开封市城市扩张动态监测及驱动因子分析

Dynamic monitoring and driving factors analysis of urban expansion in Kaifeng

近年来随着城市化进程的不断加深,城市扩张问题日益突出,土地资源浪费及生态环境污染问题也随之而来。采用支持向量机监督分类方法和人机交互解译方式对开封市土地利用进行分类,提取城市建成区范围,采用扩张速度指数(expansion speed index,ESI)、扩张强度指数(expansion intensity index,EII)、平均中心(mean centre,MC)和标准差椭圆(standard deviational ellipse,SDE)等指标分析开封市1990—2015年25 a间的城市建设用地扩张及其空间分布,并基于社会统计数据对城市扩张驱动因子进行分析。结果表明,开封市区建设用地呈扩张趋势,由1990年的38. 08 km2增加到2015年的125. 86 km2,扩张速度达3. 51 km2/a; MC和SDE分析得出,25 a间开封市城市平均中心位置变化不大,整体向西北方向移动; 1990—2009年建成区空间扩张呈均衡化; 2009—2015年建成区持续西扩,空间分布存在明显方向性;利用SPSS软件对社会统计数据进行分析得出,城市人口数量及经济发展等是开封市城市扩张的主要驱动力。

With the deepening of urbanization,the problem of urban expansion has become more and more prominent,and the problem of land resource waste and eco-environment pollution has also occurred with urban expansion. Based on the support vector machine(SVM) classification method and the way of man-computer interactive interpretation,the authors classified the land of Kaifeng and extracted the city proper,analyzed the urban construction land expansion and spatial distribution in the past 25 years by using the indexes such as expansion speed index(ESI),expansion intensity index(EII),mean center(MC) and standard deviational ellipse(SDE),and analyzed the drive factor of urban expansion based on the social statistics. The results reveal that,firstly,the urban construction land of Kaifeng expands from 38. 08 km2 in 1990 to 125. 86 km2 in 2015,with the expansion speed reaching 3. 51 km2/a. Secondly,MC and SDE show that the average central position of Kaifeng City has changed a little in the past 25 years,it has moved northwest entirety,and the spatial distribution of construction land tended to expand evenly from 1990 to 2009,the construction area continued to expand and the spatial distribution was directional obviously from 2009 to 2015. Finally,it is concluded that the quantity of urban population and the economic development are the main driving forces of urban expansion in Kaifeng City.