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Calculate relative times from a specified point by multi-modal transport versus private automobile, along with (optionally) corresponding walking distances.

Source: R/times-multi-modal.R
m4ra_times_mm_car.Rd

This city expects weighted networks to have been generated with the m4ra_batch_weight_networks function, and for corresponding networks to exist in the m4ra cache directory for the specified city.

Usage

m4ra_times_mm_car(
  net_sc = NULL,
  gtfs = NULL,
  city_name = NULL,
  day = NULL,
  start_time_limits = NULL,
  initial_mode = "foot",
  final_mode = "foot",
  from = NULL,
  duration_max = NULL,
  fast = FALSE,
  n_closest = 10L,
  walk_dists = TRUE,
  quiet = FALSE
)

Arguments

net_sc

Local file path to a silicate, "SC", format object containing network data used to generate weighted street networks.

gtfs

Local file path to a gtfsrouter object saved via saveRDS, containing GTFS (General Transit Feed Specification) data for network represented in net_sc. This .Rds object may include additional timetable or transfer information in addition to data represented in original zip-format data of provided GTFS feed.

city_name

Name of city used to name cached files.

day

As for the 'gtfs_traveltimes' function of gtfsrouter, the day for which the matrix is to be calculated.

start_time_limits

As for the 'gtfs_traveltimes' function of gtfsrouter, a vector of two values specifying the earliest and latest departure times from each station.

initial_mode

Initial mode of transport from origin points towards public transport stop.

final_mode

The mode of transport used for the final stage from GTFS stops to destination points.

from

Vector of OSM ID values of vertices from which ratios are to be calculated. Typically obtained by loading one weighted network, and sampling or extracting vertices from the function m4ra_vertices.

duration_max

If specified, only calculate times from each point to the nearest GTFS stops out to specified maximal duration in seconds. Values may be provided if overall travel times are only of interest out to some defined range or maximal value. Specifying values for this parameter can can considerably reduce calculation times.

fast

Values of TRUE generate potentially enormous matrices which may not fit in local memory. The default value of FALSE is generally safer, but calculation may take considerably longer.

n_closest

Final travel times to each destination point are calculated by tracing back times to this number of closest GTFS stops. Lower values will result in faster calculation times, yet with potentially inaccurate results.

walk_dists

If TRUE, also calculate equivalent walking distances.

quiet

If FALSE, display progress information on screen.

Value

A data.frame of destination vertices, including Open Street Map ID values, and longitude and latitude values, and four variables:

  • 'car_t' Times in seconds to travel with automobile.

  • 'mm_t' Times in seconds for equivalent multi-modal transport.

  • 'walk_d' Equivalent walking distance in kilometres.

  • 'ratio' Ratio of multi-modal to automobile travel times.

See also

Other analyses: m4ra_bike_car_ratio_areas(), m4ra_times_bike_car()

Examples

if (FALSE) { # \dontrun{
city <- "<city_name>"
net <- m4ra_load_cached_network (city = city, mode = "foot")
v <- m4ra_vertices (net, "<city_name>")
from <- sample (v$id, size = 10)
dat <- m4ra_mm_car_ratios (city = city, from = from)
} # }