Research On Demarcation Of Urban Development Boundary In The Eastern River Valley Of Lixian County In Combination With Ecological Security Patterns

Since the beginning of the 21st century,the vigorous development of high-tech science and technology in the United States and the rapid advancement of China’s urbanization process have greatly changed the pace and appearance of world development^[1].After the reform and opening up,my country’s rapid economic development has accelerated the pace of urbanization,resulting in the rapid outward expansion of urban space.The advancement of this process has encroached on a large number of important ecological land such as arable land,and extensive land use not only wastes land resources,but also makes the amount of land for construction has dropped sharply,putting tremendous pressure on the ecological environment and resources.As a policy measure to limit the spread and guide the rational development of cities and towns,the development boundary of cities and towns has not only attracted much attention at the national level,but has also been studied and practiced for many years in academia.For the delineation of urban development boundaries,a series of guidance documents have been issued at the national level,forming a set of relatively unified procedures and norms.However,due to the large differences between different regions,the evaluation method has a certain degree of flexibility.In the past,the delineation of urban growth boundaries and urban development boundaries was mainly aimed at large cities that developed too quickly.They were delineated in order to control the size of their central urban areas,and less attention was paid to county-level or even smaller areas.On the basis of understanding that urban development boundaries are guiding the rational development of urban space,this paper selects seven towns in Li County that are easy to urbanize to form a closed administrative area,and regards them as the research object of this paper,considering the impact of land and space planning on resource endowment and ecological environment.It attaches great importance to it and chooses to explore and practice the path delineation of urban development boundaries by constructing a comprehensive ecological security bureau and coupling urban spatial expansion.The content of the six chapters of this article will be expanded from the following three parts.Firstly,will do the basic research in which the thesis where is the first and second chapters.This part elaborates on the research background,research purpose and research significance of the paper based on the reading and collation of related literature,as well as building a model and operation which can delimiting the urban development boundary of Lixain County.At the same time,this research involves The related concepts（ecological security pattern,urban development boundary）and theories（sustainable development theory,smart growth theory,"anti-planning"theory）of the company gave detailed explanations and explanations.On the premise of reading the literature extensively,the domestic and foreign Summarize and evaluate the research progress of urban development boundaries and their delineation methods.Secondly,will build the model about this research,which is the third chapter in the thesis.This part builds a model for the delineation of the urban development boundary of Lixian County under the constraints of ecological security,and the boundary of urban development is divided into two parts.First,the bottom line area that cannot be broken through urban development and construction is delineated,namely Urban rigid development boundary.In addition,combined with urban development intentions and goals in a certain period of time,delineate flexible development areas with dynamic guidance,that is,urban flexible development boundaries;and establish appropriate model methods for the two delineation and select the corresponding Indicators;specific methods and models used to delimit rigid and flexible development boundaries:principal component analysis,K-means cluster analysis,and minimum cumulative resistance model are explained in detail.Finally,the research on the delimitation of the development boundary,which is chapter4 and chapter 5 in the thesis.This part first analyzes the expansion of construction land in the past 20 years through remote sensing image interpretation,analyzes the area change of different land types combined with the land use transfer matrix,and summarizes the dynamic mechanism of urban spatial expansion in Li County;combined with the delineation model constructed in the previous article,The rigid development boundary can provide 9603.56 hectares of construction land.The flexible development boundary is obtained through the minimum cumulative resistance model combined with the prediction of the population and construction land scale in the overall plan in 2030,and is compared with the urban development control area in the overall plan.By comparison,it is found that the two are highly consistent in form and expansion trend,but due to different starting points,there will be some discrepancies in the framing and selection of key construction areas.