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Scaffold a Standard-Compliant GTFS Feed from Observed Stop Events

Source: R/assemble.R
rt2s_scaffold.Rd

Baseline-free assembly: synthesizes every spec-required GTFS file from observed stop events plus user-supplied agency metadata, with deterministic, properly linked identifiers. Call it directly when there is no planned feed to inherit from at all; rt2s_assemble also falls back to it when it is given no baseline.

Usage

rt2s_scaffold(
  events,
  agency = NULL,
  stops = NULL,
  route_type = 3L,
  shapes = NULL,
  tz = NULL,
  feed_lang = "en",
  feed_contact_email = NULL,
  feed_contact_url = NULL,
  strict = FALSE
)

Arguments

events

Observed stop events (see observed-stop-events).

agency

Named list with name, url, timezone. Placeholders + a warning when omitted.

stops

Optional table of stop locations: stop_id plus latitude/longitude (or stop_lat/stop_lon), optionally stop_name. Stops present in events but absent here get NA coordinates and a warning (the result will not validate until they are filled).

route_type

GTFS route type for scaffolded routes. Default 3 (bus).

shapes

Optional shapes.txt-shaped table (e.g. from gps2gtfs::g2g_shapes_from_trips()). Linked to trips via trips.shape_id when the events carry a matching shape_ref (see rt2s_events_from_stop_times(shape_ref_prefix=)); shapes not referenced by any trip are dropped, and references without matching geometry warn (or error under strict).

tz

Timezone of the service days; used to derive GTFS clock strings (with >24:00:00) from absolute event times. Defaults to agency$timezone, else "UTC".

feed_lang

Primary language of the feed, written to feed_info.feed_lang (spec-required in feed_info.txt). Default "en".

feed_contact_email, feed_contact_url

Optional recommended feed_info.txt contact fields. Written only when supplied.

strict

Logical. When TRUE, conditions that would yield a non-publishable feed - placeholder agency metadata or stops missing spec-required coordinates - raise an error instead of a warning. Use it as a publish gate: a scaffold that returns under strict = TRUE has no known spec-required gaps introduced by scaffolding (it is not a substitute for full GTFS validation). Default FALSE.

Value

A gtfsio-convention feed object (class gtfs, named list of data.tables) - write it with gtfsio::export_gtfs().

Details

What cannot come from GTFS-RT and must be supplied (or is filled with a flagged placeholder): agency name/url/timezone (spec-required), stop coordinates (stops argument, e.g. from gps2gtfs::g2g_stops_from_positions()), and route_type (defaults to 3, bus, with a warning).