中国特大城市空间形态变化的时空特征

基于国家资源环境数据库动态土地利用数据,借助GIS软件支持,分别计算了1990年和2000年中国31个特大城市平面轮廓形状的分维、紧凑度和形状指数以及城市的用地扩展类型。结果表明,从1990年到2000年,中国31个特大城市空间形态的总体变化趋势是,城市用地空间扩展类型以填充类型为主,外延类型相对较少且主要发生在发展限制较小的平原地区。总体上,分维呈减少趋势且南方城市大于北方城市,形状指数有减少,城市空间形状有紧凑化趋势。综观1990年和2000年中国31个城市的分维、紧凑度和形状指数的数据,可以看出广州、南昌、济南、成都、北京和上海等城市形状变化比较大,而兰州、太原和唐山等城市形状变化很小。若用地扩展为填充类型,则分维减少,紧凑性增加,形状指数减少;相反,若用地扩展为外延类型,分维增加,紧凑性降低,形状指数增加。

Spatial-temporal Changes of Urban Spatial Morphology in China

Fractal dimensions, compact ratios, shape indices and types of urban l and expansion of 31 Chinese cities in 1990 and 2000 were computed by using dynam ic land-use data from the National Resources and Environmental Database establis hed by the IGSNRR, CAS. The results show, during the period from 1990 to 2000, t hat the type of urban land expansion belongs mostly to the 'extension' types and the cities with the 'filling' land expansion are almost located in the flat reg ions. Generally, fractal dimensions of 31 Chinese cities were inclined to reduce and fractal dimensions of the southern cities are more than those of the northe rn cities, compact ratios of most of the cities increased, urban shape indices o f most of the cities decreased, during the period from 1990 to 2000. In all the 31 cities, the changes in the planar configurations of Guangzhou, Nanchang, Jina n, Chengdu, Beijing and Shanghai are the greatest, while the changes of Lanzhou, Taiyuan and Tangshan's configurations are the least. Such a simple rule is reve aled that the fractal dimensions would reduce, compact ratio would increase and shape index would decrease if the type of urban land expansion belongs to the 'f illing' type and vice versa.