Information Extraction And Change Research Of The Wetlands Along The Yangtze River And Lakes In Anqing

Being unique in various environmental functions and ecological effects, wetlands have been playing an extremely important role in keeping the ecological balance of the earth surface, and for this reason it gets great concern. It is very crucial how to acquire the basic information of wetlands rapidly and accurately.Wetlands along-Yangtze and lakes in Anqing is the important component of freshwater wetlands in middle and lower Yangtze. It also has complicated functions. Based on RS and GIS technology and under the support of 1989, 1995. 1999. 2002 and 2007 five periods of TM images as the main research material, Remote Sensing Methods which used in wetlands along the Yangtze River in Anqing were studied. The main research contents and results are as follows:(1) According to the Wetlands Convention and China Wetland Resources Investigation and Monitoring Technology and combined with image interpretation and field surveys and research, wetland remote sensing classification system of the study area were established.(2) In the basis of comparative analysis of domestic and international wetland information extraction method's advantages and disadvantages, new index and relationship between spectrums were built by HSV. IHS. LBV. K-T transformations and sampling analysis. The decision tree method system of wetland information automatic extraction was established based on Complex Transformation. The method can eliminate the impact of the subjective factors in selecting the threshold scope. Seven types of wetlands of the study area were extracted more rapidly, accurate objectively.(3) Three indicators such as statistical indices (content categories of spot diagram around the perimeter, quantity, area). Fractal Dimension and Stability Index were selected in the theoretical basis of landscape ecology and fractal theory. The dynamic changes of wetlands landscape pattern in recent 20 years of the study area were quantitative analysised. And wetland evolution of the study area roughly through three stages: worse—restoration—benign development. In recent years, along with the protection of the ecological environment of wetland, there also exist problems in Anqing. The natural wetland areas still reduce gradually and rivers or lakes have poor stability. The wetland environment protection of research area is still facing a seriously situation.