Research On The Application Of The Integrated Landscape Index In The Simulation Of Urban Growth Boundary

2020 is the closing year of China's 13 th five year plan,and it is also an important period of China's industrialization and urbanization transformation.Ecological environment protection and land resource utilization will face huge challenges.How to balance economic development and ecological environment has become a prominent contradiction that must be solved.In the nineteen major reports,general secretary Xi Jinping proposed to speed up the reform of the ecological civilization system and build a beautiful China.This idea is not only the latest achievement of Sinicization of Marxism,but also the only way for China's future development.Among them,it is of great significance to realize the sustainable development of the city to manage the urban land problem,guide the orderly and reasonable expansion of urban construction land,and improve the efficiency of land use;at the same time,it is necessary to take into account the ecological environment,avoid the damage of urban expansion,keep the cultivated land area from being encroached,and improve the food security system.As an effective method to balance urban expansion with ecological protection and cultivated land protection,urban growth boundary has been widely used in the study of urban expansion.Based on the land use data of Nanning city from 1995 to 2015,this paper uses the land use transfer matrix to analyze the spatiotemporal change law of land use in the study area in the past 20 years.Secondly,the landscape pattern of the study area is further analyzed from the perspective of landscape ecology,and then combined with digital elevation model and point of interest(POI)Based on the data of traffic network,population density distribution,GDP distribution and so on,the paper constructs the flu model composed of neural network and cellular automata,delimits the urban growth boundary of the main urban area of Nanning,and provides reference theory for urban planning and land management.The main conclusions are as follows(1)In the past 20 years,the expansion of urban construction land in Nanning city is mainly in the East and Southeast,and the new construction land is mainly cultivated land,accounting for 66% of the total new area,followed by woodland and grassland.From 2010 to 2015,the increase of the new area is the largest,reaching40%.The new ways include external expansion and internal filling.The area of cultivated land,forest land and grassland decreased to a certain extent.The area change of water body and unused land is not obvious.(2)This paper analyzes the landscape pattern characteristics of the study area from the perspective of landscape science,and selects five landscape index indexes from the two scales of landscape type and landscape as a whole to further study the complexity and richness of the landscape structure,the shape characteristics and distribution density of landscape patches.The results show that the urban expansion of Nanning city is inadequate and incomplete,the jumping development of new construction land is less,and the extension development is more important;human social and economic activities have a great impact on the landscape pattern,and the ecological environment has been damaged to a certain extent.(3)The landscape comprehensive index of patch scale is based on the binary logic regression analysis and correlation analysis,and the landscape index type suitable for the study of urban growth boundary is selected,and the comprehensive landscape index is calculated.The value is grid spatialized and combined with the FLUS model,Improve the result accuracy of the model.(4)Based on the land use data of 2010,this paper selects 20 factors,such as terrain,population distribution,GDP and the distance to each important geographical element,and obtains the probability data of land adaptability through Ann module training;through the parameter setting of CA module,combined with the probability data of land adaptability,simulates the land use distribution in 2015,and compares it with the real land use data in 2015 Kappa coefficient based on confusion matrix is used to verify the reliability of the model.The results show that the accuracy of the model is 0.770679,and the numerical value is high,which indicates that the model meets the accuracy requirements.By adding comprehensive landscape index to the original model,the edge of the patch is smoother,the kappa coefficient is 0.796113,and the accuracy is improved by 3.3%.(5)Based on the concept of ecological civilization,four factors including terrain,cultivated land protection,ecological protection and disaster prone were selected to delimit the rigid growth boundary of Nanning City,accounting for 42.5% of the study area.Finally,the land use elasticity of Nanning in 2006-2020 is simulated,and the land use elasticity of Nanning in 2006-2020 is predicted.