Public Transportation Use Cases

Public Transportation Use Cases
Proposal status:	Inactive (inactive)
Proposed by:	JaLooNz
Draft started:	2017-12-31

Proposal

This proposal is to document the minimal and recommended features required for public transportation mapping (that is required for rendering and routing) via use cases. This is intended to be a supplement to the Public Transport tagging proposal to clarify what are the minimum mandatory and recommended optional features that should be captured in a route relation, taking into account the ease of maintaining route relations (which can number into thousands for a moderately dense public transport network in a city). This proposal also documents what is in use by various public transport map renderers and what is required for routing calculations to be quickly performed. Information on recent proposals such as Proposed features/PTv2 Improvements wrt Rapid Transit are also included where possible.

Rationale

The current proposals only deals primarily with what features are available for mapping, and does not really describes what each feature is used/can by used by map renderer or routing systems. This results in patchwork of Public Transportation route mapping and causes unnecessary complexity in mapping route relations.

Use Case (with Examples)

Rendering

OSM Cartomap

Andy Allan PTMap

Route relation for Rail (See Blue highlights on images)

Feature Reference	Feature Tag	Feature Tag (PTv1)	Feature Tag (PTv2)	Route Relation (PTv1)	Route Relation (PTv2)	Renderer	Routing	Comment	Recommendation
Station Node		railway=station	public_transport=station	Yes, role=stop		Yes, as named point.	Yes, as stop.	A single station node representing a station with multiple lines in the immediate vicinity. This station node should not be applied to stop areas as it may differ significantly from the centroid of the stop area.	Mandatory
Track		railway=rail		Yes, no role	Yes, no role	Yes, as rendered track.	Yes, for calculating distance and traveling time from station-to-station.		Optional (Recommended)
Point on track.			public_transport=stop_position	Yes, role=stop	Yes, role=stop	Not used.	Not used.	There is really no need for the stop position beyond this being an optimisation to reduce the calculations of the stop point.	Optional
/ Waiting area.		highway=platform	public_transport=platform	Yes, role=platform	Yes, role=platform	Yes, as line/area.	Not used.		Optional
Station building	building=train_station					Yes, as building area.	Not used.	This is the station building. Do not apply railway=station or public_transport=station onto the building.	Optional
Stop Area			public_transport=stop_area			Not used.	There may be limited use for routing, but needlessly increases the complexity due to increased traversal required.	This captures all elements of a stop. This relation is not useful beyond organisation of stop elements, and to reduce tag duplication especially on multilingual names. Users are recommended to keep important information on the railway=station or public_transport=station tag instead.	Optional

Comments

Please comment on the discussion page.