Abstract
aIn this paper, band-combining operation is applied to extract water body area of three different period remote sensing
pictures. Based on the Beijing wetland management classification system of wetlands and wetland patches census data,
through the superposition of space under the counter-analysis and recursive speech, build a VBA classification, different
stages of the wetlands water are separated automatically in order for the organic connection and unity of data from
wetland administration section and remote sensing data. The results show that: (1) Decision tree is a good way to get the
whole water information. All the information of water can be extracted by tm2 + tm3> tm4 + tm5, but there are still
some mixed information. Towns and clouds can be removed when tm5 and tm7 less than a specific threshold, and
shadow of the mountain can also be removed well when tm3-tm4 are greater than a specific threshold. (2) The urban
wetlands can be obtained rapidly with the secondary development of VBA functions in GIS. (3) This classification
method has high accuracy, the overall classification accuracy is 91.8%, kappa statistics is 0.88, and this method avoid
post-processing work, is very time-sensitive.
