The study of urban interaction based on modified gravity model —A case of Changsha-Zhuzhou-Xiangtan

In this paper, Gravity Model was modified by discussing its urban quality and distance parameters, and the dynamic change of urban interaction force in Changsha-Zhuzhou-Xiangtan urban agglomeration was also analyzed. The results show that: during 1999 to 2009, the urban quality of Changsha was relatively higher total level, and fluctuated smaller, than Zhuzhou and Xiangtan. Meanwhile, the intension and changes of urban interaction force between Changsha and Zhuzhou or Xiangtan were larger, but steadier and lower level between Zhuzhou and Xiangtan city. They also reflect that urban quality is influenced by many factors, not just decided by GDP, population and other single index, and Changsha has stronger advantages of competitiveness and development so that it plays an obvious core rule in internal urban agglomeration. Therefore, in the future, the urban agglomeration should improve urban qualities and reduce the cost of distance to enhance their interaction among cities.