Accessibility Evaluation Of Ports And Hinterland Cities Based On Improved Gravity Model

With the continuous construction and development of China in various fields,it is playing an increasingly important role in the globalization.The rapid development of related fields such as freight transport and trade export has brought about the growth of regional economy,the continuous improvement of transportation,the high-speed construction and development of urban agglomeration and the intensification of urbanization process.All this makes the communication between ports and hinterland cities more and more close: domestic and foreign trade demand,hinterland cities’ demand and supply capacity will affect ports;Regional development situation planning,the type and scale of cargo handled by ports and so on affect hinterland cities.Transportation breaks the space barrier between ports and hinterland cities,connects them,and makes them have multiple choices and more possibilities for development.Accessibility is an important evaluation method reflecting the connection between ports and hinterland cities.From the perspective of accessibility,this thesis calculates and evaluates the accessibility of ports and hinterland.First of all,it summarizes and analyzes the research on accessibility by domestic and foreign scholars.After sorting out the research problems and research directions that can be further studied,it proposes the research contents and methods of this thesis.Secondly,the relevant concepts and theoretical basis of accessibility are introduced,which provides theoretical support for the improvement and evaluation of accessibility model.Then,different methods of calculating accessibility are compared and the gravity model is selected.The original gravity factor is improved according to the characteristics of ports and hinterlands,and the original impedance factor is improved according to the characteristics of traffic,and the index system is aggregated into gravity factor by appropriate methods.Finally,an empirical study is carried out in a certain range to calculate the accessibility of ports and hinterland cities,and evaluate the accessibility according to the characteristics of transport accessibility.It is found that the gravity model is suitable for studying the accessibility of ports and hinterland cities.The two spatial interaction forces of the improved gravity model are defined by the port attraction index system and the hinterland city influence index system respectively.The impedance factor of the improved gravity model is the distance after considering the actual road network construction and driving conditions.The attractiveness of ports is mainly measured from the handling capacity and infrastructure,while the influence of hinterland cities is mainly measured from the economic aggregate,industrial structure and development quality.When the port attraction index system and hinterland city influence index system are aggregated into forces,the weight calculation by CRITIC method can retain the maximum amount of information and reflect the characteristics of the original index system.After calculating the traffic accessibility of ports and hinterland cities,we evaluate the traffic accessibility from the perspective of the spatial relationship between ports and hinterland.Then,taking ports and hinterland cities as cross sections,the thesis evaluates the traffic accessibility from the perspectives of social and economic characteristics,spatial characteristics and time characteristics.Based on the empirical research,to evaluate the accessibility,the following conclusion:under the spatial characteristics,traffic accessibility as opposed to a port hinterland of the geographical position,if there is a traffic hub ports around the city,traffic accessibility and the construction of the hinterland of regional traffic network connection,the location in the hinterland cities in urban agglomeration;From the perspective of social and economic characteristics,the correlation between transport accessibility and its own influence and that of hinterland cities is different.The social and economic characteristics of ports and hinterland cities are related to the trade positioning that they play a role in different transport objects and play a role according to geographical advantages.The temporal evolution of transport accessibility is related to domestic and foreign trade situation,transport network construction,local and regional development orientation,and the impact of emergencies.