Research On Urban Growth Boundary Of Guangzhou Under Bi-directional Path

With the rapid development of industrialization and urbanization,the rapid expansion of urban space is a serious threat to national food security,farmland protection and ecological environment.At the same time,the disorderly expansion of construction land causes the urban spatial structure to be loose,serious land idle or waste,and low land use efficiency.The emergence of these problems requires that urban growth mode transforms to the mode of combination of extension and connotation development,to the mode of combination of construction development needs and ecological protection,in order to achieve sustainable urban development.As one of the most effective methods of urban growth management,urban growth boundary plays an important role in coordinating the protection and the development needs.After research and analyze the existing problems of urban growth boundary,this paper tries to use the concept of bi-directional path planning,considers the combination of urban growth and ecological constraints,and constructs the theoretical framework of urban growth boundary delimitation,takes Guangzhou as a typical case to put forward the specific method,in order to improve the theoretical system and the technical methods of urban growth boundary.Based on Arc GIS platform as technical support,taking Guangzhou as the empirical research object,this paper focuses on the research of urban growth boundary of Guangzhou under the bi-directional path on the basis of the analysis of urban spatial expansion of Guangzhou,results show:(1)There were obvious characteristics of circle type expansion which mainly presented the expansion from center to periphery in urban spatial expansion in Guangzhou during each period.In different periods,the expanding active center was gradually pushed outward from center to periphery at a certain time sequence and highly active in quadrants of north-north,north-east,east-east,and south-east.(2)Among the numerous influential factors,natural environment is the basic limiting factor for construction land expansion,socio-economy is the main driving factor for construction land expansion,traffic has a specific guiding role in construction land expansion,and macro control determines the direction and intensity of construction land expansion in a certain period.(3)The urban growth boundary of Guangzhou under bi-directional path which meet the future demand for city construction and development can effectively curb the spread and occupation of construction land to the highly sensitive areas and maximize the protection of ecological land and the maintenance of ecosystem structure.(4)Compared with "forward planning" and "reverse planning",both the method system and the specific method of demarcation show that the urban growth boundary delimitation under bi-directional path is more advanced and feasible.But compared with the planning practice of Guangzhou,urban growth boundary delineated in this paper is consistent in the general direction,but there are still some differences in individual areas.As a whole,this result is more precise and more valuable.