分形与元胞自动机耦合技术应用于厦门城市生态规划

Application of Fractal Technology and CA in Xiamen Urban Ecology Planning

利用2002、2007年的两期TM影像数据,基于分形方法研究了厦门的城市形态特征。首先,利用网格计数分维法得出,自2002年以来分形维数从1.804增至2007年的1.847。由于其分形维数1.847已经超越了城市理想形态维数(1.71±0.02)。结合城市形态发展规律,今后厦门岛的分形维数递增速率减缓后会逐渐回归到城市理想形态维数值。其次,通过集聚分形方法确定了以厦门市政府为圆心半径6 200 m的一个范围,在此范围内合理规划生态用地,不仅会取得较大生态效益,而且会缩短整个城市的分形维数值回归的过程。最后,文章利用元胞自动机的方法,在集聚区域内对厦门岛分形回归进行了模拟分析,提出应在集聚区内转化30%的建设用地为生态用地。此集聚区不仅是城市生态规划工作的重点区域,而且也是改善厦门市整体环境质量的最佳范围。

By using TM remote sensing image taken in 2002 and 2007, urban form of Xiamen Island was analyzed by fractal tools. Results indicated that the fractal values ascended from 1.804. in 2002 to 1.847 in 2007, which had exceeded the ideal value of 1.71±0.02. In consideration of law of urban development, fractal value of Xiamen would grow slowly and gradually return to the ideal value of 1.71. The optimum range using an area-radius relationship method was determined, within which increasing the amount of green areas would bring the greatest ecological benefits and shorten the time that fractal value returns to the ideal value. The range was within a 6,200 m radius of the entrance to the site of Government of Xiamen. The process of returning to the ideal value was simulated using the cellular automata （CA） in the gathered region, and 30% built-up land was proposed to be changed into green areas. The gathered region is the key area of urban ecological planning and the optimum range to increase ecological benefits to the whole city.