Scenario Simulation Of Construction Land Expansion In Central District Of Guangfeng District Of Shangrao Based On SLEUTH Model

Small-medium cities are the important strategic nodes in the administrative system of our country,and the main battlefield of our future urbanization construction.However,due to the high per capita land use index,unreasonable land use spatial structure,non-centralized and compact land use and other unreasonable phenomena caused by the phases of the development of Small-medium cities,government intervention,natural environment conditions and other factors.The adjustment of urban development policy in the future needs to pay attention to the impact of different urban spatial development policies on the expansion of construction land.Therefore,taking Guang feng District,Shang rao City,a semi-hilly and semi-mountainous area in the northern foot of Wu yi Mountains as an example,this paper analyzes the characteristics of construction land expansion,sets up three different scenarios of construction land expansion,simulates the spatial pattern of construction land in the next 12 years under three scenarios using SLEUTH model,and adopts the methods of standard deviation ellipse and landscape pattern index.(1)The spatial and temporal characteristics of construction land expansion and the change characteristics of expansion mode in Guang feng District between 2000 and 2017 were analyzed by means of expansion intensity,equal sector analysis and public edge measurement.The results show that:in the past 17 years,the construction land area continues to increase,and the expansion intensity gradually strengthens;the construction land expansion shows different spatial differentiation characteristics in different periods,mainly in the southwest direction in 2000-2011,the southern expansion slowed down by terrain constraints in 2011-2017,and the northern expansion began to accelerate.The expansion of construction land in Guang feng City has undergone four stages of "scattered spread-axis spread-interior fill-scattered spread",which is essentially a process of single-center urban area from point to surface and gradually spread.Population growth,economic development,urban transportation,urban development space policy and natural ecological conditions play an important role in the expansion of construction land.(2)SLEUTH model is used to simulate the spatial pattern of construction land expansion in Guang feng District in the next 12 years.The results show that the area index and shape index of the calibration stage model are similar to those of the similar research,and the model has better fitting ability;the Kappa coefficients of the simulation results are all greater than 0.69,which is equivalent to other successful application cases in China.The accuracy of the model simulation is up to the requirements.The SLEUTH model is applicable to the simulation of construction land expansion in Central District of Guang feng.The spatial pattern of construction land in Guang feng downtown area in the future under the three scenarios has both similarities and significant differences.The scale of construction land expansion under the ecological constraint scenario can not satisfied the requirement of city development.And city development in accordance with current trends scenario is the most decentralized.The planning guidance scenario because of the compact construction land,affected by the landscape pattern,the construction land integration is less;the number of patches is large.(3)According to the scenario simulation results,combined with the analysis of the expansion of construction land,the development proposals are put forward.The northern part of the city is the main area for future urban development,and the construction land should expand northward.The urban area is suitable for the development of dual-center spatial structure,and the green space between new and old urban areas should be strictly protected,and the expansion of construction land in this area should be strictly controlled.Under the dual center urban spatial development structure,it is suggested to build a city pattern on one side of the river with one main and three sub zones.The Weng Ling Xi Tan and the lower stream areas in the northern part of the city should be extended to the west to strengthen the lateral axis.