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Locating socio-economic activities with GIS in Chines cities In the field of urban transport, location has been regarded as a key to integrate socio-economic data with transport data (e.g. Ries, 1995). A well-established location referencing system may facilitate transport data integration and data sharing. A GIS-T enterprise data model that incorporates transport features, transport events and other related attributes is necessary to meet the need of transport data sharing (Dueker & Butler, 1998; Dueker & Butler, 2000). The importance of referencing bases is also emphasized in building transport information systems. For example, Wright et al (2000) contend that road networks be divided into lowest common-denominator in order to build an integrated urban transport information system (UTIS). A closely related matter in location referencing is the accuracy of road centerlines that serve as referencing base in transport (Noronha & Goodchild, 2000). For most Western cities, although there are still uncertainties in location referencing, the referencing systems such as street address and postcode have been set up in a comprehensive way with relatively complete data. These systems can generally satisfy the needs of transport data processing. In most developing cities, however, there have been no consistent referencing frameworks, and data on referencing bases are incomplete. For example, postcodes in Chinese cities represent spatial areas that are too large to make any sense in location referencing. Street numbering scheme is theoretically systematic but its real application is confronted with many errors. Moreover, even these referencing data is available, the techniques of location referencing have to be adapted to meet the local requirements. The address expression in China is very different from the Western style, which frustrates direct application of the address matching process that is readily available in most GIS packages. This paper discusses these problems and proposes solutions in the context of China. Existing referencing methods are explored under the general rubric of two schemes: the street-based and the name-based scheme. An experimental implementation of these methods is presented based on data from Wuhan, a metropolitan city in central China. Institutional issues are discussed concerning data availability and data sharing in the context of Chinese cities. Methods of location referencing in China The process and schemes The process of location reference is to identify the spatial locations of socioeconomic activities in the context of geographical base, i.e. to assign spatial coordinates to the activity sites. The structure is shown in Figure 1. 
Figure 1 The process of location referencing People usually express a location in quite different ways. In a trip survey, for example, some may provide street address as required, some may have no idea about street number but may give their institution names, and some may only be willing to give a general description on the place where they are from. A location reference system should be able to cope with these situations and find correctly the activity sites. |