This function converts a public transport data set in GTFS format into a
GPS-like table with the space-time positions and speeds of public transport
vehicles. The function also allow users to set the spatial resolution of the
output and to adjust the speed of public transport vehicles given a
min_speed and max_speed range.
transport_model(
gtfs_data,
min_speed = 2,
max_speed = 80,
new_speed = NULL,
parallel = TRUE,
ncores = NULL,
spatial_resolution = 100,
output_path = NULL,
continue = FALSE
)A path to a GTFS file or a GTFS data organized as a list of
data.tables created with gtfstools::read_gtfs().
numeric (in km/h) or a speed units value. Minimum speed to
be considered as valid. Values below minimum speed will be updated
according to the new_speed parameter, which can affect the arrival
and departure times of vehicles at transit stops. Defaults to 2
km/h.
numeric (in km/h) or a speed units value. Maximum speed to
be considered as valid. Values above maximum speed will be updated
according to the new_speed parameter, which can affect the arrival
and departure times of vehicles at transit stops. Defaults to 80
km/h.
numeric (in km/h) or a speed units value. Speed value used
to replace the speeds that fall outside the min_speed and max_speed
range or which are missing from the GTFS input. When new_speed = NULL
(the default), the function uses the average speed of the entire GTFS
data feed.
logical. Decides whether the function should run in parallel.
Defaults is TRUE.
integer. Number of cores to be used in parallel execution. This
argument is ignored if parallel is FALSE. Default (NULL) selects
the total number of available cores minus one.
The spatial resolution in meters. Defaults to 100.
The function only creates points in order to guarantee that the
minimum distance between two consecutive points will be at most the
spatial_resolution value. If a given GTFS shape_id has two
consecutive points with a distance smaller than the spatial resolution,
the algorithm will not remove such points.
character. A directory path. If NULL (Default), the
function returns the output. If the user passes a valid passed, the
output will be saved in the output_path dir. Note that that the
output of each public transport shape_id is saved separately in
different files. Setting an output_path is recommended when working
with large public transport system because the output of the function
can be significantly large.
logical. Argument that can be used only with output_path When TRUE, it skips processing the shape identifiers that were already saved into files. It is useful to continue processing a GTFS file that was stopped for some reason. Default value is FALSE.
A data.table sf_linestring object or NULL.
Other Core function:
emission_model()
# \donttest{
if (requireNamespace("gtfstools", quietly=TRUE)) {
# read GTFS
gtfs_file <- system.file("extdata/bra_cur_gtfs.zip", package = "gtfs2emis")
gtfs <- gtfstools::read_gtfs(gtfs_file)
# keep a single trip_id to speed up this example
gtfs_small <- gtfstools::filter_by_trip_id(gtfs, trip_id ="4451136")
# run transport model
tp_model <- transport_model(gtfs_data = gtfs_small,
min_speed = 2,
max_speed = 80,
new_speed = 20,
spatial_resolution = 100,
parallel = FALSE)
}
#> Converting shapes to sf objects
#> Processing the data
# }