DD CEN ISO/TS 24530-4:2006 - Page 2

Traffic and traveller information (TTI). TTI via transport protocol experts group (TPEG) extensible markup language (XML). tpeg-ptiML | Status: Current

1 Scope This document establishes the XML encoding of the method of the Public Transport Information application. The Public Transport Information Application is intended to cover all modes of public (ie collective) transport as well as inter-urban and intra-urban travel. The application itself is designed to allow the efficient and language independent transmission of public transport information either directly to an end-user, be it the public or another service provider, such as broadcasters, service operators or other information disseminating points or centres for onward transmission. TPEG-PTI aims at describing “legs” of a journey also described as “rides” by other methodologies. However, it is important to note that TPEG-PTI is not limited to describing single services, because it also allows the more general description of route, service and area wide problems. Public (or collective) transport information is usually consumed in one of four principle ways, and in TPEG-PTI these are labelled views, they are somewhat an analogue to:

• - Leader board information as used at stations or terminals
• - A report on the state of a network
• - The description of an individual service
• - As a news flash report

While the elements needed to produce information for any one of these four “views” are largely germane across the presentations, the end-user focus of TPEG applications is seen as useful to be able to mimic presentations, to which end-users are accustomed. TPEG-PTI views are intended to present information to end-users in a way that they are accustomed. TPEG-PTI messages can therefore group data elements to present one of the following views:

• - Incident Report View
• - Station/Terminal View
• - Route View
• - Individual Service View

It is important to bear in mind that these “views” are merely presentational aides; they have little to do with the content in the individual data elements. They do, however, indicate how data elements must be grouped if a presentation in any of these views is intended. Unlike the TPEG-RTM application, TPEG-PTI benefits from the nodal structure of public transport, making use of its discrete start, end and stopping points as well as being limited to fixed, be it real or virtual, routes. It is vital, for further understanding of this document, to have more than a passing understanding of the TPEG-PTI Binary specification which describes, among other things, in a step-by step approach: Message Management, Report views and how they are structured hierarchically to provide a full Public Transport Information message together with the TPEG Location Referencing system.