Dynamic analysis of urban spatial expansion and its determinants in Xiamen Island

Most of the world＇s cities are concentrated in coastal areas. As a special geographical component of the coastal system, island urban spatial expansion is the outcome of interactions between city development and the physical environment. This paper takes Xiamen Island, located in Southeastern China, as an example to analyze island urban spatial expansion and its determinants by combining an analysis of the literature on urban development policies, urban overall plans, population growth and industrial development, with geographical information analysis using historical maps and remote sensing photographs. Firstly, we reviewed the history of the Xiamen City development during the last 100 years, which can be divided into four periods： the embryonic modern city and early development from 1908 to 1949; administrative boundary expansion and infrastructure development from 1950 to 1979; special economic zone construction and rapid urbanization from 1980 to 2003; and Bay City construction since 2003. The dynamic changes to the coastline, island shape, built-up area, transportation, administrative division, and major land use type conversion which occurred during approximately the past 100 years were analyzed and the characteristics of the island urban spatial expansion were concluded： early expansion from a central point, followed by expansion along a section of coastline, and expansion from the coastline inland. Secondly, we discussed the potential determinants of island urban spatial expansion including administrative division adjustment, urban master planning revision, industrial development, topographical factors, coastal area reclamation, transportation expansion, and population growth. Finally, the effects of each potential determinant on island urban spatial expansion were concluded. Island urban spatial expansion is the result of a synthesis of natural and socio-economic factors which are not independent but interacting. Built-up area expansion is the major driver of island land cover and land use changes. By this paper, we hope to provide a scientific reference contributing to the rational understanding of island and coastal sustainable urbanization in China, and the world beyond.

Spatial expansion effects on urban ecosystem services supply-demand mismatching in Guanzhong Plain Urban Agglomeration of China

Global urbanization has led to drastic land use change,interfering the ecosystem services(ES)supply-demand balance,in turn threatening the well-being of humans.However,existing studies mainly stranded at the historical and current analysis,and the effects of urban spatial expansion on the relationship between ES supply and demand in the future are less clear,in particular at an urban agglomeration scale.This study was constructed with a framework of assessing the effects of urban spatial expansion on ES supply-demand mismatching under different future scenarios in the Guanzhong Plain Urban Agglomeration(GPUA)by using the Future Land Use Simulation(FLUS)model and expert-based Land-Use and Land-Cover Change(LUCC)matrix.The results showed that:(1)Urban expansion is significant in the natural development(ND)scenario,mainly manifesting the great transfer of dry land to construction land.(2)The gap between total ES supply and demand is narrowed from 2000 to 2030 and the mismatch between ES supply and demand is mainly reflected in the spatial distribution pattern in the GPUA.The ES budgets were in high surplus in Northern Qinling Mountains and northeast mountain areas,while they were in severe deficit in urban center areas.The budgets deficit under the ND scenario in 2030 is the most severe.(3)The gradient differences of ES budgets of the GPUA between urban centers and suburbs increase from 2000 to 2030 under two scenarios.The deficit region expands largest under ND scenario.The findings revealed that ES declining and supply-demand mismatching were triggered by the drastic land-use change driven by rapid urban expansion.The expansion has brought about an increasing material demand and growing industries,threatening the sustainability of ecosystems.Scenarios setting could contribute to coordinating the relationship between future urban development and ecological protection,and the policy strategies proposed in the study could inform ecological management and urban planning in the regions facing the similar urbanization situation.

Spatiotemporal Measurement of Regional Expansion in Changsha-Zhuzhou-Xiangtan Metropolitan Area Based on Nighttime Light Data

The research purpose is to accurately reveal the temporal and spatial law of the urban expansion of Changsha-Zhuzhou-Xiangtan, one of the seven major urban agglomeration areas in China, and provide decision-making basis for the future urban construction land layout and regional development policy-making. Based on the night lighting data (DMSP/OLS), this paper extracts the boundary of the urban construction land of Changsha-Zhuzhou-Xiangtan urban agglomeration from 1993 to 2017, and quantitatively studies the spatial and temporal characteristics of the expansion of the metropolitan area in the past 25 years according to the methods of spatial expansion analysis, center of gravity migration measurement, landscape pattern index, spatial autocorrelation, etc. The results show that: 1) it is scientific and feasible to extract urban agglomeration construction land by the method of auxiliary data comparison for the study of urban expansion;2) the expansion of regional space in Changsha-Zhuzhou-Xiangtan metropolitan area shows a trend of “weakening first and strengthening later”. The construction land keeps increasing, and the expansion form gradually changes from extensive type to intensive type;3) the center of gravity of the metropolitan area fluctuated and repeated in part during the past 25 years, but it was always located in the municipal district of Changsha city. The eastern region, mainly Changsha city, was still the core area of urban agglomeration expansion;4) strengthening the territorial space protection and control of ecological green core in the metropolitan area is a key measure for the high-quality development of urban agglomeration.

西部先发地区城市空间扩张特征及驱动因素探析——以陕西省为例

Compared with the stock-land exploitation of developed regions in eastern China,the development path in the western regions still relies on land expansion.Among them,Shaanxi stands out as an early-developing region with the highest comprehensive social and economic development level in the west,presenting a more significant and typical phenomenon of urban expansion.This paper utilizes remote sensing image data and socio-economic statistical data,employing mathematical and statistical analysis methods to examine the types and patterns of urban spatial expansion in Shaanxi over multiple years.It also summarizes the laws of expansion and subsequently delves into the driving factors of the spatial expansion.The result shows that the important driving factors of urban expansion in Shaanxi include natural geographical conditions,the economic development basis,the development of new towns and new areas,the drive of large-scale projects,and the guidance of urban and rural planning.The differences in driving factors between the east and west can be explained by the stages of regional development and the effects of administrative boundaries.This research aims to provide localized insights into the rational regulation of urban spatial evolution and efficient land use in similar regions and late-developing regions inwestern China.

基于城市流和层级性的城市群扩展模型构建

Since the launch of China’s reform and opening up policy,the process of urbanization in China has accelerated significantly.With the development of cities,inter-city interactions have become increasingly close,forming urban agglomerations that tend to be integrated.Urban agglomerations are regional spaces with network relationships and hierarchies,and have always been the main units for China to promote urbanization and regional coordinated development.In this paper,we comprehensively consider the network and hierarchical characteristics of an urban agglomeration,while using urban flow to describe the interactions of the inter-city networks and the hierarchical generalized linear model(HGLM)to reveal the hierarchical driving mechanism of the urban agglomeration.By coupling the HGLM with a cellular automata(CA)model,we introduced the HGLM-CA model for the simulation of the spatial expansion of an urban agglomeration,and compared the simulation results with those of the logistic-CA model and the biogeography-based optimization CA(BBO-CA)model.According to the results,we further analyzed the advantages and disadvantages of the proposed HGLM-CA model.We selected the middle reaches of the Yangtze River in China as the research area to conduct this empirical research,and simulated the spatial expansion of the urban agglomeration in 2017 on the basis of urban land-use data from 2007 and 2012.The results indicate that the spatial expansion of the urban agglomeration can be attributed to various driving factors.As a driving factor at the urban level,urban flow promotes the evolution of land use in the urban agglomeration,and also plays an important role in regulating cell-level factors,making the cell-level factors of different cities show different driving effects.The HGLM-CA model is able to obtain a higher simulation accuracy than the logistic-CA model,which indicates that the simulation results for urban agglomeration expansion considering urban flow and hierarchical characteristics are more accurate.When compared with the intelligent algorithm model,i.e.,BBO-CA,the HGLM-CA model obtains a lower simulation accuracy,but it can analyze the interaction of the various driving factors from a hierarchical perspective.It also has a strong explanatory effect for the spatial expansion mechanism of urban agglomerations.