Study On The Method Of Extracting Wetland Information From Danjiang Wetland

Wetland resources is an important natural resource.In order to understand the water resources of the Danjiang Wetland Reserve that the water source of the middle route project of the South-to-North Water Diversion Project,the wetland resources are guaranteed to ensure the safety of drinking water in the Beijing-Tianjin-Hebei region.In this paper,I take the method of Normalized Difference Water Index(NDWI)and Modified Normalized Difference Water Index(MNDWI)and other methods to extract the water resources.But the region to extract the water at the same time the impact of hillside shadows,making the extraction accuracy is not satisfactory.In order to solve this problem,a new method of DMNDWI is proposed,which can effectively remove the shaded area of the mountain,and the extraction precision is greatly improved.Finally,the influencing factors and changing trend of water resources change in each historical period are analyzed.For the better protection of the South-North Water Diversion Center to provide information on the water source.The main contents and research conclusions of this paper are as follows:(1)According to the Landsat satellite data of this study area,the traditional single-band threshold method,multi-band spectral correlation method,Normalized Difference Water Index(NDWI)and Modified Normalized Difference Water Index(MNDWI)according to Modified Normalized Difference Water Index(MNDWI)to obtain the highest accuracy.(2)In view of the interference of the mountain shadows encountered in the extraction of water information,combined with the threshold of DEM data,it is possible to remove the image data of certain elevation image by removing the film,which can effectively improve the water Accuracy.Combined with the above optimal extraction method MNDWI method to obtain a new extraction method DMNDWI the highest extraction accuracy.(3)The time span of this study has been directly related to the annual rainfall in the wetland of Danjiang River from 1987 to 2015,so it is necessary to determine the influence of Danjiang.The main factor of the amount of water in wetland parks isprecipitation.(4)After the completion of the South-to-North Water Diversion,the extraction of the water area of several Landsat 8 data showed that the water area of the wetland showed a significant increase trend.The average water area in the past two years is145.06 km~2 and the standard deviation is 29.53 km~2.The probability of the statistical concept P {| X-μ | <σ} = 68.27%,which falls within the range of(μ-δ,μ + δ)=(125.53 km~2-164.59 km~2),The lest of the area is 125.53 km~2,so,It can be provide a solid water supply for the middle of the South-North Water Diversion.