FAQs on topics related to Location Referencing

TISA provides Frequently Asked Questions (FAQs) and Best Practice information (How-to) for topics related to Location Referencing on digital maps.  These FAQs are incrementally made available as work product of TISA's Location Referencing Work Group.  

Location Referencing

Location referencing is a foundational concept in intelligent transport systems (ITS), enabling the exchange of spatial information—such as traffic events, route segments, or points of interest—between systems that may use different digital maps. To ensure interoperability, location references must be interpretable regardless of the underlying map provider, geometry, or data model.

Two main approaches exist: pre-coded referencing and dynamic referencing.

• Pre-coded location referencing, such as used in RDS-TMC, relies on predefined location tables. Each location is assigned a unique identifier, which is referenced in messages. This method is compact and efficient but limited in flexibility. Only locations present in a pre-agreed table and appropriately tagged in a digital map can be referenced. Updates require coordination between table-owners, map providers, content and service providers, and receiver manufacturers. This makes it not suitable for dynamic or ad-hoc location encoding.
  
  
• Dynamic location referencing, by contrast, allows any location to be encoded on-the-fly using semantic and geometric attributes. This approach is map-agnostic and supports real-time applications such as traffic incident reporting, navigation, and routing. A notable method in this category is OpenLR™ : a widely adopted open-source dynamic location referencing method used extensively across the ITS eco-system.

Location Referencing Methods

The table Overview of Location Referencing Methods provides a (non-exhaustive) overview of the many location referencing methods and variants used in the ITS eco-system.

FAQs on Location Referencing

The page FAQs provides the entry point on the Frequently Asked Questions on Location Referencing.