OpenLR

OpenLR is an open standard for encoding location references on road networks to enable map-agnostic interchange of location data across navigation systems and map providers. It is designed to support sharing of incidents, routes, and points of interest without requiring identical map content.

The specification was developed as an open standard by the OpenLR Alliance, originally with contributions from major map and navigation companies. It defines a portable representation of a location reference that can be encoded and decoded against different map datasets.

The core concept is to describe a location as a sequence of Location Reference Points (LRPs) that run along the road network. Each LRP conveys descriptive information such as the approximate position on the road, the road class, form of way, and a bearing, plus a distance to the next LRP. The combination allows a receiving system to locate the reference on its own map by matching the LRPs to its road topology.

OpenLR supports various reference types, enabling compact encoding of short or long segments, from a single point on a road to longer routes. The encoded data can be transmitted as a compact string or structured data and is intended to be independent of a particular map provider.

Applications include traffic information, incident reporting, fleet telematics, and map-to-map interoperability. Implementations exist in multiple programming languages, and several map vendors provide OpenLR-compatible tooling and libraries.

Limitations include dependence on compatible map data and alignment; accuracy depends on the quality of the reference data and map matching; it is a referencing mechanism rather than precise coordinate encoding.