gtfstools (version 1.4.0)

get_stop_times_patterns: Get stop times patterns

Description

Identifies spatial and spatiotemporal patterns within the stop_times table. Please see the details to understand what a "pattern" means in each of these cases.

Usage

get_stop_times_patterns(
  gtfs,
  trip_id = NULL,
  type = "spatial",
  sort_sequence = FALSE
)

Value

A data.table associating each trip_id to a pattern_id.

Arguments

gtfs

A GTFS object, as created by read_gtfs().

trip_id

A character vector including the trip_ids to have their stop_times entries analyzed. If NULL (the default), the function analyses the pattern of every trip_id in the GTFS.

type

A string specifying the type of patterns to be analyzed. Either "spatial" (the default) or "spatiotemporal".

sort_sequence

A logical specifying whether to sort timetables by stop_sequence. Defaults to FALSE, otherwise spec-compliant feeds, in which timetables points are already ordered by stop_sequence, would be penalized through longer processing times. Pattern identification based on unordered timetables may result in multiple ids identifying what would be the same pattern, had the table been ordered.

Details

Two trips are assigned to the same spatial pattern_id if they travel along the same sequence of stops. They are assigned to the same spatiotemporal pattern_id, on the other hand, if they travel along the same sequence of stops and they take the same time between stops. Please note that, in such case, only the time between stops is taken into account, and the time that the trip started is ignored (e.g. if two trips depart from stop A and follow the same sequence of stops to arrive at stop B, taking both 1 hour to do so, their spatiotemporal pattern will be considered the same, even if one departed at 6 am and another at 7 am). Please also note that the stop_sequence field is currently ignored - which means that two stops are considered to follow the same sequence if one is listed right below the other on the stop_times table (e.g. if trip X lists stops A followed by stop B with stop_sequences 1 and 2, and trip Y lists stops A followed by stop B with stop_sequences 1 and 3, they are assigned to the same pattern_id).

Examples

# \dontshow{
  old_dt_threads <- data.table::setDTthreads(1)
  on.exit(data.table::setDTthreads(old_dt_threads), add = TRUE)
# }
data_path <- system.file("extdata/ber_gtfs.zip", package = "gtfstools")

gtfs <- read_gtfs(data_path)

patterns <- get_stop_times_patterns(gtfs)
head(patterns)

# use the trip_id argument to control which trips are analyzed
patterns <- get_stop_times_patterns(
  gtfs,
  trip_id = c("143765658", "143765659", "143765660")
)
patterns

# use the type argument to control the type of pattern analyzed
patterns <- get_stop_times_patterns(
  gtfs,
  trip_id = c("143765658", "143765659", "143765660"),
  type = "spatiotemporal"
)
patterns