Model station entrances as first-class transit infrastructure and routing targets

[Medformatik]

Problem

A route to a large station is not complete when it ends at the station centroid or a generic platform. Users need the correct entrance or exit, including accessible choices, and routing/search need a stable model connecting entrance data to stations, platforms, levels, and the street network.

Current state

• TransitStopInfrastructure models parent stops, child stops, platforms, accessibility, fare zones, and park-and-ride.
• Entur, Swiss open-transport-data, and MOTIS providers expose useful stop/platform structure.
• The map renders selected stop infrastructure.
• There is no generic entrance entity, entrance lookup service, or entrance routing target.

Proposed solution

Extend the shared contract with a source-aware entrance model and deterministic PostGIS resolution pipeline. Prefer provider/feed pathways, then explicit station relations, parent/child roles, station-area containment/adjacency, and finally a bounded spatial fallback with confidence.

Acceptance criteria

• The contract represents entrance ID, geometry, station relationship, name/ref, level, accessibility, restrictions, source, and confidence.
• Provider adapters can supply entrances without losing attribution.
• PostGIS tables/indexes support the documented resolution tiers at regional scale.
• Resolution is deterministic, reports the matched tier, and does not merge nearby unrelated stations.
• OSM subway/railway entrances and relevant public-transport relations have complex-interchange fixtures.
• Accessible routing can require a compatible entrance and reports when none is known.
• Directions can terminate at an entrance and include access/egress walking legs.
• The map renders/selects entrances without regressing platforms or stop hierarchy.
• Search returns entrances with enough station context to be understandable.
• Quality metrics cover unmatched, ambiguous, fallback, and inaccessible entrances.

Alternatives considered

Ordinary POIs lose station topology and accessibility. Always choosing the closest entrance fails for divided stations and restricted entrances.

Area

Transit contracts, PostGIS, providers, routing, map UI.

Dependencies and non-goals

Indoor turn-by-turn is out of scope. This model should feed arrival handoff and later improve reachability calculations.