应用LANDSAT ETM+图像监测江宁县江滩钉螺孳生地

Application of LANDSAT ETM+ images in the surveillance of marshland hab itat of oncomelenia snails in Jiangning county

目的 :研究应用陆地卫星 7(LandsatEnhancementThematicMapperPlus,LandsatETM +)图像监测江宁县江滩钉螺孳生地地表特征。方法 :对Landsat7获取的TM 2、TM3、TM4图像伪彩色合成 ,然后在ERDAS8 5软件支持下进行非监督分类 ,并将分类结果与钉螺分布空间矢量图层重叠 ,分析钉螺孳生地地表特征。结果 :ETM图像非监督分类可将江宁县江滩地表分为 10类 ,除可识别的水体及裸露地表外 ,其余各类需实地勘察才能确定其所代表的地表景观。将分类结果与钉螺分布空间矢量图层重叠分析发现 ,江宁县江滩钉螺孳生地中 ,主要为 5 ,6 ,7,9四类地表景观 ,其中以 6 ,9两种地表的比例最大 ,且以 6 ,9两种地表为主的孳生地的钉螺密度明显高于其他孳生地的螺密度 (u =19 0 0 ,P <0 0 5 ) .结论 :非监督分类的 5 ,6 ,7,9类 (尤其是 6 ,9两类 )景观适宜于钉螺的孳生与繁殖 ,同时说明应用LANDSATETM

AIM: To explore the application of LANDSAT E TM+ images in the surveillance of snail habitats in marshland of Jiangning Count y. METHODS: False-color composition images from TM2, TM3 and TM4 of LANDSAT ETM+ were used to analyze the characteristics of land-cover in the marshland snail habitats in Jiangning County by unsupervised classificati on in ERDAS IMAGINE 8 5. RESULTS: By means of unsupervise d classification of the LANDSAT ETM+ false-color image, the land-covers of marsh land in Jiangning County were classified into 10 types, which included water, ba re soil and other 7 types of landscape. The vegetation and landscape correspondi ng to those of the above classified land-covers were not confirmed by on the spo t investigation. Overlaying the classified images with the vector layer for the distribution of snail habitats demonstrated that the land-covers in the snail ha bitats of marshland in Jiangning County were mainly the type 5, 6, 7 and 9. And the Mann-whitney test showed that the density of snails in the habitats with the type 6 and 9 as their major land-cover was higher than that in other habitats ( P<0.05 ). CONCLUSION: The vegetations and landscapes corresponding to those of the classified type 5, 6, 7 and 9 may be the suitable habitats for the survival of snails and for the transmission of the schistosomia. LANDSAT ETM+ images can be used in the surveillance of marshla nd snail habitats in Jiangning County, but further study should be done.