基于时序NDVI数据的中国红壤丘陵区土地覆被分类研究

Land cover classification in red soil hilly region of China using multi-temporal VEGETATION/NDVI data: a case study of Poyang basin

选择位于红壤丘陵区的中国最大淡水湖——鄱阳湖及其整个流域作为研究对象,应用2000年SPOT4-VEGETATION的时序NDVI数据,结合野外实地考察和研究区相关资料,探讨了一种以地表覆盖物的光谱响应及其季节性变化特征为主要依据、以色彩作为类别命名基础的土地覆被分类新方法,构建了一个包含6个一级类别和14个二级类别的土地覆被分类方案。在此基础上,利用PCI软件中ISODATA算法以及ArcMap的空间分析功能对研究区土地覆被进行了非监督分类和判定。结果显示基于时序NDVI数据的ISODATA法分类能够较好地刻画不同土地覆被类型之间的差异性,流域的现状覆被以常绿覆被(主要是针叶林)和作物以及作物-树-草混合覆被为构成主体,三者共占鄱阳湖流域面积的94.97%。

Poyang Lake is the largest fresh lake and lies in red soil hilly region of China. Poyang basin is an important agricultural production base, especially paddy field and an area suffered from serious flood disaster. In this study, a new idea of classification for the clustering of Poyang basin land cover has been proposed based on the cover spectral response and characteristics of seasonal variability by using multi-temporal SPOT4-VEGETATION sensor data (NDVI) while land cover type is named after color. Then a two-level land cover classification system has tentatively been upbuilt. Based on it, the preliminary land cover map of Poyang basin has been derived from the unsupervised classification of NDVI digital images by applying ISODATA algorithm in PCI software and Spatial Analyst Function in ArcMap. According to the area, the total land cover density reaches 94.97%: evergreen cover is 40.05%, crop-forest-grassland mixed cover 38.29%, crops 16.63% in proportion to the Poyang basin at present.