Calculate transfers.txt to improve routing about osm2gtfs HOT 9 OPEN

Maybe we should start with a simple offline implementation of this and then later maybe introduce different TransfersCreators.

from osm2gtfs.

For information, this self made Rust lib is available : https://github.com/CanalTP/transfe_rs/

from osm2gtfs.

Apparently, Navitia's routing algorithm can produce really bad results when transfers.txt file is missing.

So computing one automatically should be a priority I think.

from osm2gtfs.

We should analyze in which way the transfer.txt is related with OSM in order to find a solution for this issue.

Maybe this is one way: take OSM stops related in a Stop Area (not in a station) and fill transfers.txt with the data from stops, and columns transfer_type=2 and min_transfer_time = the frequency of the line.

Example:

Assuming Stop Area X

• stop A (also member of route 1)
• stop B (also member of route 2 and route 3)
• stop C (also member of route 4)

transfers.txt

from_stop_id, to_stop_id, transfer_type
A, B, 2, frequency of route 2
A, B, 2, frequency of route 3
A, C, 2, frequency of route 4
B, A, 2, frequency of route 1
B, B, 2, frequency of route 2
B, B, 2, frequency of route 3
B, C, 2, frequency of route 4
C, A, 2, frequency of route 1
C, B, 2, frequency of route 2
C, B, 2, frequency of route 3

from osm2gtfs.

The GTFS transfer information is a walking time between 2 stop points. I don't understand your proposal of using the frequency of the route.
Personnaly, I would use a walking path using OSM ways with a specific walking speed to compute de duration of the transfer. Thou I don't know yet how I would to this ...
As a first step, using a Manhattan distance could be an approximation.
What do you think of that ?

from osm2gtfs.

Another option is to test the routes against an instance of OSRM using a walking algorithm, that should give you the shortest legal walking distance and time between any two points. If highway crossings are necessary, Manhattan distances can be wrong.

from osm2gtfs.

OSRM is a good idea ! do you know a free of use instance available ?
You're right about highway, the same issue can happen with river. But on the other hand, there is no need for a third part service to generate the GTFS...

from osm2gtfs.

I have my own instance of OSRM, its not complicated to set up, so running a private instance is absolutely an option. I havn't tried with a world wide map, downloading and loading Brazil takes about 1.5 hours on my personal lap top, I guess a server would be a little bit quicker.

from osm2gtfs.

The GTFS transfer information is a walking time between 2 stop points. I don't understand your proposal of using the frequency of the route.

I was thinking on the transfers.txt mainly as a way to specify a tansfer between routes, in fact is the way it works if we set transfer_type = 0. When setting transfer_type = 2 it makes total sense to use walking time in min_transfer_time, as you say.

My proposal was wrong but just to explain my self: The use of frequency of the route as min_transfer_time was considered as "kind of" the distance (in time) between one itinerary and the next, so I was thinking on the time the user will "had" for moving from one stop to the other (not the time needed).

from osm2gtfs.