grtur

grtur is a proposed open-data format and protocol intended for the exchange of public transportation and routing information. It seeks to provide a modular, interoperable schema that can describe stops, routes, schedules, live vehicle positions, and related events. The term grtur is an acronym for Geospatial Routing and Transport Unified Resources. It is designed to supplement existing standards by offering a flexible extension mechanism for new transportation modes and localized data needs.

The concept emerged in discussions among researchers and city planners in the 2010s as a means to improve interoperability between transit agencies and routing applications. A community-led draft specification circulated in public repositories, with several independent implementations and pilot projects in municipal settings. The project has since produced several versions, with attention to backward compatibility and schema validation.

grtur uses a JSON-based core with optional YAML representations. The core model covers entities such as stops, stop times, routes, trips, service calendars, and vehicle positions. Extensions allow for real-time feed integration, fare rules, accessibility attributes, and geospatial metadata. Data validation relies on a formal schema, enabling testing and offline processing.

Grtur remains a niche format, with limited institutional adoption compared to established standards in transit data exchange. Advocates cite improved extensibility and cross-modal routing, while critics note fragmentation and limited tooling. It is commonly studied in academic settings and pilot programs. Related standards include GTFS (General Transit Feed Specification), open data standards, and public transportation data.