Acta Geographica Sinica ›› 2010, Vol. 65 ›› Issue (12): 1534-1547.doi: 10.11821/xb201012009

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Studies on Spatial Analysis Method of the "Pole & Axis System": A Case Study of the Yangtze River Delta

ZHANG Li, LU Yuqi   

  1. College of Geographical Science, Nanjing Normal University, Nanjing 210097, China
  • Received:2010-01-16 Revised:2010-07-20 Online:2010-12-20 Published:2010-12-20
  • Supported by:

    National Natural Science Foundation of China, No.40771075; Natural Science Foundation of the Jiangsu Higher Education Institutions, No.10KJD170001

Abstract: Since the theory of "Pole & Axis System" was proposed, great achievements have been made in its theoretical expansion and practical application. With the development of GIS and the wide application of spatial analysis techniques, further research of the theory of "Pole & Axis System" depends on innovation of regional spatial analysis methods and techniques. Based on the "Pole & Axis System" theory proposed by Professor Lu Dadao, a spatial analysis method of "Pole & Axis System" was introduced. The method combines point elements, including town node, traffic node (port, airport, railway station, highway intersection) with linear elements (waterway, railway, highway, land way) of regional spatial structure in various ways and analyzes the spatial accessibility and the spatial diffusion. It takes linear elements as diffusion route to analyze gradual diffusion of point elements and calculate spatial accessibility of "Pole & Axis System". "Pole & Axis Gradual Diffusion Model" is constructed as time-distance attenuation diffusion model according to exponential and linear diffusion pattern. Also the model selects "Weighted Average Travel Time" as evaluation indicator of spatial accessibility and adopts the minimal seed algorithm to calculate minimal travel time and shortest path from one cell to others in the region. Based on GIS, "Pole & Axis" spatial analysis information system is developed, in which several common formations of "Pole & Axis System" are simulated. Also spatial pattern and evolution of node diffusion and accessibility are analyzed. A case taking Yangtze River Delta as a test region is presented. It chooses 16 cities as point elements and uses land traffic network of 1985, 1995, 2006 and 2020 as axis elements. The case studies axial gradual spatial diffusion of city nodes based on land traffic network of different periods and generates diffusion maps of score and accessibility of every city node for different periods. The results show the following aspects: Firstly, diffusion scores and regional accessibility values of city nodes are increasing every year. Secondly, spatial diffusion is evolving from multiple cores into a single one and the diffusion axis is apparent. Thirdly, the Yangtze River Delta region is integrated gradually, but the disequilibrium between regions is enlarged. Finally, the "Z"-shaped high-speed traffic corridor of Nanjing, Shanghai, Hangzhou and Ningbo is formed.

Key words: "Pole &, Axis System", spatial analysis method, time-distance attenuating diffusion model, weighted average travel time model, Geographical Information System, Yangtze River Delta