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With the proliferation of mobile computing, the ability to index efficiently the movements of mobile objects becomes important. Objects are typically seen as moving in two-dimensional (x,y) space, which means that their movements across time may be embedded in the three-dimensional (x,y,t) space. Further, the movements are typically represented as trajectories, sequences of connected line segments. In certain cases, movement is restricted; specifically, in this paper, we aim at exploiting that movements occur in transportation networks to reduce the dimensionality of the data. Briefly, the idea is to reduce movements to occur in one spatial dimension. As a consequence, the movement occurs in two-dimensional (x,t) space. The advantages of considering such lower-dimensional trajectories are that the overall size of the data is reduced and that lower-dimensional data is to be indexed. Since off-the-shelf database management systems typically do not offer higher-dimensional indexing, this reduction in dimensionality allows us to use existing DBMSes to store and index trajectories. Moreover, we argue that, given the right circumstances, indexing these dimensionality-reduced trajectories can be more efficient than using a three-dimensional index. A decisive factor here is the fractal dimension of the network-the lower, the more efficient is the proposed approach. This hypothesis is verified by an experimental study that incorporates trajectories stemming from real and synthetic road networks. [ABSTRACT FROM AUTHOR]

One of the impediments to the implementation of ITS is the lack of map database interoperability. Centreline databases are available from a number of sources, but few were designed specifically for ITS. Consequently there are a variety of problems—coordinate inaccuracy, errors of omission and commission, missing or wrong street names, incorrect topology—that are compounded when communicating parties use databases from different vendors. Many ITS applications (e.g., emergency response, ATIS) rely on the exchange of messages in which location is a component. Map error and interoperability problems can result in a variety of practical difficulties, from inappropriate vehicle routing to delays in delivery of critical services. These problems can be addressed by (a) standards for map databases, (b) intelligent messaging, (c) national integration efforts to improve database quality in the long term. This paper examines the dimensions of the problem, and describes solutions currently under development. [ABSTRACT FROM AUTHOR]

Transportation systems exist to improve individual accessibility. However, emerging applications of GIS in transportation (GIS-T) and intelligent transportation system (ITS) focus on throughput (the amount of system flow) rather than accessibility. Throughput is related but not equivalent to accessibility. Sensitive transportation planning requires rigorous, realistic and tractable accessibility measures. This paper reports on the development of GIS software that implement space-time accessibility measures (STAMs). The STAMs reflect the benefits that individuals receive from the transportation system. They are easily interpreted, particularly with respect to changes in accessibility. The STAMs also consider the locations and travel velocities dictated by the transportation system as well as individuals’ daily activity schedules. Tractable computational procedures allow calculation of the STAMs for detailed, urban-scale transportation networks. A prototype ArcInfo$^\circledR$-linked software system that runs on Windows NT$^\circledR$ or Sun Solaris$^\circledR$ platform implements the STAMs with user-friendly interfaces and project management tools. [ABSTRACT FROM AUTHOR]

The evolution of GIS-T is characterized in three stages: the map view, the navigational view, and the behavioral view. The static nature of the map view favors applications related to inventory and description, and raises difficult questions of accuracy and interoperability. The navigational view adds concerns for connectivity and planarity, and the storage of time-dependent attributes. Navigation also raises issues of representation related to scale, including the need for lane-level connectivity. The behavioral view stems from the work of Hägerstrand, treating transportation events as dynamic and occurring within the largely static transportation space. Appropriate representations for the behavioral view have still to be worked out. In all three cases the legacies of prior technologies and perspectives are still evident. The paper presents a series of research challenges, dealing with standards, representation, unambiguous communication, economic models, response to new technologies, and application of knowledge gained from GIS-T and ITS research to other fields. [ABSTRACT FROM AUTHOR]

Disaggregate travel data is not new to urban transportation planning studies, but it is infrequently handled in a GIS environment. With the evolution of urban travel demand models from aggregate models to disaggregate models and from a trip-based paradigm to an activity-based paradigm, there is a growing need of managing disaggregate travel data with spatial and temporal components in a GIS environment. At the data organization level, the main challenge is to efficiently store the data by minimizing redundancy while maintaining the complex relationships among the data items. The data organization should allow users to retrieve and visualize disaggregate travel data according to various possible combinations of spatial, temporal, and attribute criteria. This paper presents an implementation that employs a relational database approach and dynamic segmentation to organize the spatial, temporal, and attribute components in a sample travel diary data set. Discussions of the benefits and shortcomings associated with this approach are provided, along with suggestions for future research. [ABSTRACT FROM AUTHOR]

This paper gives the definitions of transport telematics and intelligent transport systems (ITS), and describes the basic pre-conditions, situation and market of ITS as well as its applications (products and services) in Europe. Availability of navigable digital maps is emphasized as a major premise. Strategic aspects and key issues for ITS development are explained. Current weaknesses and prospects for ITS services in 20 years are discussed. It is concluded that ITS will make a major contribution to the sustainable development of our society, because it increases our mobility without additional environmental burdens. [ABSTRACT FROM AUTHOR]

Comments on transportation as one of the most important geographic phenomenon. Emergence of the term intelligent transportation systems; Exploration of the issue evolving rules for geographic information systems; Impact of the emergence of geographic information and intelligent transportation systems on the way people deal with transportation.