A Analysis Study Of Port City Expansion Along The Maritime Silk Road By Remote Sensing

In 2013,China proposed a major initiative to build the 21 st Century Maritime Silk Road.As an important node in maritime routes,port cities will face new opportunities for development.Port cities are located in a coastal zone with a complex ecological environment.It has gather both land and sea productivity,which is different from the general inland cities.According to the particularities of the port city and the opportunities,challenges and problems faced by the port city,this study selected 35 port cities along Maritime Silk Road,obtained land use information of port cities based on remote sensing.Analyzed the expansion rate,expansion characteristics and quantitatively evaluated the relationship between port and city of port cities from individual,regional,and overall levels.Compared the similarities and differences between the development processes of port cities in different regions of Southeast Asia,South Asia,West Asia,Africa and Europe.The main conclusions are as follows:(1)Based on the Landsat satellite imagery from 1990 to 2015,the land use and land cover information of 35 port cities was extracted by classification system of coastal zone and CART decision tree method,and analyzed the land use structure and urban expansion rate.The results showed that the vegetation coverage in Southeast Asia,South Asia,and Europe was dominated by farmland or forest land,and that in West Asia and Africa was dominated by shrubs and bare land.We have found that the urban area of the 35 port cities expanded exponentially,and annual rates vary between regions.The highest annual rate was 6.77% in Southeast Asia,and the minimum was only 3.85% in African,followed by South Asia,West Asia and Europe.The total urban land area of 35 port cities increased with an average annual rate of 4.85% from 1990 to 2015,and the average city-doubling time was about 15 years.(2)We analyzed the urban expansion of 35 port cities from landscape pattern,compared the expansion characteristics and expansion model(leapfrogging type,edge expansion type and infilling type)with landscape index of LSI,COHESION,DIVISION,AI,LEI and CI.Results showed that the development of port cities was not consistent in Southeast Asia.The capital port city has a stable and compact space structure,and it expanded synchronously in three type.The small and medium port cities have experienced the process of expansion from diffusion to aggregation.The development port cities was relatively compact in West Asia and Africa,its shape and landscape pattern was stable and regular.Expansion type was dominated by edge expansion type and infilling type.The shape of port cities was very complex in European,and its landscape pattern was basically stable.The spatial distribution of urban land was relatively concentrated,and expanded synchronously in three type.Our results generally supported the development process of port cities were consistent with diffusion-coalescence urbanization process,the changes in various landscape indexes indicated that the port city tends to be compact.The fraction of leapfrogging,edge and filling has changed form 4:4:2 to 3:4:3 during the past 25 years.(3)Based on the change of development phase and spatial structure of port cities,and the principles of spatial morphology,we have built the Port-City Relationship index(PCRI),and put forward three types of ideal port city spatial relationship model: central port city,edge port city and separate port city.We analyzed the distribution and changes of PCRI values in the 35 port cities and the three types during four periods.Result showed that there is a common trend in the spatial structure changes between ports and cities.With the development of cities,the dependence of cities on ports will gradually stable,the relationship between port and city will generally develop towards the edge of the port(PCRI = 0.6).(4)The analysis results from the average expansion rate of urban,the expansion characteristics and expansion model of port cities,the port-city spatial structure relationship,and the changes of port area all indicated that the development degree of port cities presents a pattern of east-west differentiation along the Maritime Silk Road.It is consistency in the development of port and city.The port cities in western regions such as Europe,Africa,and West Asia have developed earlier.They are more mature,have slower expansion rates,and a stable landscape pattern.The development of port cities in eastern regions such as Southeast Asia and South Asia are of varying degrees,and most port cities are rapidly developing.In the development stage,the expansion is fast and landscape pattern changes rapidly.Through accurate and regular monitoring of urban expansion of present and historical time in different regions,the inclusive and sustainable urbanization can be achieved.The well-organized monitoring strategy will also facilitate sustainable human settlement planning and management in all regions.Finally,when the sustainable development is achieved through port city development,the vision of the maritime silk route gets ratified and above all reflect the target of SDG-11.