粒度变化对上海市景观格局分析的影响

采用1989年上海市1∶50 000彩红外航空遥感影像解译的土地利用数据,系统分析了粒度变化对中心城区、郊区和城郊结合部3类景观格局分析的影响.结果表明:景观格局指数对粒度具有尺度依赖性,随粒度的变粗,格局指数的变化可归为单调下降、阶梯上升或单峰变化以及不规则变化3类;景观格局指数随粒度变化的曲线存在多个拐点,并对应于合适的景观格局分析尺度,上海城市景观格局分析的合适尺度为10～20 m;不同城市景观类型对景观格局指数的粒度效应具有较大影响,景观格局指数在城郊结合部表现出与城区和郊区不同的变化趋势.

Effects of changing grain size on urban landscape pattern analysis of Shanghai

The effects of changing grain size on landscape metrics play an important role in landscape pattern analysis,being one of the important and key issues in landscape ecology.In this paper,the land-use datasets derived from color-infrared aerial photos acquired in 1989 at 1:50 000 scale were employed to analyze the effects of changing grain size on the landscape metrics in central urban,urban-rural ecotone,and suburban landscape types of Shanghai.The results showed that the responses of landscape metrics to changing grain size fell into three categories.The first group of metrics decreased monotonically,the second group increased in staircase or single hump,both of them showing a consistent scaling relation with increasing grain size,while the third group showed uncertainties.There were critical points(i.e.inflexions) in the response curve for most landscape metrics,which corresponded to the suitable scale in landscape pattern analysis.For Shanghai urban landscape pattern analysis,the appropriate spatial resolution was 10-20 m.Different urban landscape types also had effects on the metrics responses to changing grain size,and the metrics in urban-rural ecotone had different variation trends with those in central urban and suburban landscape types.