南通地区城镇用地扩展时空特征分析

以多时相LandsatTM/ETM卫星遥感影像为数据源,引入扩展速度、扩展强度、分维数、空间自相关指数等测度指标,分析了南通地区各类城镇的用地扩展过程、形态变化、结构分异及空间格局等时空特征。结果表明:①各类城镇用地扩展速度逐渐提高,扩展强度逐渐加大;②区域城镇用地扩展在1980年代以中心城市扩展为主,1990年代以后则以县(市)城和建制镇用地扩展为主;③因区域城市化进程加速和自然条件的影响,城镇用地分维数呈现逐渐增大的趋势,表明城镇用地的形态越来越不稳定;④城镇用地扩展主要以中、低速扩展类型为主;⑤城镇用地扩展速度、扩展强度的空间自相关性偏弱,但个别类型也呈现出集聚分布的趋势,如扩展速度的高值区域呈现出一定的临江和沿交通干线分布的特征,扩展强度的高值区围绕中心城市分布。

Spatio-temporal Characteristics of Urbanization Area Growth in Nantong City, Jiangsu Province

The spatio-temporal characteristis of urbanization area are important indices to evaluate and/or show the regional social and economic development.Nantong,a medium sized city affiliated to Jiangsu province,is located in north of the Yangtze Delta with developed economy in China and alongside the Yangtze River,whose opposite is Shanghai.Based on the Landsat TM/ETM satellite images acquired in 1984,1991,1997,2000 and 2003,as well as information extracted on urbanization areas including urban area,town area and county seat area with the help of GIS,we analyzed in details the spatio-temporal characteristics including urban expansion process,morphologic change,structure differentiation of growth speed using some indices such as growth speed,growth intensity,fractal dimension,spatial autocorrelation index and so on.Additionally,the characteristic of spatial pattern was also analyzed on the basis of the above-mentioned iodices.The result shows:(1)the growth speeds of all kinds of urbanization area are accelerated,and the growth intensities enhanced gradually from 1984 to 2003;(2)in the 1980s,the growth of urbanization areas was dominated by central city expansion,but since the 1990s by county(city) seat and the administrative towns;(3)the fractal dimensions of urban land use inc-reased gradually,which indicates that the town growth is unsteady,attributed to the acceleration of regional urbanization process and limitations of natural conditions;(4)the types of urban land growth are mainly centralized on the middle and lower speed of expansion;and(5) the spatial au-tocorrelation characteristics of urbanization area growth speed and intensity are not evident.But some individual type presents the cluster distribution tendency to some degree.For example,the high value regions of urbanization area growth speed are distributed along the Yangtze River and along some main communication lines.Whereas the high value regions of expansion intensities are distributed around the central city.