Abstract: Yangzhou City, which lies besides the north bank of the Yangtze River, was built in B.C. 486. Within 2500 years, it experienced great developments and changes in several important historical periods (Spring and Autumn, Han Dynasty, Jin Dynasty, Tang Dynasty, Song Dynasty, Ming and Qing Dynasties). Based on literature of historical geography and archaeological data, using the historical geography method and 3S (GIS, RS and GPS), this study integrated estuary change, river bank change and canal change with urban change of Yangzhou City. Firstly, the boundary of the Yangzhou City was made on the images in Sept. 2006 of the LANDSAT ETM remote sensing data based on its administrative map; then according to history literature and archaeology data, key points for the boundary of the Yangzhou City were selected and located by GPS field observation and stacked with the RS image, using ArcGIS9.3 to simulate the change process of the Yangtze River in different periods and acquire its attribute data quantitatively, based on which, characteristics of urban change were analyzed in six historical periods and the driving factors for the urban change were discussed. The results show that climate change was the background of urban changes of the Yangzhou City, but these changes were also affected by several other factors. The changes of the Yangtze River channel and the Hangou Canal guided the changes of the Yangzhou City. The spatial changes of the bank of the Yangtze River and of the Hangou Canal in different periods were estimated. The silted area and water area of the Yangtze River within Yangzhou City in historical periods were calculated. The changes that took place in the ancient Yangzhou City were caused by the silt of the Yangtze River moving the bank southward by deposition on its northern bank, which in turn resulted in the necessary extension of the Canal for shipping. The city extended its area, following the extension of the Canal. Even when the city decreased in size, it did so by retreating back towards the Canal. In general, before the Tang Dynasty, the city was changed mainly by natural factors and after the Tang Dynasty by human factors.

Key words: Yangzhou City, urban change, 3S, spatial distribution, sedimentation

摘要： 基于考古学及历史地理学的研究成果, 运用3S技术和历史地理学方法, 将河口变迁、河道变迁、运河变迁与城市空间演变相结合, 探讨古城扬州在2500年间城市空间演变的驱动力因素。首先基于行政区划图在2006年LANDSAT ETM遥感影像图上截取扬州市区边界; 然后以历史文献及考古资料为基础, 对关键点进行GPS定位, 利用ArcGIS9.3将位置点和影像数据叠加, 复原历史时期扬州附近长江河道的演变过程, 定量获取古城扬州在不同时期的属性数据, 由长江河道与邗沟的演变过程, 得到不同历史时期扬州城的水域面积、泥沙淤积面积及城市面积; 最后, 依据属性数据分析扬州城市演化的特征, 并探讨影响古城扬州空间演变的驱动力因素。结果表明: 扬州城市演变是多种因素作用的结果, 其中气候因素是城市演变的大背景; 长江河道和运河水系变化则引导城市演化的方向; 长江河道北岸由于大量泥沙淤积南移导致古城扬州的演变, 反过来又带动内河航运的延伸, 城市则依运河的方向拓展, 即使城市缩小了, 依然邻近运河的方向; 总体上看, 唐代之前, 城市演变受自然因素影响较多, 唐代之后则受人文因素影响较多。

关键词: 扬州, 城市演变, 3S, 空间分布, 泥沙淤积