Dr. S. Lotfi
Urban network is one of the most important land uses which determine the form and efficiency of other land uses. The urban users of many developing countries are preceding the urban transport construction which it leads to high traffic congestion. North of Iran suffers from high seasonal traffic congestion due to tourist function of the area beside the southern coast of the Caspian Sea. This paper attempts to illustrate the congested sites of the town and then propose some traffic solutions by applying Arc-view GIS.
Introduction In recent decades, Iran has experienced very high growth rate of urban population. And the production of private cars has been triplet during last fifteen years (N.S.C of Iran, 2005). So the most evident feature of such trend is the urban road congestion i.e. the waste of time and energy. This study tries by selecting a type of urban public transport, taxi, to evaluate the efficiency of urban transport system in a small town.
Geographic Information Systems (GIS) have long been recognized as a valuable tool for the representation and analysis of transportation networks and related activities. GIS have proven to be an integral tool in addressing the needs of transportation managers. Through the well-established vector data structure, GIS has provided an efficient means for organizing basic transportation related data in order to facilitate the input, analysis, and display of transport networks. GIS for Transportation (GIS-T) is a broad expression that encompasses all of the activities that involve the use of Geographic Information Systems for some aspect of Transportation planning, management, or science. GIS-T applications can be used to monitor traffic accidents that have occurred in the past, or they can plan for changes in the transportation network design for the future. In recent, the ArcGIS TM transportation data model has designed for NewYork (ESRI, 2001). The research aims to use it for the present case area.
Transportation and GIS
GIS for Transportation is a broad expression that includes all of the activities that involve the use of Geographic Information Systems for some aspect of Transportation planning, management, or science (Miller and Shaw, 2001; Hutchinson and Daniel, 2000). Government agencies, research institutions, and members of private industry are just some of the entities that routinely build T-GIS applications. These applications can involve any mode of transportation (truck, automobile, train, ship, taxi, airplane, etc.), or may consider other transportation related objects such as pavement, stop signs, or construction equipment. T-GIS applications can be used to monitor traffic accidents that have occurred in the past, or they can plan for changes in the transportation network design for the future. The breadth of the field of T-GIS provides many opportunities for the development of new and innovative applications, and at the same time presents challenges to those who will try to integrate such diverse activities. In short, there is a large and diverse base of users for T-GIS.
They have different objectives toward which they work, and they have different constraints on the transportation activities they can conduct.
In order to describe the structure of a database, it is required to know the concept of data model. A data model is a collection of conceptual tools for describing data, data relationships, data semantics, and the data constraints. Each of these models represents a structure that has been accepted by a group of users, and each must be respected for its utility. The development process of the ArcGIS Transportation Data Model has benefited from each of these models and seeks to provide a structure that can integrate with any of them.
ArcGIS Transportation Data Model
The ArcGIS Transportation Data Model is designed to help in the development of transportation applications. It does so by providing a context within which a transportation system can be described, and assisting in the development of a geodatabase. The ArcGIS Transportation Data Model has a primary focus on the needs of organizations that manage road transportation networks (Booth and Mitchellet al, 2001) Here I attempted to understand and reflect transportation GIS for the present project to provide a practical, essential ArcGIS Data Model. A data model for transportation is necessarily complex due to the many and varied uses of transportation data (Brail and. Klosterman, 2001; Lee and Wong, 2001). For most urban organizations, management of their infrastructure with the purpose of reducing costs and improving customer service within their organization are very important. Transportation systems are unique in the sense that every land use and organization that interacts with the transportation network needs essential information about the transportation system(s) for their own routing, planning, and so on.
Implementing the ArcGIS Transportation Data Model
The following steps describe the process of designing the ArcGIS transportation data model:
- The Analysis Diagram can be used as a template to make initial decisions about which objects to use and how to organize them into a logical structure that is appropriate for the applications being developed.
Both the Analysis Diagram and the UML Diagrams representing the ArcGIS Transportation Data Model were generated in the Visio 2000 Software Package. Exporting the UML to a Microsoft Repository within Visio 2000 Creating a new Personal Geodatabase in ArcCatalog in which the empty schema will be created. Once the empty geodatabase schema has been created the geodatabase must be populated with transportation related data before the ArcGIS Transportation Data Model can be implemented in an application.
Final result is a geodatabase that is used to managing the transportation network.
This paper introduced the ArcGIS transportation data model for Babolsar town network. The following conclusions can be made:
- Through the well-established vector data structure, GIS has provided an efficient means for organizing basic transportation related data in order to facilitate the input, analysis, and display of transport networks.
- The ArcGIS Transportation Data Model is designed to help in the development of transportation applications. It does so by providing a context within which a transportation system can be described, and assisting in the development of a geodatabase.
- The ArcGIS Transportation Data Model is takes advantage of the flexibility of Object Orientation to define entities and the relationships among those entities.
- It showed that the arrangement of different urban land uses overlap each other and so create many traffic problems in the central areas of the town.
- The research recommends the construction of a new belt-road in the southern part of the town to alleviate the volume of private vehicles entering the city centre.
- The study revealed that the existing taxi stations are not distributed with respect of the volume of the travelers who cross the town in all directions.
- ESRI (2001) ESRI and Regents of the University of California,”ArcGIS Transportation Data Model (Draft)”, 2001.
- N.S.C (2005) National statistical centre of Iran, Tehran. No 12 , pp 16-18.
- Booth, B., A. Mitchell, et al. (2001) Getting started with ArcGIS : GIS by ESRI. Redlands, CA, Environmental Systems Research Institute.
- Brail, R. K. and R. E. Klosterman (2001) Planning support systems : integrating geographic information systems, models, and visualization tools. Redlands, Calif., ESRI Press.
- Hutchinson, S. and L. Daniel (2000) Inside ArcView GIS. Albany, N.Y., OnWord Press.
- Lee, J. and D. W. S. Wong (2001) Statistical analysis with ArcView GIS. New York, John Wiley.
- Miller, H. and Shaw, S-L. (2001) Geographic Information Systems for Transportation: Principles and Applications, New York: Oxford University Press.