Exploring Smart Growth Boundaries of Urban Agglomeration with Land Use Spatial Optimization: A Case Study of Changsha-Zhuzhou-Xiangtan City Group, China

2020 ◽  
Vol 30 (4) ◽  
pp. 665-676
Author(s):  
Shifa Ma ◽  
Yabo Zhao ◽  
Xiaohong Tan
2020 ◽  
Author(s):  
Yinglu Liu

<p>Contradictions between population, economic development, land and ecological environment occur frequently in the Beijing-Tianjin-Hebei urban agglomeration, forming a complex problem of "population - land - social economy - ecological environment" at a regional level. This study considers seven indicators, including LUCC and three typical ecosystem services, to recognize the critical regions. Through continuous experiments and adjustments of parameters, we finally determine the building methods of overlaying in a equal power, and quantificationally evaluate the land use dynamic degrees, land use extents, diversity of land use types, ecological land use ratio, carbon sequestration service, soil conservation and water production services, integrated identify critical areas of the Beijing-Tianjin-Hebei urban agglomeration. We aim at realizing the coordinated sustainable development of Beijing-Tianjin-Hebei region as soon as possible, and providing the basis for land planning. The results show that the critical regions of the Beijing-Tianjin-Hebei urban agglomeration are mainly distributed in the Yanshan and Taihang mountain regions and the surrounding towns. On the scale of county level, the first-level critical regions are mainly located in Beijing, Qinhuangdao and Chengde, and the second-level critical regions are mainly located in Chengde, Beijing, Qinhuangdao and Baoding.</p>


Author(s):  
Fengjian Ge ◽  
Guiling Tang ◽  
Mingxing Zhong ◽  
Yi Zhang ◽  
Jia Xiao ◽  
...  

Urban agglomerations have gradually formed in different Chinese cities, exerting great pressure on the ecological environment. Ecosystem health is an important index for the evaluation of the sustainable development of cities, but it has rarely been used for urban agglomerations. In this study, the ecosystem health in the middle reaches of the Yangtze River Urban Agglomeration was assessed using the ecosystem vigor, organization, resilience, and services framework at the county scale. A GeoDetector was used to determine the effects of seven factors on ecosystem health. The results show that: (1) The spatial distribution of ecosystem health differs significantly. The ecosystem health in the centers of Wuhan Metropolis, Changsha–Zhuzhou–Xiangtan City Group, and Poyang Lake City Group is significantly lower than in surrounding areas. (2) Temporally, well-level research units improve gradually; research units with relatively weak levels remain relatively stable. (3) The land use degree is the main factor affecting ecosystem health, with interactions between the different factors. The effects of these factors on ecosystem health are enhanced or nonlinear; (4) The effect of the proportion of construction land on ecosystem health increases over time. The layout used in urban land use planning significantly affects ecosystem health.


Author(s):  
Renyang Wang ◽  
Qingsong He ◽  
Lu Zhang ◽  
Huiying Wang

Enhancing urban vitality is a key goal for both the government and ordinary urban residents, and creating this vitality is emphasized in China’s urban development strategy. Enhancing urban vitality through the rational design of urban forms is a leading topic of Western urban research. An urban growth pattern (UGP) reflects the dual characteristics of a static pattern and the dynamic evolution of the external urban form. It affects urban vitality by influencing the spatial allocation of internal structural elements and patterns in the adjacent location. The cellular automata (CA) mode can effectively simulate the aggregation process of urban growth (infilling expansion or edge expansion). However, it does not simulate the diffusion of urban growth, specifically the evolution of outlying expansion. In addition, CA focuses on learning, simulating, and building knowledge about geographic processes, but does not spatially optimize collaborative land use against multiple objectives or model multi-scale land use. As such, this paper applies a coupling model called the “promoting urban vitality model,” based on cellular automata (CA) and genetic algorithm (GA) (abbreviated as UV-CAGA). UV-CAGA optimally allocates cells with different UGPs, creating a city form that promotes urban vitality. Wuhan, the largest city in Central China, was selected as a case study to simulate and optimize its urban morphology for 2025. The main findings were as follows. (1) The urban vitality of the optimized urban form scheme was 4.8% higher than the simulated natural expansion scheme. (2) Compared to 2015, after optimization, the simulated sizes of the newly increased outlying, edge, and infilling areas in 2025 were 6.51 km2, 102.69 km2, and 23.48 km2, respectively; these increases accounted for 4.90%, 77.32%, and 17.68%, respectively, of the newly increased construction land area. This indicated that Wuhan is expected to have a very compact urban form. (3) The infilling expansion type resulted in the highest average urban vitality level (0.215); the edge expansion type had the second highest level (0.206); outlying growth achieved the lowest vitality level (0.199). The UV-CAGA model proposed in this paper improves on existing geographical process simulation and spatial optimization models. The study successfully couples the “bottom-up” CA model and “top-down” genetic algorithm to generate dynamic urban form optimization simulations. This significantly improves upon traditional CA models, which do not simulate the “diffusion” process. At the same time, the spatial optimization framework of the genetic algorithm in the model also provides insights related to other effects related to urban form optimization, such as urban environmental security, commuting, and air pollution. The integration of related research is expected to enrich and improve urban planning tools and improve the topic’s scientific foundation.


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