城市空间扩散增长模型与模拟

A SPATIAL SPRAWL AND GROWTH MODEL OF THE CITY AND SIMULATION

城市模型模拟是上世纪 90年代上半期形成并迅速发展的地学计算理论、方法与应用研究的最重要领域 ,国外以M .Batty为代表的规划与地理学家们进行了开创性的研究 ,取得了很多有用成果。本文借鉴这些学者的研究思路 ,从城市土地利用与开发的视角 ,利用疾病感染、传播机理的模拟方法 ,研究城市空间扩展、演化动力学过程的模型模拟问题 ;为模拟城市土地开发利用在不同阶段的表现与特征 ,研究了基本模型的不同变换形式 ;讨论了基于细胞自动机模型的城市空间扩展模型的计算结构 ,依据模拟结果 ,探讨了以城市形态扩展特征为指标进行城市分类的可行性 。

Study on the citys evolving model and its simulation is one of the most important fields of research on the theory, and methodology and applications of geocomputation founded and developed in the 1990s. In this paper, from a view of land use and development in a city, land in a city can be divided into three patterns of developed, new developing and applicable areas, and a full dynamic process of the citys sprawl and expansion can be simplified and described as a developing spectrogram consisted of growing to decreasing to newly developing from a seed, i. e. CBD of a city to its boundary areas. Based on the idea and modeling method of the infected and spread mechanism of the epidemic, a spatial sprawl and growth model of citys development is established and put forward, a dynamic process described the citys spatial evolving is simulated and studied in the paper. In order to simulate and analyze the features of land use and development in different developing stages in a city, a lot of transformation patterns of the foundational model under some supposed conditions, which is applicable to a few real cities, is discussed. A computational framework for the spatial sprawl and growth model based on cellular automata is introduced and discussed. After a discussion and analysis on the modeling and simulating results, a possible useful citys classification system making use the citys expansion features as main indicators have been put forward in the last section of the paper. These indicators include the growth rate of land use and development, the average time length of land development in practice and vacant rate of land used for the development in the end of the sprawl and growth process. The main purpose of the paper is to expand and develop the research and modeling methodology of the urban geography so as to offer the basis of prediction and controlling of urban development. Thus the development of geo computation theory and methodology could take the research on urban modeling to a higher level.