Simulation Of Urban Spatial Expansion Of Yinchuan Plain Based On Multi-Agent Model

The town is a complex system,and its birth and evolution are influenced by various factors such as politics,economy,culture and population.Urban expansion is the dominant process of regional land use change.Rapid urbanization can bring a series of problems to the society,including extensive use of land resources,duplication of functional structure,low land use intensification,etc.Currently,the study of characteristics land use changes has become one of the important contents of urban system research,which is in order to achieve urban growth management and land resource protection.The expansion of urban space is mainly the result of continuous interaction between humans and the environment.The multi-agent model can not only realize the objective description and expression of human individual behavior through the agents with the abilities of cognition,learning,feedback and autonomous behavior,but can also simulate land use pattern evolution through the“bottom-up” modeling approach,so the problems in urban spatial expansion research can be better solved.This paper selected Yinchuan Plain as the research area,used 3S technologies,statistical method and multi-agent modeling as means to reconstruct the urban spatial expansion process in Yinchuan Plain.Three scenarios were set up for prediction 2025 and 2030 urban expansion to support policy-making in urban planning.The main contents of the paper are as follows:Firstly,the urban landscape pattern and urban expansion driving forces of Yinchuan Plain in 1989-2018 are analyzed,and the conditions and factors affecting the urban expansion process in the study area are confirmed.The urban area of Yinchuan Plain increased continuously from 1989 to 2018,the main source of the increase was the conversion of agricultural land,unused land and green space;the overall heterogeneity of the landscape pattern in the study area was low but the landscape fragmentation as well as the dispersity has increased;the driving forces affecting urban expansion are mainly based on population growth,economicdevelopment,government investment,and industrial structure changes.Secondly,the agents are confirmed then the multi-agent decision-making behavior rules are formulated.The internal contact and mutual feedback mechanism between the agent system and the environment system are analyzed.The Netlogo software platform is used to build,run and debug the model,and the simulation results of 2018 are tested to analyze the source of error.The results of 2018 land use simulation of multi-agent urban spatial expansion model have good fitness with remote sensing image interpretation.The overall simulation accuracy is 84.06%.Errors are caused by loss of information in data processing and limitations of agents behavior.Thirdly,the expansion pattern of the urban space of Yinchuan Plain in 2025 and2030 are predicted based on the metropolitan development scenario,small city group development scenario and farmland protection scenario.Based on three scenarios setting,the urban expansion trend in 2025 and 2030 are predicted.In the metropolitan development scenario,the study area showed an expansion trend with Yinchuan City as its focus in general.In small city group development scenario,the southern Litong District,Qingtongxia City and Lingwu City gradually expanded and connected.In the scenario of farmland protection,the urban expansion is slower than the other scenarios,and the villages are reduced and concentrated.And the three predict results are compared comprehensively.Finally,combined with the three predicted results and current policies,reasonable planning suggestions are given as follows: Firstly,give priority to the development of Yinchuan city with complementary of the development of the small towns belts on the south and north of Yinchuan.Secondly,implement differentiated control measures,give priority to the development of unused land,calculate and reduce unreasonable resource occupation.Thirdly,build farmland protection system,construct peasant residential communities,and promote intensive development of towns and villages.