Specs gtfs2ntfs: reading shapes & frequencies #424

papailio · 2019-10-18T12:15:39Z

No description provided.

woshilapin · 2019-10-18T12:34:17Z

src/documentation/gtfs_to_ntfs_specs.md

+A new trip is created, departing from the first stop every `headway_secs` seconds within the time period between `start_time` and `end_time`. Stop times of the referenced trip are used to calculate the time interval between two stop departures.
+The departure time at the first stop of the last trip should not be later than the `end_time` value.
+
+Th identifier for each new trip is generated using the following pattern: \<trip_id>:<auto-incrimented integer\> and maintains the rest of the attributes of the sample trip. That is, all new trips are assigned to the same route as the route of the sample trip, have the same service_id, etc. 


Suggested change

Th identifier for each new trip is generated using the following pattern: \<trip_id>:<auto-incrimented integer\> and maintains the rest of the attributes of the sample trip. That is, all new trips are assigned to the same route as the route of the sample trip, have the same service_id, etc.

The identifier for each new trip is generated using the following pattern: \<trip_id>:<auto-incremented integer\> and maintains the rest of the attributes of the sample trip. That is, all new trips are assigned to the same route as the route of the sample trip, have the same service_id, etc.

woshilapin · 2019-10-18T12:35:16Z

src/documentation/gtfs_to_ntfs_specs.md

+A new trip is created, departing from the first stop every `headway_secs` seconds within the time period between `start_time` and `end_time`. Stop times of the referenced trip are used to calculate the time interval between two stop departures.
+The departure time at the first stop of the last trip should not be later than the `end_time` value.
+
+Th identifier for each new trip is generated using the following pattern: \<trip_id>:<auto-incrimented integer\> and maintains the rest of the attributes of the sample trip. That is, all new trips are assigned to the same route as the route of the sample trip, have the same service_id, etc. 


If I remember correctly, the frequencies are using a virtual trip that need to be destroyed once all frequencies have been transformed into stop_times. Maybe this can be mentioned in the specification too?

woshilapin · 2019-10-18T12:42:22Z

src/documentation/gtfs_to_ntfs_specs.md

+| geometries.txt | geometry__id | ID | shapes.txt | shape_id | All slashes `/` are removed |
+| geometries.txt | geometry__wkt | Required | shapes.txt | shape_pt_lat, shape_pt_lon, shape_pt_sequence | A WKT LINESTRING geometry is created from the 3 input fields. |
+
+### Reading frequencies.txt


When I did the documentation, I had these 3 special cases:

src/gtfs/read.rs:954 WARN/IGNORE [frequency for trip <frequency.trip_id> has same start and end time] if the frequency start time and end time are the same

src/gtfs/read.rs:964 WARN/IGNORE [frequency mapped to an unexisting trip <frequency.trip_id>] if the frequency refers to a vehicle_journey which doesn't exist

src/gtfs/read.rs:975 WARN/IGNORE [frequency mapped to trip <frequency.trip_id> with no stop_times] if the vehicle_journey relative to the frequency doesn't have any stop_time

They are very technical but I think they should be documented one way or another (except maybe the second one which might be evident enough).

datanel · 2019-10-19T08:36:35Z

src/documentation/gtfs_to_ntfs_specs.md

+Frequencies are transformed into explicit passing times by creating new trips that operate on regular times within the specified period. For each line of the GTFS frequencies.txt file, the referenced trip and its stop_times are used as a sample to create the new trips whose stop_times are calculated based on the given headway.
+
+A new trip is created, departing from the first stop every `headway_secs` seconds within the time period between `start_time` and `end_time`. Stop times of the referenced trip are used to calculate the time interval between two stop departures.
+The departure time at the first stop of the last trip should not be later than the `end_time` value. In case both values for `start_time` and `end_time` are equal, the frequency is ignored (no new trip is created).


equals? (not sure)

What about adding the ignored case when endtime is inferior to the starttime ?

ArnaudOggy · 2019-10-23T08:44:53Z

src/documentation/gtfs_to_ntfs_specs.md

@@ -187,7 +189,7 @@ immediately with an error.
 | trips.txt | route_id | Required | trips.txt | route_id | cf. NTFS `route_id` definition above to specify the proper reference. |
 | trips.txt | service_id | Required | trips.txt | service_id |  |
 | trips.txt | trip_id | Required | trips.txt | trip_id |  |
-| trips.txt | trip_headsign | Optional | trips.txt |  | `trip_short_name`, of if empty `trip_headsign` |
+| trips.txt | trip_headsign | Optional | trips.txt |  | `trip_short_name`, or if empty `trip_headsign` |


Since NTFS 0.10 there are now 2 fields "trip_headsign" and "trip_short_name".
It's not yet implemented in TransitModel, but I think it will be soon.

I'm ok to do this later to avoid opening toi many subjects at once

ArnaudOggy · 2019-10-23T08:50:21Z

src/documentation/gtfs_to_ntfs_specs.md

+
+| NTFS file | NTFS field | Constraint | GTFS file | GTFS field | Note |
+| --- | --- | --- | --- | --- | --- |
+| geometries.txt | geometry__id | ID | shapes.txt | shape_id | All slashes `/` are removed |


geometry_id and geometry_wkt (remove one underscore)

prhod · 2019-10-23T10:03:33Z

src/documentation/gtfs_to_ntfs_specs.md

+Frequencies are transformed into explicit passing times by creating new trips that operate on regular times within the specified period. For each line of the GTFS frequencies.txt file, the referenced trip and its stop_times are used as a sample to create the new trips whose stop_times are calculated based on the given headway.
+
+A new trip is created, departing from the first stop every `headway_secs` seconds within the time period between `start_time` and `end_time`. Stop times of the referenced trip are used to calculate the time interval between two stop departures.
+The departure time at the first stop of the last trip should not be later than the `end_time` value. In case both values for `start_time` and `end_time` are equal, the frequency is ignored (no new trip is created).


What about adding the ignored case when endtime is inferior to the starttime ?

prhod · 2019-10-23T10:09:13Z

src/documentation/gtfs_to_ntfs_specs.md

+A new trip is created, departing from the first stop every `headway_secs` seconds within the time period between `start_time` and `end_time`. Stop times of the referenced trip are used to calculate the time interval between two stop departures.
+The departure time at the first stop of the last trip should not be later than the `end_time` value. In case both values for `start_time` and `end_time` are equal, the frequency is ignored (no new trip is created).
+
+Note that the referenced trip (and its stop_times) is only used as a sample and is not generated by the reader in the end. In case the referenced trip ans/or its associated stop_times do not exist, the frequency is ignored (no new trip is created).


I'm not convinced by the use of generated by the reader. What about something like and is deleted is the resulting data ?

Typo in ans/or

Specs gtfs2ntfs: reading shapes & frequencies

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woshilapin reviewed Oct 18, 2019

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Specgtfs2ntfs: precisions after review

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datanel reviewed Oct 19, 2019

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woshilapin previously approved these changes Oct 22, 2019

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ArnaudOggy reviewed Oct 23, 2019

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Specs gtfs2ntfs: fix typos and formatting

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papailio dismissed woshilapin’s stale review via 863f346 October 23, 2019 09:38

ArnaudOggy previously approved these changes Oct 23, 2019

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Specs gtfs2ntfs: corrections after review

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papailio dismissed ArnaudOggy’s stale review via 5b95041 October 23, 2019 10:39

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ArnaudOggy merged commit b78e05a into hove-io:master Oct 23, 2019

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Specs gtfs2ntfs: reading shapes & frequencies #424

Specs gtfs2ntfs: reading shapes & frequencies #424

papailio commented Oct 18, 2019

woshilapin Oct 18, 2019

woshilapin Oct 18, 2019

woshilapin Oct 18, 2019

datanel Oct 19, 2019

prhod Oct 23, 2019

ArnaudOggy Oct 23, 2019 •

edited

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prhod Oct 23, 2019

ArnaudOggy Oct 23, 2019

prhod Oct 23, 2019

prhod Oct 23, 2019

	Th identifier for each new trip is generated using the following pattern: \<trip_id>:<auto-incrimented integer\> and maintains the rest of the attributes of the sample trip. That is, all new trips are assigned to the same route as the route of the sample trip, have the same service_id, etc.
	The identifier for each new trip is generated using the following pattern: \<trip_id>:<auto-incremented integer\> and maintains the rest of the attributes of the sample trip. That is, all new trips are assigned to the same route as the route of the sample trip, have the same service_id, etc.

Specs gtfs2ntfs: reading shapes & frequencies #424

Specs gtfs2ntfs: reading shapes & frequencies #424

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papailio commented Oct 18, 2019

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ArnaudOggy Oct 23, 2019 • edited Loading

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ArnaudOggy Oct 23, 2019 •

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