遥感图像非监督分类在退田还湖区钉螺孳生地监测的初步应用  

The use of unsupervised classification of Landsat-5 TM images in analysing the types of vegetation in the areas of “breaking dikes or opening sluice for water store”

作　　者：赛晓勇[1] 闫永平[1] 徐德忠[1] 张治英[1] 蔡凯平[2] 李岳生[2] 周晓农[3] 

机构地区：[1]第四军医大学预防医学系流行病学教研室,西安710033 [2]湖南省血吸虫病防治所 [3]中国疾病预防控制中心寄生虫病预防控制所

出　　处：《中华流行病学杂志》2005年第2期88-91,共4页Chinese Journal of Epidemiology

基　　金：国家"十五"科技攻关课题资助项目 (2 0 0 1BA70 5B0 8)

摘　　要：目的　探讨退田还湖前后集成垸试点植被类型的变化及植被类型与钉螺孳生地活螺密度之间的关系。方法　应用遥感技术将集成垸试点退田还湖前后标化植被指数 (NDVI)图非监督分类后进行比较 ,结合现场调查确定植被类型。结果　退田还湖前各钉螺孳生地平均NDVI值介于 12 6～183之间 ,植被类型以水稻、棉花和油菜为主 ;退田还湖后平均NDVI值介于 15 2～ 193之间 ,植被类型以意大利杨树 (意杨 )林、芦苇和杂草为主 ;发现钉螺孳生面积由 6 4 .6 4 %上升为 6 6 .4 7% ;各钉螺孳生地一般以多种植被混合为主 ,很少有单一植被类型 ,活螺密度以意杨林、芦苇混合类型最高 ,其次为意杨林、杂草混合类型 ,最后为单一芦苇类型。结论　单纯运用非监督分类不能识别植被类型 ;意杨林、芦苇和杂草与活螺密度关系密切 ,还应进一步研究。Objective To clarify the change of vegetation types and its relationship between the density of alive-snails in the areas of “breaking dikes or opening sluice for water store” in Jicheng. Methods Synthesized false color images of Jicheng before and after 1998(1994 and 2003) were classified without supervision and results were compared. Vegetation types were identified on the spot. Results Normalized difference vegetation index(NDVI) of snail habitats before 1998 were between 126 and 183 in Jicheng,whose vegetation types were mainly paddy,cotton and cabbage. NDVI of snail habitats in Jicheng after 1998 were between 152 and 193 whose vegetation types were mainly poplar forest,bulrush and grass. Areas of snail habitats increased from 64.64 % to 66.47 %. Snail habitats were mostly composed of mixed vegetation types and mono-typed vegetation was hardly found. According to the density of alive-snails orders from high to low were poplar forest and bulrush,poplar forest and grass,bulrush. Conclusion Vegetation types would not be identified by unsupervised classification only. Poplar forest,bulrush and grass were closedly related to the density of alive-snails.

关 键 词：意杨 植被类型 杂草 芦苇 非监督分类 密度 湖区 钉螺孳生地 监测 标化 

分 类 号：R184[医药卫生—流行病学]