Underground stops connected to ground level street

[hbruch]

Expected behavior

Underground railway stops should be linked to platforms instead of streets at ground level.

Observed behavior

For VVS dataset, some underground rail stops are linked to ground level street.

Version of OTP used (exact commit hash or JAR name)

e151d7f

Data sets in use (links to GTFS and OSM PBF files)

VVS GTFS
RegBez Stuttgart OSM

Steps to reproduce the problem

Route from e.g. (48.71679, 9.11230) to (48.77194, 9.15522)

Thoughts

Currently, stops are snapped to the OSM street network either by TransitToTaggedStopsModule or StreetLinkerModule.

TransitToTaggedStopsModule requires that GTFS stop has a stop_code and OSM stop must exist as node with a matching ref attribute, which usually is the case for bus stops.

StreetLinkerModule on the other hand calls VertexLinker.linkVertexPermanently which does not consider any transit specific information, a TransitStopVertex is linked to it's closest reachable street node.

Solution idea:

A quick and dirty fix would be to filter for platformEdges in VertexLinker.linkToStreetEdges (probably only for Scope.PERMANENT , INITIAL_SEARCH_RADIUS_METERS and TraverseMode.WALK):

	Predicate<StreetEdge> platformEdgesOnlyIfRailStop = e -> true;
    if (vertex instanceof TransitStopVertex) {
      Set<TransitMode> modes = ((TransitStopVertex) vertex).getModes();
      if (modes.contains(TraverseMode.RAIL) || modes.contains(TransitMode.SUBWAY) || modes
              .contains(TransitMode.TRAM)) {
        platformEdgesOnlyIfRailStop = e -> (e.getStreetClass() & StreetEdge.CLASS_TRAIN_PLATFORM) > 0;
      }
    }