transitland-route-geometry-generator

README

Transitland route geometry generator

Generate your transitland route shapes from gtfs trips

This project aims to generate transitland gtfs routes shapes from gtfs trips shapes.

Installation

Go binary

go install github.com/phoops/transitland-route-geometry-generator/...@latest

Github release - recommended

You can grab the latest release on this repository releases

Docker image

phoops/transitland-route-geometry-generator

docker run run --rm -ti phoops/transitland-route-geometry-generator 1 -d postgres://transit:transit@db/gtfsdb?sslmode=disable

How it works?

On gtfs spec, we don't have a direct association between shapes and routes, in transitland domain is possibile to associate a geometry to a route.

In order to associate a geometry to a transitland route, we need to process the route trips and the shapes associated to the trips.

In order to keep thing simple, we choose the longest geometry of all the trips and promote that geometry to the geometry of the route.

This project depends on postgresql and postgis and we interact directly with the transitland database, so transitland schema is needed.

Steps

• Fetch trips for a specific gtfs feed and routes (Both can be provided as input to the CLI)
• Choose the longest shape associated to the trips of the routes
• Take the geometry of chosen shape and promote that to route geometry
• Persit the geometry in `tl_route_geometries table

The shapes generation is idempotent, so you can use the CLI freely in your workflow, without worring of breaking things, when the shapes geometry are updated by a new feed, they will be imported and the route shape is computed again

Usage

    Generate geometries for your gtfs routes in transistland.
    Uses your trips geometries in order to compute the route shape
    More information at https://github.com/phoops/transitland-route-geometry-generator

    Usage:
    transitland-route-geometry-generator [command]

    Available Commands:
    completion  generate the autocompletion script for the specified shell
    generate    Generate routes
    help        Help about any command
    version     Print the version

    Flags:
    -h, --help      help for transitland-route-geometry-generator
    -v, --verbose   verbose output

Generate routes

Usage:
  transitland-route-geometry-generator generate [flags]

Flags:
  -d, --database string   postgres database connection string
  -n, --dry-run           dry run generation, without inserts
  -h, --help              help for generate
  -r, --routes ints       route ids to include in generation, all by default

The -v flag will output more informations about the process, also the raw postgresql queries made by the cli.

The generate command wants a single argument, representing the id of the gtfs feed, this id can be obtained querying transitland, or in the database table current_feeds.

The -d flag is also required, you should specify a postgresql connection string, like postgres://transit:transit@db/gtfsdb?sslmode=disable.

The -r flag will restrict the route shapes generation only to specific route ids, routes should be separated by comma, ex: -d 1,2,3,4.

tl;dr:

transitland-route-geometry-generator generate 1 -d "postgres://transit:transit@localhost/gtfsdb?sslmode=disable"

Dry run

If you want to only get the computed shapes for your routes, you can use the -n flag, this will skip the database write of route shapes. The output will be a table like that

{"level":"info","ts":"2021-11-30T12:56:58.274+0100","caller":"commands/generator.go:50","msg":"starting generation","command":"generate","verbose":false,"dry-run":true,"feed_version_id":1}
+----------+--------------+------------------+
| ROUTE ID | DIRECTION ID | LONGEST SHAPE ID |
+----------+--------------+------------------+
|        1 |            0 |                4 |
|        1 |            1 |                2 |
|        2 |            0 |                1 |
|        2 |            1 |                8 |
+----------+--------------+------------------+
{"level":"info","ts":"2021-11-30T12:56:58.350+0100","caller":"commands/generator.go:88","msg":"dry run completed, run again without the n flag","command":"generate","verbose":false}

If you pass the -v flag, the output will contain also the raw geometry and the centroid of shape.

tl;dr:

transitland-route-geometry-generator generate 1 -n -d "postgres://transit:transit@localhost/gtfsdb?sslmode=disable"