20世纪下半叶上海城市景观镶嵌结构演变的数量特征与分形结构模型研究

Quantitative analysis and fractal modeling on the landscape mosaic and its evolutionary process of Shanghai in the period from 1947-1996

以上海中心城区为空间范围,以RS和GIS为技术手段,运用多样指数、优势度、破碎度、分离度等指标,研究20世纪下半叶以来上海城市景观镶嵌结构及其演变的数量特征;运用分形理论建立各种景观形态的分形结构模型,以分维数为依据分析各种景观形态的复杂性;基于GIS的空间分析功能,探讨影响景观格局及其演变的主要因素。研究结果表明:(1)上海城市景观的空间扩展,在空间上和时间都是不均匀;(2)随着时间的推移,景观多样性和破碎度变大。优势度变小;(3)住宅、工矿和其它城市景观的分离度明显地呈减小趋势,农田和村镇的分离度呈增大趋势,道路和河流水域的分离度变化幅度不大;(4)各种景观斑块形态的复杂性程度(分维数的平均值)排序为:道路>河流水域>农田>住宅>村镇>工矿>在建景观>其它城市景观;(5)从各种景观形态的演变过程来看,住宅斑块形态逐渐趋于复杂化,斑其块形态的分维数呈缓慢地增大趋势;工矿、道路、其它城市景观、农田、村镇等五种景观斑块形态的变化,经历了由简单到复杂,再到简单的变化过程,其分维数在1947—1988年期间呈增大趋势,1988年时增至最大,随后开始逐渐减小;(6)影响上海城市景观格局及其演变的因素主要包括河流廊道、原有基础、交通廊道、经济发展、规划控制等几个方面。

On the research background of the central area of Shanghai city, the mosaic structure of landscape was studied by using quantitative methods of landscape ecology based RS & GIS in this paper. Firstly, by using remote sensing image, we classified the landscapes into eight kinds, which were respectively residential area, industrial area, road, other urban landscape, farmland, village & small town, building area, river & other water area. Secondly, we designed and set up a geographical information system (GIS) based on the digital data of remote sensing image, field investigation data and other data, and figured out the digital map of landscape mosaic. Thirdly, depending on the spatial analysis function of GIS, we calculated the index of diversity, dominance, fragment, isolation and fractal dimension of each landscape in different periods. Fourthly, basing on the spatial analysis function of GIS, we analyzed main factors that affect the landscape mosaic and its evolutionary process. The main conclusions of the paper were as the following: (1) The expanding model of urban landscape of Shanghai is different from other Chinese cities, which expand from center to periphery evenly, The expanding of urban landscape of Shanghai is uneven not only in space but also in time; (2) The diversity and fragment of landscape mosaic are enlarging while the dominance is reducing with time; (3) Isolations of residential area, industrial area, and other urban landscape are reducing while which of farmland, village & small town are enlarging with time. The isolations of road and river & other water area are not changing with time; (4) Fractal dimensions of landscape types from high to low are respectively road, river & other water area, farmland, residential area, village & small town, industrial area, building area, other urban landscape, The rank shows the complexity of landscape types; (5)From the point of the evolvement process of patch forms, the patch forms of residential area become more and more complex gradually, while the fractal dimension of which increase slowly. Some patch forms including industrial area, road, and other urban landscape, farmland and village & small town, which undergo from simple to complicate, then from complicate to simple, the fractal dimensions of which keep the increasing trend from 1947 to 1988, the fractal dimensions reach climax in 1988, then reduce gradually; (6) The main factors affecting landscape mosaic and its evolutionary are respectively river corridors, original base of city, traffic corridors, city development, and city plan.