Boarding Locations should support more tags

[Brickblock1]

Is your feature request related to a problem? Please describe.

Currently OTP supports these tags for linking Boarding Locations:
public_transport=platform
highway=bus_stop
railway=tram_stop
railway=station
railway=halt
amenity=bus_station
amenity=ferry_terminal
railway=platform (undocumented)

This list works well when the osm data uses PTv2 tagging but linking becomes troublesome in places where PTv2 is not used. Notible examples of places where PTv2 is not used are Norway and the area around Stockholm.

Most notible is the lack of highway=platform from this list which is a better candidate for linking as it is more often connected to the street grid than highway=bus_stop and better represents the waiting area.

Goal / high level use-case

Be able to use Boarding Location linking for bus stops in Stockholm where stop locations in GTFS/NeTEx can be quite inaccurate.

Describe the solution you'd like

Add highway=platform and public_transport=station to the list of supported tags.
Look at removing railway=tram_stop as it is analogous to public_transport=stop_position which is explicitly not supported.

Describe alternatives you've considered

1. Adding public_transport=platform before loading the OSM data into OTP.
   This is rather cumbersome and adds a barrier for beginners to overcome.
2. Not linking GTFS/NeTEx to the platform but rather the highway=bus_stop node.
   This is not going to work nearly as well since highway=bus_stop is not universally expected to be connected to the street grid.

Additional context

Image from PTSA showing area where PTv2 tagging isn't used.

It is very unlikely that this tagging convention of not using PTv2 for bus stops will change in the future. (users are actively removing PTv2 tags)

[leonardehrenfried]

highway=platform, while not the totally recommended way of tagging platforms (but in OSM which tag really is?), seems fine for me to support. I would welcome a PR for this.

If you're a Java developer, the code in question is here:

OpenTripPlanner/application/src/main/java/org/opentripplanner/osm/model/OsmWithTags.java

Lines 565 to 600 in 713143b

	/**
	* Is this a public transport boarding location where passengers wait for transit and that can be
	* linked to a transit stop vertex later on.
	* <p>
	* This intentionally excludes railway=stop and public_transport=stop because these are supposed
	* to be placed on the tracks not on the platform.
	*
	* @return whether the node is a place used to board a public transport vehicle
	*/
	public boolean isBoardingLocation() {
	return (
	isTag("highway", "bus_stop") ||
	isTag("railway", "tram_stop") ||
	isTag("railway", "station") ||
	isTag("railway", "halt") ||
	isTag("amenity", "bus_station") ||
	isTag("amenity", "ferry_terminal") ||
	isPlatform()
	);
	}
	/**
	* Determines if an entity is a platform.
	* <p>
	* However, they are filtered out if they are tagged usage=tourism. This prevents miniature tourist
	* railways like the one in Portland's Zoo (https://www.openstreetmap.org/way/119108622)
	* from being linked to transit stops that are underneath it.
	**/
	public boolean isPlatform() {
	var isPlatform = isTag("public_transport", "platform") || isRailwayPlatform();
	return isPlatform && !isTag("usage", "tourism");
	}
	public boolean isRailwayPlatform() {
	return isTag("railway", "platform");
	}

[miklcct]

I would also like to add railway=platform_edge as well.