城市化是区域人口增长与社会经济发展的综合进程,其最为明显的特征是城市空间扩张.研究采用面向对象最近邻分类以及概率神经网络分类的方法,从Landsat TM影像中提取我国东(广州)、中(合肥)、西部(西宁)城市主城区建设用地信息,应用皮尔逊卡方检验、香农熵模型以及城市扩张速度等计算3个城市相同时间段内的城市扩张自由度、蔓延度、感观优劣度等,对研究区1995-2010年期间的扩张特征进行时空综合度量.结果表明:1)不同城市扩张特征不尽相同,东(广州)、中部(合肥)城市相较西部(西宁)扩张自由度及蔓延度偏高,区域差异明显;2)东(广州)、中部(合肥)城市扩张感观优劣度相对较低,应努力构建并完善城市扩张监管体系,统筹协调城市建设用地的开发利用,积极推进高质量城镇化,实现城市的可持续发展;3)东(广州)、中部(合肥)相较西部(西宁)近15年扩张明显,扩张速度较快.%Urbanization is a comprehensive process of regional population growth and socio-economic development, the most obvious feature is the expansion of urban space.The research uses object-oriented nearest neighbor classification and probabilistic neural network classification method to extract main city construction use land information of east China (Guangzhou), middle China (Hefei), and west China (Xining), and from Landsat TM images, applications pierxunka square test, Shannon entropy models and urban sprawl dynamic degree to calculate the degree of freedom, the degree of spread and the degree of sensory quality of three cities of the same period, has a comprehensive measure of expansion characteristics in the research area from 1995 to 2010.The results showed that: (1) Urban sprawl characteristics are different in different countries , east China (Guangzhou) and middle China (Hefei), which are compared to west China (Xining) are high in expansion, the degree of freedom and the degree of spread , the regional differences are significant.(2) East China (Guangzhou) and middle China (Hefei) are low in the expansion degree of sensory quality compared to west China (Xining).We should make efforts to build and improve the urban expansion regulatory, coordinate the development and utilization of urban construction land comprehensively, and promote high quality urbanization actively, realize sustainable development.(3) East China (Guangzhou) and middle China (Hefei) sprawl obviouly in the past 15 years compared to west China (Xining), is faster in expansion speed.
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