Study On Urban 3D Spatial Expansion And Dynamic Simulation Based On CA/MAS

With the acceleration of urbanization,the expansion of urban space is facing numerous complex problems.In order to meet the rapid development of urbanization and the everincreasing demand,the city is showing an increasingly strong three-dimensional trend.Under the background of increasing urban volume,the spatial form of the urban structure in the horizontal direction can no longer satisfy the needs of research.From a three-dimensional perspective,studying urban morphology,grasping the law of urban spatial expansion,and enriching the theory of urban expansion has become more important.This paper takes the threedimensional urban space as the research object,constructs the index system to describe the evolution of three-dimensional urban spatial form,and explores the objective law and dynamic factors of three-dimensional urban expansion.And this paper uses CA and MAS model to simulate the expansion of urban three-dimensional space in the main city of Dalian as an example,in order to provide some reference for the expansion of urban space research to highdimensional.The main conclusions of the paper are:(1)Urban land use classification and data of buildings are interpreted,through the combined use of open data on the Internet,high-resolution remote sensing images,and stereoscopic data.It can provide more data sources for future scientific research.(2)3D normalized compactness index is constructed,and the expansion of threedimensional space in the main urban area of Dalian is measured by combining the weighted average height,volume of buildings and the 3D spatial expansion strength index.And its main features are:From 2012 to 2016,all building types showed a remarkable three-dimensional expansion trend,among which commercial buildings are mainly expanded to high-rise buildings,industrial buildings are mainly expanded to the periphery,and the number of residential buildings has a relatively high growth;The areas with higher 3D compactness are axially extended and clustered;The areas of higher 3D spatial expansion strength index are mainly in the north of Zhongshan District,the east and west of the Shahekou District;The regions with lower index are mainly concentrated in the central part of Xigang District and so on.(3)The three-dimensional spatial expansion of the main urban area are simulated with the coupling of CA based on constrained logistic regression and housing demand model of MAS.The CA layer determines the location of the city's two-dimensional expansion and the Agent layer calculates the heights of the buildings.The accuracy of the simulation is verified by comparing density and volume of buildings in the same block between the simulation results and the actual results.And it is considered that the model has a good fitting effect.Based on this,the expansion of urban three-dimensional space is forecasted in 2020.