https://github.com/transitapp/gtfsnodelib
A Node.js librairie for GTFS
https://github.com/transitapp/gtfsnodelib
Last synced: 4 months ago
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A Node.js librairie for GTFS
- Host: GitHub
- URL: https://github.com/transitapp/gtfsnodelib
- Owner: TransitApp
- License: mit
- Created: 2017-12-29T16:27:43.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2023-04-20T02:19:34.000Z (about 3 years ago)
- Last Synced: 2025-07-18T14:05:35.853Z (11 months ago)
- Language: JavaScript
- Size: 354 KB
- Stars: 17
- Watchers: 15
- Forks: 6
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Node.js light GTFS loading and manipulation
A Node.js naive library to load and manipulate GTFS datasets.
## Installation
```npm install --save @transit/gtfs```
## Usage
The tables of the GTFS will be loaded only when accessed, and not upfront. This allows manipulation of the small tables
(like routes.txt or stops.txt) without having to load the big tables (like stop_times.txt).
## Example
If you want to remove all the stops called 'Central Station' and the stop_times using this stop:
```js
const { Gtfs } = require('@transit/gtfs');
const gtfs = new Gtfs('pathToTheFolderContainingTheGtfs');
gtfs.forEachStop((stop) => {
if (stop.stop_name === 'Central Station') {
gtfs.removeStop(stop);
}
});
gtfs.forEachStopTime((stopTime) => {
if (!gtfs.getStopOfStopTime(stopTime)) {
gtfs.removeStopTime(stopTime);
}
});
// Let's also clean up the frequencies, to keep a consistent GTFS.
gtfs.forEachFrequency((frequency) => {
const fromStop = gtfs.getStopWithId(frequency.from_stop_id);
const toStop = gtfs.getStopWithId(frequency.to_stop_id);
if (!fromStop || !toStop) {
gtfs.removeFrequency(frequency);
}
});
gtfs.exportAtPath('somePathWhereYouWantToExportTheGtfs', (error) => {
if (error) { throw error };
// Done
});
```
### Indexes
The tables are loaded and saved as Maps, to allow o(1) access using the ids. The routes are therefore indexed by the
`route_id` value, which is therefore saved in `route.route_id` but also as an index.
**This indexing is not automatically kept up to date.**
If you change the `route_id` just by changing the internal value of the `route` the index **won't** be updated, and
therefore the table will be corrupted. To properly update the id of a route, you should replace it:
```js
const route = gtfs.getRouteWithId('oldId');
gtfs.removeRoute(route);
route.route_id = 'newId';
gtfs.addRoute(route);
```
### Synchronous loading
The goal of this implementation was to avoid loading upfront all the tables. Therefore, they are loaded only when
required. This makes the code faster to run (if some tables are not required at all).
The drawback, is that any function could trigger the loading of a table. Since we do not want to turn every function into an async one, the loading of the tables is done synchronously.
## Naming
The wording used in the official GTFS specification has been followed as much as possible, including the inconsistencies.
For example, the table containing the stops is "stops", but the table containing the agencies is "agency". The reason
for this being that, in the specification, the files are named `stops.txt` vs `agency.txt`.
Most of the time, the name of one item of a table is the singular of the table name (routes -> route, stops -> stop),
but for the `shapes.txt`, since one item of the table is not a "shape" per-se, but just a point, the name used is
"shapePoint" (consistent with the name `shape_pt_sequence`, `shape_pt_lat` and `shape_pt_lon` of the spec).
## Support and contact
Please post any issues you find on [the repo of the project](https://github.com/TransitApp/gtfsNodeLib/issues). And
do not hesitate to contact [Transit App](https://github.com/TransitApp) directly if you have any questions.