TomTom has developed a dynamic location referencing technology as an open standard for the navigation, mapping and ITS Industry, called OpenLR.
Location Referencing and OpenLR:
The process of encoding a location is called Location Referencing. This assumes a map on the sender side from which the location is encoded and a map on the receiver side in which the decoded location is found back. An obvious way of Location Referencing is using geographic coordinates. One important disadvantage of using coordinates is that it needs identical maps at both sides of the communication chain which often is not the case. As a consequence, the decoded location may not be found back in the receiver map, or decoding (i.e. map-matching) may be inaccurate or ambiguous.
OpenLR is a method for location referencing which does not have this disadvantage. It accommodates requirements of communication of location between systems which have dissimilar maps. OpenLR is communication channel independent. It takes bandwidth requirements into account in the sense that OpenLR requires minimal bandwidth.
OpenLR has been designed for the use case of transferring traffic information from a centre to in-vehicle systems, built-in or used as an add-on (PND, Smart Phone). The information transferred can consist of the current traffic situation at a certain location, a traffic forecast or special alerts. The corresponding locations are roads or a list of connected roads.
The most well-known and most used method to transfer traffic information today is called RDS-TMC. The Location Referencing used in RDS-TMC makes use of pre-coded locations. These pre-coded locations are added to the corresponding locations in the map by the map providers of the sending and the receiving map.
The process of encoding is looking up the location code in the map belonging to the relevant location. The process of decoding is finding back the location code in the map and looking up the corresponding location.
As RDS-TMC makes use of pre-coded locations, the amount of locations fit to be transferred is limited. OpenLR does not have that restriction. With OpenLR every location in a map can be transferred.
Dynamic location referencing is a requirement for many ITS and LBS systems and services. The use of various location reference methods will limit the interoperability of systems. A universal standard across a variety of applications will enable system integration and open the market for LBS.
The goal of OpenLR is the wide-scale adoption by the industry at large. OpenLR is therefore proposed as an open standard in an Open Source framework. It will be usable for anyone dealing with locations and transmitting these between systems having dissimilar maps. The current version of OpenLR focuses on line locations but can easily be extended to handle point and area locations.