stmarcin / GTFS_FullFrequency

to replace original frequency of public transport service by a generic one, which assumes ´full frequency´ (no waiting times at public transort stops)

GTFS Full Frequency

R code to replace original frequency of public transport service in GTFS feed by a generic one, which assumes ´full frequency´ (no waiting times at public transort stops)

This repo consists of two scipts:

• GTFS_FullFrequency which replaces original frequency of service by a user-defined generic one;
• GTFS_EdgeWithTime which creates new txt/shp file with edges (lines between the stops) with travel time.

Updates of this repo can be found at the end of this documents. The repo is prepared within MSCA CAlCULUS project (see Funding Statement).

Table of Contents

script GTFS_FullFrequency
script GTFS_EdgeWithTime
Updates
Funding statement

GTFS_FullFrequency

Introduction

The script is intent to replace original frequency of public transport service by a generic one (user-defined maximum waiting times at public transort stops), keeping the original travel times between stops. It is prepared in order to investige impact of public transport´s routing scheme on accessibility level (regardless applied resources, i.e. real frequency).

Required GTFS files

a) files to be simplified: - trips.txt - stop_times.txt b) files to be just copied to the final directory: - agency.txt - routes.txt - stops.txt c) generic files to be created for ´full frequency scenario´: - calendar.txt - frequencies.txt

Source https://developers.google.com/transit/gtfs/reference/

Workflow

1. load libraries

2. simplify trips and stop_times: only one trip per route is selected, The rest are removed.

3. recalculate arrival and departure times to start each trip at 00:00:00

4. create calendar and frequencies files

5. create a destination sub-directory for the output

6. clean the RStudio environment

Detailed description

Required libraries:

library(data.table)
library(chron)
library(lubridate)

Input to be specified:

• dir_GTFS: directory where original GTFS files are stored.
• dir_final: directory where modified GTFS files will be saved.
• headway: generic frequency of service; default: 60 seconds
• GenericDate: generic date of the service (only one day); default: "20180515".
• Threshold: the time converage of a generic GTFS full frequency scenario. Depends on the size of the area or applied threshold for OD matrix (maximum considered travel time); default: 120.

Output

• set of generic GTFS files.

Function syntax:

FullFrequency_GTFS(dir_GTFS, dir_final, headway = 60, GenericDate =  "20180515", Threshold = 120)

Applicaiton

The script was tested on GTFS Madrid´s data (source: http://data-crtm.opendata.arcgis.com).

GTFS_frequencies_apply.R was used to move through all folders (each folder contains GTFS data for one transport mode)

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GTFS_EdgeWithTime

Introduction

This script presents a function which uses orginal GFTS datasets to extracts edges between stops adding to them variable that contains travel time (minimum taken from origin stop_times.txt file). The output may be saved as edges.txt, edges.shp or both. edges.shp may be then used in ArcGIS network data set in order to built simplified public transport model which ingnores waiting times (frequency or exact arrival / departure times) using a simplified travel speeds (no congestion as the minimum travel time is used), i.e. the intermediate model between intermediate PT and advanced PT models defined by Salonen & Toivonen, 2013.

There are two versions of the script:

• GTFS_EdgeWithTime_AllDay.R - the one which automatically generate trips for the whole day (24 hours). Due to further limitations it is not recommended (eg. in ArcGIS Network dataset it built too large database).
• GTFS_EdgeWithTime_SelHH.R - the one which enable for user-defined time range (start and end hours)

Required GTFS files

• stop_times.txt
• stops.txt

Workflow

1. load libraries

2. creare edges:

   • data.table with ids of arrival and departure stops;

   • calculate travel time between stops (minimum).

3. add stop coordinates: each row contains XY of orgin and destinatino node and travel time between them;

   • (optional) save output as edges.txt;

4. (optional) create spatial representation and save output as edges.shp.

Detailed description

Required libraries:

library(data.table)
library(chron)
library(lubridate)
library(sp)
library(sf)

Parameters to be specified:

• dir_GTFS: directory where original GTFS files are stored.
• dir_final: directory where modified GTFS files will be saved.
• ouput: user defined outut: - txt - edges.txt file - shp - edges.shp set of files - all - both, edges.txt and edges.shp set of files.

Additionally version with limited time-range has two more parameters:

• HHstart: numeric; user defined starting hour (default: HHstart = 06)
• HHend: numeric; user defined end hour (default: HHend = 14)

Output

• edges.txt, edges.shp or both (defined by user)

Function syntax - version for the whole day:

GTFS_EdgeWithTime <- function(dir_GTFS, dir_final, ouput = "shp")

Function syntach - version with limited time-range:

GTFS_EdgeWithTime_SelHH <- function(dir_GTFS, dir_final, HHstart = 06, HHend=14, output = "shp")

Applicaiton

The script was tested on GTFS Madrid´s data (source: http://data-crtm.opendata.arcgis.com).

GTFS_EdgeWithTime_SelHH_apply.R and GTFS_EdgeWithTime_AllDay_apply.R were used to move through all folders (each folder contains GTFS data for one transport mode).

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Updates

2018-08-09: solved problem with arrival / departure times coded as "24:MM:SS" (HH >= 24).

2018-09-16: new script added (GTFS_EdgeWithTime.R) & update of README file.

2018-09-26: new scripts were added (GTFS_EdgeWithTime_SelHH and GTFS_EdgeWithTime_AllDay.R - the latter is to replace GTFS_EdgeWithTime.R).

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Licence

License for files: CC-BY-4.0

Funding statement

This document is created within the MSCA CAlCULUS project.

This project has received funding from the European Union's Horizon 2020 research and innovation Programme under the Marie Sklodowska-Curie Grant Agreement no. 749761.
The views and opinions expressed herein do not necessarily reflect those of the European Commission.

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