Review of the methods of delimitation for the spatial scope of urban agglomeration

The delimitation of urban agglomeration region is a critical issue in urban studies. But there are no standard methods so far for the delimitation. Starting with the concept of urban agglomeration, this paper reviews the methods of the delimitation of urban agglomeration region. We sum up two types of the methodology of the delimitation of urban agglomeration region. We compare and analyze a variety of promising and representative methods such as the key indicators distribution analysis, radiant ability of central city-based analysis, modeling analysis, multi-factor overlay analysis and spatial correlation analysis. Based on such, the common characteristics of the existing methods are abstracted and further developments are discussed. Finally we conclude that the analysis based on the functional zones, emphasizing the relations between the cities and the mode of combining qualitative analysis with quantitative analysis are the developing trends of the method. Facing to the more emergences of the polycentric urban agglomeration and the network urban agglomeration, the method combining spatial statistical analysis based on GIS with the analysis of the flow data among cities would be a better choice for the delimitation of urban agglomeration region.