Location Referencing: TMC, Alert-C

Location Referencing: TMC, Alert-C

The ALERT-C protocol is designed to provide mostly event-orientated road end-user information messages. RDS-TMC messages are language-independent, and can be presented in the language of the user’s choice.

In a prevoious post I introduced different ways in which geospatial information can be shared between different persons. Now I will focus on the case where we use pre-coded locations. Let’s remind that we are dealing with a situation where the actor A wants to communicate an information related to his map to anoter actor B having a different map. The strategy we are going to describe is to share a common predefined set of locations that each actor can relate to his map. In that way any data referred to such set can be transmitted between the two actors unambigously.

The most common used system of pre-coded locations is the RDS-TMC using Alert-C as defined by the standards ISO 14819–1:2013ISO 14819–2:2013ISO 14819–3:2013ISO 14819–6:2006.

The ALERT-C protocol is designed to provide mostly event-orientated road end-user information messages. RDS-TMC messages are language-independent, and can be presented in the language of the user’s choice. The ALERT-C protocol utilises a standardised Event List of event messages with their code values, which also includes general traffic problems and weather situations. ALERT-C defines two categories of information within messages: basic and optional items. In principle, basic information is present in all messages. Optional information can be added to messages where necessary. Standard RDS-TMC user messages provide the following five basic items of explicit, broadcast information:

  • Event description, giving details of road event situation, general traffic problems and weather situations (e.g. congestion caused by accident) and where appropriate its severity (e.g. resulting queue length).
  • Location, indicating the area, road segment or point location where the source of the problem is situated.
  • Direction and Extent, identifying the adjacent segments or specific point locations also affected by the incident, and where appropriate the direction of traffic affected.
  • Duration, giving an indication of how long the problem is expected to last.
  • Diversion advice, showing whether or not end-users are recommended to find and follow an alternative route.

In addition to such basic information there are also optional ones, and among them we can find:

  • Road class and road number
  • Road segment
  • Area, region and country
  • Pre-assigned diversion advice

In the ISO 14819–1:2013 standard all these information are fully described and you can find exactly the binary content of the message bit per bit. While the ISO 14819–2:2013 standard defines the “Events List” to be used in coding the messages. Such list is composed by carefully selected English phrases for describing many type of events, and the corresponding translated phrases in other languages are officially available from the TMC Forum website. All listed events are identified by a numerical code to which correspond the phrase describing the event. The Event List also contains several predefined combinations of single phrase events and they are not always word for word identical to the corresponding phrases used in the single events. Binding words or small changes to the wording are necessary.

alert-c location-reference traffic rds-tmc maps c++

Bootstrap 5 Complete Course with Examples

Bootstrap 5 Tutorial - Bootstrap 5 Crash Course for Beginners

Nest.JS Tutorial for Beginners

Hello Vue 3: A First Look at Vue 3 and the Composition API

Building a simple Applications with Vue 3

Deno Crash Course: Explore Deno and Create a full REST API with Deno

How to Build a Real-time Chat App with Deno and WebSockets

Convert HTML to Markdown Online

HTML entity encoder decoder Online

References in C++ Example | C++ References Tutorial

References in C++ Example Tutorial. References are somewhat similar to pointers but not. References declared a second name to the existing variable.

C++ Map Example | Map in C++ Tutorial (STL)

C++ Map is a dictionary-type associative container, also known as holder objects in the C++ STL. The Map as the name suggests storing the values in a mapped fashion.

Google Maps Location Sharing Not Updating

In this blog post, I will discuss how to fix google maps location sharing not updating or not working and also will unable to refresh Google maps sharing location issues. By using Google location sharing features you can choose who can find your current location for what length of time. It is important to show the updated location that you can share with your family or friends so that they can receive you or show you the right path to access at your right location simply.

Dicey Issues in C/C++

C/C++ problems. If you are familiar with C/C++then you must have come across some unusual things and if you haven’t, then you are about to. The below codes are checked twice before adding, so feel free to share this article with your friends.

A handy reference to C conversion specifiers and modifiers

C conversion specifiers and modifiers. A handy reference to C conversion specifiers and modifiers