OSMLR is a concept Mapzen has developed to provide linear referencing of OpenStreetMap road data. OSMLR stands for OpenStreetMap derived Location Referencing. OSMLR provides a stable linear-referencing system atop the ever-changing network of roadways in OpenStreetMap. It also allows systems to work across several different versions of OpenStreetMap derived data. OSMLR is based on OpenLR, a concept developed by TomTom.

We will discuss how we define and generate a set of OSMLR segments and reference external data sets (in particular Valhalla routing systems). We also discuss how to migrate and update OSMLR as OSM data edits occur. We also plan to discuss several possible uses - with focus on how these segments are being used within the Open Traffic project. Within Open Traffic, we use map-matching of GPS traces from data providers to report and store speeds along OSMLR segments and intersection transition times between segment pairs.

OSMLR as well as Open Traffic are open-source projects:

• https://github.com/opentraffic
• https://github.com/opentraffic/osmlr

This concept and implementation was developed by Matt Amos, Kevin Kreiser, and myself.