基于Landsat的合肥市城市扩张研究

Study on urban expansion of Hefei city based on Landsat data

城市扩张及其驱动力分析在协调城市扩张与土地资源保护的矛盾、促进城市可持续发展中具有重要作用.以合肥市1996,1999,2002,2005,2008,2011,2014年Landsat影像为数据源,采用监督分类方法获取合肥市城市用地时空分布定量信息,从城市面积变化、形态变化和重心迁移3个方面分析合肥市城市扩张情况,并结合自然环境、经济发展、人口增长、交通建设、政府行为等影响因子对合肥市城市发展的驱动力进行分析.结果表明:1996～2014年合肥市城市用地面积扩张286.09km^2,扩张率为394.7%,扩张速度为15.89km^2·a^(-1).近20a来,合肥市在外形上逐渐趋于狭长,以向西南扩张为主,并呈现以交通线为主的星形扩张,城区扩张亦十分明显.驱动力分析得出合肥市扩张的主要影响因子为人口增长与经济发展.

Analysis on urban expansion and its potential drivers play an important role in coordinating the contradiction between urban expansion and land resources protection and in promoting the urban sustainable development.Based on the series of Landsat images in 1996,1999,2002,2005,2008,2011 and 2014,we extracted the spatiotemporal distribution of city information of Hefei using supervised classification method.The urban expansion of Hefei city were analyzed from three aspects,urban area change,shape change and center of gravity.Furthermore,the natural environment,economic development,population growth,traffic construction,government behavior and other factors were combined to investigate the driving forces of urban development in Hefei city.The results show that:From 1996 to 2014,the urban land area of Hefei is 286.09 km^2;The expansion rate is 394.7%;And the expansion velocity is 15.89 km^2·a^(-1).The appearance of urban expansion is very obvious.Specifically speaking,during the past nearly 20 a,the expansion appearance of Hefei city gradually tends to be narrow with the expansion direction towards the southwest;And,the expansion pattern appears as the star expansion mainly by transportation routes.The driving force analyses show that the main influencing factors of Hefei expansion are population growth and economic development.