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Enterprise GIS approach for urban transportation planning
 Balamohan N SP eResources Pte Ltd, Singapore nbalmohan@rediffmail.com
Introduction Over the last decade planning authorities in developing countries moved from conventional approach to integrated approach in urban planning activities. Geographic Information System (GIS) has become most promising technology for the integrated approach. In spite of the technology, the terms ‘haphazard urban growth’, ‘irregular pattern’, ‘rapid urbanisation’ have become very common among urban planners. This is because, lack of reliable information flow on time during the planning stage both in evaluating current transportation projects and proposed solutions. Though the GIS technology has made planning easy and reduces the complexity in the traditional planning process. The problems are due to sequential impact of the implementation of GIS technology in project level rather comprehensive level. This paper attempts to present the implementation of enterprise GIS concept in the area of urban transportation planning. This paper covers two major topics. First the concept and components of enterprise GIS with the real life example adopted in State of Qatar. Secondly it explains the linkage between the supply and demand side components of transportation planning with GIS. The overview of interfaces and analysis tools developed using the Qatar’s enterprise GIS Model has also presented in this paper. Enterprise GIS The concept of enterprise GIS is to maximise the utilisation of GIS capabilities by channelising timely spatial and non-spatial data from various source with in a government/organisational setup. In the beginning of 1989, State of Qatar identified the potential for enterprise GIS, and now it is one of the most successful examples that implements enterprise GIS at national level. The Qatar enterprise GIS Model focuses on the common GIS requirements of spatial, non-spatial data and applications for inter/intra government agencies. The model determined that the following are the key components for the implementation of enterprise GIS;
Role of ArcInfo and emme/2 Network and Land data can be easily developed, maintained and updated in GIS database. Transportation Planning and management needs accurate and timely spatial and non-spatial information like, network, capacity, speed restriction etc., to assist planning activities. Most importantly GIS database maintains and provides topological relationship (connectivity and contiguity), which plays key role either in macro or micro level transportation planning analysis. Standardisation and Data Sharing are the two components provided strong support for implementing the enterprise GIS in urban transportation planning. Arc/Info and emme/2 are the two system employed respectively for GIS and transportation planning/modeling. ArcInfo is the comprehensive GIS suite capable to create, manage, analyse and present the geographic and attribute information in a more systematic and consistent way. emme/2 is a state-of-art graphical software tool for multimodal transportation planning. This system helps transportation planners, to model transportation network and assign the generated traffic under given set of conditions. There is close relationship in terms of data model between Arc/info and emme/2 has been identified for supply and demand side components of transportation planning. In both the packages, the network model constitutes with series of nodes and links, however different terminology is used. These node and links are complemented with set of system-defined and user-defined fields. Both network models adopt network topology e.g., there is no need to create additional node at the intersection of a road and flyover. However one major difference between the data model is that the links in Arc/Info by default are in bi-directional, but in emme/2 each link represents uni-direction along the direction of link e.g. a two-way street is represented with two arcs in emme/2. The demand side information is linked with a spatial entity called traffic analysis zone (TAZ). The TAZ is maintained in polygon feature class in the GIS environment.  Fig 1: illustrates the concept of data sharing adopted in the Qatar's enterprise GIS Approach for transportation planning and modelling Supply Side - Network Extraction Tool Basically transportation network and road inventories are the major supply side information for transportation planning and modeling. The following GIS functions are identified as more critical for the supply side data model to carry out traffic assignment / simulation:
The interface developed to extract supply side components for transportation planning has four modules. The modules are:
This interface provides two data files formatted for batch inputting in the emme/2 module 2.11 (network batch input) and 2.31 (turn restriction batch input).
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