title: [Study on the relationship between Terra-MODIS image and the snail distribution in marshland of Jiangning county, Jiangsu province].
abstract: OBJECTIVE
  To analyze the relationship between the normalized difference vegetation index (NDVI) and the snail distribution in marshland of Jiangning county in Jiangsu province, and to explore the utility of Terra-MODIS image map in the small scale snail habitats surveillance.
  
  
  METHODS
  NDVI were extracted from MODIS image by vector chart of the snail distribution using ArcView 8.1 and ERDAS 8.5 software. The relationship between NDVI and the snail distribution were Investigated using Bivariate correlations and stepwise linear regression.
  
  
  RESULTS
  The snail density on marshland was positively correlated with the mean NDVI in the first ten-day of May and the maximum NDVI (N(20max)) in the last ten-day of May. Incidence of pixel with the live snail on marshland was positively correlated with the mean NDVI (N(2mean)) in the first ten-day of May. An equation Y(1) = 0.009 47 x N(20max) (R(2) = 0.73), Y(2) = 0.018 6 x N(2mean) (R(2) = 0.906) was established.
  
  
  CONCLUSIONS
  This study showed that the Terra-MODIS satellite images reflecting the status of the vegetation on marshland in Jiangning county could be applied to the study to supervise the snail habitat. The results suggested that MODIS images could be used to survey the small scale snail habitats on marshland.
authors.affiliation: Department of Epidemiology, Faculty of Preventive Medicine, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.forename: Zhi-ying
authors.initials: ZY
authors.lastname: Zhang
authors.forename: De-zhong
authors.initials: DZ
authors.lastname: Xu
authors.forename: Zhi-dong
authors.initials: ZD
authors.lastname: Sun
authors.forename: Xiao-nong
authors.initials: XN
authors.lastname: Zhou
authors.forename: Zi-li
authors.initials: ZL
authors.lastname: Gong
authors.forename: Shi-jun
authors.initials: SJ
authors.lastname: Liu
authors.forename: Cheng
authors.initials: C
authors.lastname: Liu
authors.forename: Bin
authors.initials: B
authors.lastname: Xu
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D000818:Animals; D001947:Breeding; D002681:China / Q000453:epidemiology; D004463:Ecology; D004784:Environmental Monitoring; D062665:Epidemiological Monitoring; D006801:Humans; D017215:Satellite Communications; D012554:Schistosomiasis japonica / Q000453:epidemiology / Q000635:transmission*; D012621:Seasons; D012908:Snails / Q000254:growth & development / Q000469:parasitology* / Q000502:physiology*