Location Referencing Standard registered at Approval Stage

Sources: ISO TC 204, AGORA-C [1], AGORA-C [2], ITS Standardisation Activities in Japan

The ISO Standard, ISO / FDIS 17572 Parts 1-3, "Location Referencing for Geographic Databases", has been upgraded from the “Enquiry Stage” of Draft International Standard (DIS) to the “Approval Stage” of Final Draft International Standard (FDIS). This is the final stage before publication.

The standard is concerned with ensuring compatible location referencing between different geographical databases so that when information is exchanged between different applications or systems with different geographic databases, they are able to identify locations accurately.

Geographic information forms a major part of the information that is communicated in ITS applications. The answer to questions, such as ‘Where am I?’, ‘Where are you?’ and ‘Where is the accident?’ depends on the type of spatial reference system used. The reference system can be in terms of co-ordinates relative to an origin, or in terms of objects of direct human experience, such as a road intersection, a point of interest or a section of a road. Location-related traffic information is contained in a traffic message, which is created in the sending system, transmitted and then used in the receiving system. The sending and receiving systems may, and often will, use map databases of different origin, specification and completeness.

Standardisation efforts initially concentrated on a method based on co-ordinate systems and road descriptors.  However in 2000, ISO TC204 Working Group 3 ITS Database Technology launched discussions on a more comprehensive standard, after the process had been stalled for some time.

The ISO / FDIS 17572 standard, developed in Working Group 3, is made up of the following parts:

o        Part 1: General Requirements and Conceptual Model

o        Part 2: Pre-coded Location References (pre-coded profile)

o        Part 3: Dynamic Location References (dynamic profile).

It considers two different methods for location referencing. The first method “Pre-coded Location Referencing”, assumes common pre-coded tables like the European Traffic Message Channel (TMC) or the equivalent Japanese Vehicle Information and Communication System (VICS). The second method, “Dynamic Location References”, varies in real-time and has evolved from the European “AGORA-C” proposal, developed in the European Commission’s Fifth Framework AGORA Project (implementAtion of Global lOcation Referencing Approach).

The AGORA-C method works by encoding locations on the road network, such as intersections and road sections. The AGORA project description states that "the algorithms comprise the following functionality:

o        Identification of a location

o        Creation of the location reference

o        Encoding for and transmission in a message

o        Reception and interpretation of the location reference

o        Presentation of the location to end-users."

As a dynamic method, AGORA-C anticipates differences between map versions at the time of decoding and intelligently snaps to the corresponding map location when placed on a target map. To deploy AGORA-C geo-coding may require using an encoder and decoder; alternatively components can be designed either as embedded software or as a web service.

ITS Radar International will monitor developments

Keywords: Geographic information, Standard