GTFS Data Dissemination

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Revision as of 16:43, 18 January 2016 by Aaronantrim (talk | contribs) (added section: engagement with 3rd party developers)
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After agencies determine how they plan to create and maintain their data, they must select a process for GTFS dissemination.

Dissemination Methods for Public GTFS Datasets

After the transit agency has created the GTFS zip file and decided whether or not to include data use guidelines, it can be shared with application developers so that applications (e.g., Google Transit) can use the data.

Agency Website

Many agencies maintain a Developer Resources site or page with information, licenses, and links to various open datasets.

These are examples:

The Caltrain developer page provides a summary of recent changes to the GTFS dataset.

Screen capture of http://www.caltrain.com/developer.html taken December 7, 2015

Global Directories

GTFS data is typically made publicly available by sharing the data at a publicized URL. Developers and consuming applications can download GTFS data from the specified URL.

Three websites currently serve as the primary global directories of publicly accessible data:

Transit agencies with GTFS data should consider making this data public to best leverage their investment and maximize the availability of applications based on their GTFS data[1]. The data can be made available on the websites listed above, as well as at the individual agency websites. Trinity Transit[2] is an example of a small agency that has chosen to make GTFS publicly available through its website, as has HART[3] and Pinellas Suncoast Transit Authority (PSTA) in the St. Petersburg/Clearwater area of Florida[4].

Regional Directories

Another example of GTFS data publishing is a regional approach where all GTFS data feeds for a number of nearby agencies are listed on a single centralized site so they are easily discoverable by application developers. The following agencies publish a list of all the publicly available GTFS data for all agencies in the respective state:

  • Oregon Department of Transportation Public Transit Division[5]
  • New York State Department of Transportation[6]
  • Massachusetts Department of Transportation [7]
  • trafiklab.se (Country of Sweden)

Sweden has released GTFS data for 58 public transportation services in the country in August 2012[8]. Elias Arnestrad with Samtrafiken discussed Sweden’s approach toward open public transport data. The data is released through an organization called Samtrafiken[9], which is an organization jointly-owned by about 30 public and private transportation providers. Samtrafiken consolidates open data, and provides technical consulting services and guidance to transport providers. Open data was released following a partnership with Google that began in 2011. This occurred as a result of a legislative mandate, concurrently with a “mind shift in the public transport industry about how [to] define [its] core business.” In addition to GTFS data, Samtrafiken provides several APIs for transit data at www.trafiklab.se. Trafiklab.se includes a blog with news, and a forum for people to propose projects and find collaborators. Elias states the reason this is done through Samtrafiken “is to share the costs for developing those services.”

Engagement with 3rd party developers

Licensing

Many transit agencies release GTFS or other datasets under the terms of a license, which defines how data may be utilized or displayed. Some agencies choose not to invoke the formalities of a license, and instead provide guidelines (e.g. Anaheim Resort Transportation).

Releasing data under an overly restrictive license, or terms that are inconsistent with industry practice can make it more difficult for 3rd party developers to utilize transit data, and reduce the variety of applications that utilize a dataset. Mapzen's Transitland project has drafted a model license (MS Word document) "that transit agencies can attach to their GTFS feeds, their real-time feeds, and any other data that they'd like to share with outside consumers. This model license allows the freedoms that developers want, while also including all the protections that agencies need."[10]

Soliciting feedback

Many agencies include a contact for developers on the agency website. Some agencies provide contact information in optional feed_contact_email and feed_contact_url fields, proposed for inclusion in the Spec.

Resolving data quality issues

Data is rarely perfect, and most 3rd party applications take some role in monitoring data quality. To facilitate continuous improvement and demonstrate commitment to quality data, some transit agencies publish a list of known issues. Below is screenshot of one such page from soundtransit.org.

Screenshot of OTD Data Quality page from Sound Transit.

Demonstrating Applied Uses of GTFS Data

With the GTFS readily available, mobile app developers may create different applications for riders. When applications are created by third-party developers using a transit agency’s GTFS data, the agency may choose to make transit riders aware of these applications. One method of increasing awareness is to showcase certain applications on the agency’s website.

TriMet[11], BART in San Francisco[12], Metropolitan Transportation Authority (MTA) in New York[13], Chicago Transit Authority[14], GoTriangle in North Carolina[15], HART in Tampa, FL[16], MBTA in Massachusetts[17], KCATA in Kansas City [18], and Utah Transit Authority[19] are all examples of medium to large transit agencies that publishes information about 3rd party applications in “App Center” websites. Mendocino Transit Authority is an example of a small transit agency that provides an “App Center”[20]. City-Go-Round[21] is a global directory of third-party transit applications.

If an agency produces such a showecase, these showcased applications should be selected by the agency based on clear, defined criteria. McHugh from TriMet explains their methodology for showcasing applications. “Our philosophy has always been not to police applications. We have two criteria [we examine for before] posting: (1) The App must work as it says it does, and (2) the App must use our developer resources/data. This is to discourage screen scraping [and encourage use of the official GTFS dataset]”[22].

Wong et al. also encourage an active relationship with the third-party software developer community when openly sharing GTFS data[23].

  1. ↑ The Many Uses of GTFS Data
  2. ↑ Trinity Transit. "Google Maps and Mobile Applications."
  3. ↑ Hillsborough Area Regional Transit. "Build your own HART apps."
  4. ↑ Pinellas Suncoast Transit Authority. "PSTA Developer Resources."
  5. ↑ Oregon Department of Transportation Public Transit Division. "GTFS Data Download Links."
  6. ↑ New York State Department of Transportation
  7. ↑ Massachusetts Department of Transportation. "MassDOT Developers Page."
  8. ↑ https://groups.google.com/d/topic/googletransitdatafeed/pl_ByBZhJcE/discussion
  9. ↑ www.samtrafiken.se
  10. ↑ https://transit.land/an-open-project/ Accessed 18 January 2016
  11. ↑ TriMet. "TriMet App Center."
  12. ↑ San Fransisco Bay Area Rabid Transit District. "Third Party Apps."
  13. ↑ Metropolitan Transportation Authority. "App Center."
  14. ↑ Chicago Transit Authority. "App Center."/
  15. ↑ GoTriangle. "App Center."
  16. ↑ Hillsborough Area Regional Transit. "App Center."
  17. ↑ Massaschusetts Bay Transportation Authority. "App Center."
  18. ↑ Kansas City Area Transportation Authority. "App Center."
  19. ↑ Utah Transit Authority. "App Center."
  20. ↑ Mendocino Transit Authority. "App Center."
  21. ↑ Front Seat Management, LLC. "City-Go-Round."
  22. ↑ Bibiana McHugh, "Leveraging GTFS paper," ed, 2012.
  23. ↑ James Wong, Landon Reed, Kari Watkins, and Regan Hammond (2013), "Open Transit Data: State of the Practice and Experiences from Participating Agencies in the United States," in Transportation ResearchBoard 92nd Annual Meeting, Washington, D.C., USA, p. 15, January 13-17, 2013.
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