Abstract:

Objective   To identify snail habitats by using remote sensing (RS) and geographic in-
formation system (GIS) automatically.  Methods   The images of RS for abundant-water period and
low-water period in Poyang Lake were extracted and Normalized Difference Water Index (NDWI)
was computed and extracted, respectively. The regions of "water in summer and land in winter
were determined by subtracting the NDWI in the two images.  Then Normalized Difference Vegeta-
tion Index (NDVI) was computed in the above extracted regions, and the regions with vegetation
were extracted automatically. Finally, the extracted regions were compared with field snail materi-
als and analysed by the method of overlapping. Results   The regions appropriate for snails to live
were the intersection regions of NDWI>0. 05 and NDVI>0. 20 in the image of Poyang Lake.  Con-
clusion  The snail habitats and the related areas could be obtained easily by means of RS and GIS
techniques, according to the ecological conditions of snail breed.   
 

Key words:  Oncomelania hupensis, Schistosomiasis, Snail index, Remote sensing, Geographic
Information System, Marshland and lake regions

摘要：

目的利用遥感与地理信息系统(GIS)技术自动确定钉螺孳生地。方法  利用丰水期与枯水期遥感图像，分别自动计算与提取水体指数(NDWI)，两图像水体指数相减，获得“冬陆夏水”区域；在“冬陆夏水”区域计算植被指数(NDVI)，并提取有植被覆盖的区域；将提取的区域与已有螺情资料进行空间叠加对比分析。结果在鄱阳湖区，两时相中NDWI>0. 05的区域之差与NDVI>0. 20的区域的交集，为适宜钉螺孳生的区域。结论根据适宜钉螺孳生的生态条件，利用遥感与GIS技术可以快速获得钉螺的孳生地及其面积。    

关键词: 钉螺；血吸虫病；钉螺指数；遥感；地理信息系统；湖沼地区