open world: silence means unknown, hasBarrier means known impediment).

gmeow:hasAccessibilityNeed

Entity → AccessibilityFacet: what an entity requires in order to reach or use a location. Needs are co-equal facets (Principle 9) — all asserted needs coexist. This is the demand side that the solver matches against the supply side (features/barriers) when computing accessible routes.

The reified form (promote when metadata matters)

gmeow:AccessibilityAssertion

A gufo:Relator-grounded claim that a location or connection (the connectivity slice's Connection is an admissible subject) has a feature, barrier, or limited status for a facet. Bears vantage, confidence, temporal scope, and suppression (displayable false — Principle 10). Promote here whenever the claim itself must be a node — "accessible according to the 2024 city audit, disputed by the user survey".

gmeow:assertionSubject · gmeow:assertionFacet · gmeow:assertionPolarity

The three functional role properties of the relator: one subject, one facet, one polarity per assertion. Relator mediation is axiomatized (someValuesFrom restrictions, EL-safe) so ELK sees the doctrine; closed-world cardinality is SHACL's job.

Solver layer & bridges

Accessible routes are computed, never asserted (Principle 12): the connectivity slice declares the routeKindAccessible route kind, and the solver layer walks the connection graph matching hasAccessibilityNeed against features and barriers to produce a path. The OWL core only models the inputs.

Dependencies

Depends on kernel and places (the Location domain of the shortcuts). Sibling to connectivity — mutually independent extensions joined only at the solver layer and at routeKindAccessible (slice-dependency doctrine refactor keeps that value individual beside its value class, in connectivity).