摘要:
为分析武汉市建设用地扩张时空特征,基于1990,2000,2005和2010年获取的Landsat影像数据,利用面向对象分类方法提取建设用地信息;采用城市扩张速度(expansion speed index,ESI)、扩张强度(expansion intensity index,EII)及综合扩张程度指数(expansion degree index,EDI)和标准差椭圆(standard deviational ellipse,SDE)空间分析方法分析该市1990―2010年建设用地扩张时序及空间分异特征.结果表明: 武汉市建设用地呈扩张趋势,20 a间扩张了749.9 km2,前期10 a、中期5 a和后期5 a间扩张面积分别占扩张总面积的19.06%,33.33%和47.61%;3个时段的ESI和EII均呈增大趋势,后期扩张程度尤为剧烈.SDE分析表明,20 a来武汉市建设用地空间分布呈离散趋势,前期局部扩张,中期趋于均衡扩张,这2个时段呈"东北→西南"空间分布格局;后期全局均衡扩张,空间分布不存在方向性.研究结果将有助于武汉市建设用地的理性扩张决策.
Abstract:
In order to analyze the spatial-temporal variations of construction land expansion in Wuhan City, the authors obtained construction land data by using object-oriented classification method based on Landsat data acquired in 1990, 2000, 2005 and 2010.Urban expansion indices, which included expansion speed index (ESI), expansion intensity index(EII) and integrated expansion degree index (EDI), were used to quantitatively analyze temporal variations of construction expansion.And standard deviational ellipse(SDE)method was employed to investigate the spatial dynamics.The results show that the area of construction land in Wuhan City increased continuously, with a total increase of 749.9 km2 in two decades.The proportion of construction land expansion in earlier ten years, middle five years and later five years was 19.06%, 33.33% and 47.61%, respectively.The values of ESI and EII tended to increase, and the expansion degree was especially strong during 2005―2010 period.The spatial distribution of the construction land was discrete.Construction land partially extended in the earlier decade and tended to expand evenly in the middle five years.And the distribution of the construction land in the two periods exhibited a spatial pattern "spanning northeast to southwest".In the later five years, construction land expansion was balanced in every direction with no directivity.This study may provide decision support for the rational expansion of construction land in Wuhan City.
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