ITS Standards Fact Sheets
SAE J2266 - Location Referencing Message Specification (LRMS)
This Fact Sheet was written on November 22, 2005.
The status of the standard at the time was:
Published in October 2004.
This Fact Sheet was last verified on October 14, 2009
Check the ITS Standards Search to see if there has been subsequent development activity.
The Location Referencing Message Specification (LRMS) describes a set of standard interfaces for the transmission of location references among different components of Intelligent Transportation Systems (ITS). The LRMS facilitates the movement of ITS data containing the attribute of location; typically, but not always, on a transportation network. LRMS interfaces define standard meanings (semantics) for the content of location reference messages, and standard, public domain formats (syntax) for the presentation of location references to application software. Location references must be communicated in an unambiguous and mutually understandable way. LRMS interfaces, when incorporated into relevant standards, will provide a common language for the expression of location among the different components of an integrated transportation system. Since different kinds of location referencing methods must be supported for ITS applications, a variety of location referencing data concepts are provided within the LRMS.
The original work on location referencing was documented in an SAE Information Report, SAE J2374, also called Location Referencing Message Specification. This newer standard, SAE J2266, Location Referencing Message Specification (LRMS), supercedes the Information Report. The original LRMS approach defined seven "profiles", which are sets of primitive data elements that, when taken together, describe a location according to a particular location referencing method or combination of methods. Examples of referencing methods used to convey locations are complete addresses, geographic coordinates, and offsets along known roads or links.
This standard, SAE J2266, maintains the profile concept, but allows constituent parts of the referencing structure of each profile to be used in other profiles, or even directly by applications. This allows for more reuse of common data elements, and therefore more flexibility in location specification.
The necessity for multiple profiles is driven by the diversity of location references within operational, integrated ITS systems. For example, as defined by the National ITS Architecture, the location of a traffic accident could be communicated directly or indirectly from a police vehicle or private cell-phone to a central information service provider (ISP) site. During this process, the location of the accident and its impacts could be expressed in a variety of ways, since what is appropriate for a police vehicle may not be appropriate for a central site or for a private automobile. Also, historical, modeling, or other data may be obtained from other databases within an agency, and combined with data from other sources. Thus, location referencing can occur between both internal and external system components and interface standards are required for successful and efficient deployment.
What are these standards for?
This standard SAE J2266, Location Referencing Message Specification (LRMS), describes seventeen LRMS profiles. Profiles are defined for commonly cited location referencing methods and for particular application communities that have unique requirements. For example, the Grid profile contains a built-in compression scheme, and thus provides an efficient mechanism for transmission of location information over bandwidth constrained media. An ITS location reference may use a single profile, or several profiles. The seventeen profiles described are:
- Address Profile - address information that uniquely describes a location, such as a postal code, structure number (e.g., houses), street direction, street side, etc.
- Area Location Profile - references an area such as a town, city, state, county, or region.
- Chain Profile - references sequences of links with distinct start and end nodes, direction, and name, such as a jurisdictional boundary (e.g., county line, town line, or state line).
- Cross Streets Profile - specifies a link along a street or road by names and/or coordinates of bounding intersections with other streets. Note that this profile supercedes SAE 1746, the ISP-Vehicle Location Referencing Standard.
- Geographic Coordinate Profile - references coordinate-based points, links, or polar coordinates.
- Geometry Profile - referencing for geometric (geometric coordinate-based) objects including nodes, points, links, chains, transitions, areas, and polygons
- Grid Profile - similar to the Geometry profile, but includes a built-in compression scheme intended for use in bandwidth constrained situations
- Group Location Profile - references a group (set) of locations; used if the same information applies to all locations within the group
- Linear Reference Profile - identifies a location on a network by distances along transport elements (e.g., road, ferry, railway, etc.) from known locations on the network, such as mileposts.
- Link Location Profile - references a logical or physical link
- Node Attribute Profile - associates information about a node to a given node
- Point Location Profile - references point locations, including non-topological (occur anywhere), or nodes (e.g., intersections, intermodal network connections)
- Pre-Coded Profile - location information that has been pre-coded into tables for efficiency of use
- Public Grid Profile - references by the U.S. National Grid System, by State Plane Coordinate Systems, and by local reference grids.
- Route Location Profile - references routes as a collection of points and links treated as one location (e.g., a bus route)
- Spatial Object Profile - associates information (attributes) with a spatial object, such as points, nodes, links, chains, etc.
- Transition Profile - references to transitions, such as connections between two chains of the same mode (e.g., turn lanes and exit ramps)
Who uses them?
This standard is intended for use by ITS system developers, designers, geographic information system vendors, vehicle navigation map database providers, or any person or organization wishing to use standard interfaces for location referencing.
How are they used?
This standard SAE J2266, Location Referencing Message Specification (LRMS), is the baseline standard for common location referencing methods, formats, and definitions; it is the "family" of location referencing options. Conformance to the LRMS is achieved by subsetting, both at the level of profiles and sub-profiles, and also at the level of data elements. System developers may use it to help in the selection of profiles for use in ITS applications of either internal or external interfaces. By allowing a choice from multiple location referencing profiles, the LRMS standard allows data servers, software developers, and users to work using the system most relevant to meeting their equipment and interface needs.
This standard SAE J2266, Location Referencing Message Specification (LRMS), is intended to provide a practical approach to standardization for location referencing within a mixed data set environment, i.e., where more than one kind of spatial data set exists and where spatial references between these data sets must be made. Although some ITS applications in local areas may be satisfied by having one common data set for which location references may be implemented in any number of ways, many ITS applications will have broad interoperability requirements within the nation or a region. For example, a vehicle driven from California to Florida should be able to receive and understand spatial references for traffic information or routing instructions throughout the trip. Similarly, information sent from a vehicle to a central ISP site should be understood in any city, state, or region regardless of the kinds of data sets in use, whether they are public or private, or how locations are referenced internally to particular data sets. The LRMS can be applied to ITS systems involving vehicles on roads, rails, and waterways. It can also be applied to location references between central sites and non-mobile sites such as kiosks, other central sites, or pedestrians, as well as within centers and ISPs. The broadest scope of the LRMS is, therefore, intermodal spatial data set interoperability at the national level and across all ITS applications.
The following ITS standards are related and should be considered when using this standard:
- IEEE 1489-1999 - Standard for Data Dictionaries for Intelligent Transportation Systems - Part 1 Functional Area Data Dictionaries
- IEEE Std 1488-2000, Standard for Message Set Template for Intelligent Transportation Systems
- SAE J2354 - Message Set for Advanced Traveler Information System (ATIS)
- SAE J2369 - Standard for ATIS Message Sets Delivered Over Reduced Bandwidth Media
The following standards and documents, while not part of the ITS standards, should also be considered when using this standard:
- ISO/IEC 8824-1 -- Information technology - Abstract Syntax Notation One (ASN.1): Specification of basic notation
- ISO/IEC 8824-2 -- Information Technology - Abstract Syntax Notation One (ASN.1): Information Object Specification
- ASN.1:1997 - Abstract Syntax Notation One
- ISO/IEC 8824-3 -- Information Technology - Abstract Syntax Notation One (ASN.1): Constraint specification
- ISO/IEC 8824-4 -- Information Technology - Abstract Syntax Notation One (ASN.1): Parameterization of ASN.1 specifications
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