Research Of Flood Control Decision Method Based On 3S

With the technology of Remote Sensing(RS),Geographical Information System(GIS) and Global Positioning System(GPS), this paper studies on the method and application of water vapor inspection by GPS on flood control decision, evaluation of air probable maximum precipitation, flood simulation and flood evaluation.This paper analyzes the effective range where a GPS station can measure the total at mospheric water vapor, studies on the effective area where the GPS station in different height can measure the total at mospheric water vapor and the water vapor varied by height, makes the conclusion that only 3 to 4 GPS receivers machines can completely reflect the water-vapor variety in the river basin. After competing the GPS data and measuring the locale effect, we choose the GPS data transfer mode in the river basin of GPRS EDGE, and organise the water-vapor inspection web comprising five GPS stations: Shitan,Shikan,Shahe,Zhukeng and Qingyuan.With the principle of water vapor retrieval of GPS and the computation method of air probable maximum precipitation, we go on to compete the air probable maximum precipitation, discuss the relation and principle between the air probable maximum precipitation and actual precipitation, compare the both results of the air probable maximum precipitation from the GPS observation data and radiosonde data, accordingly improve the precision of hydrological forecasting and extend the forecasting period.Through two-dimensional unsteady flow mode and VORONOI map introduced into the separation of grid cells, modeling the flood procession and system analyzing in the research area, applying simulation technology and the softwares of three-dimensions simulation modeling, facture and so on, combining the orthophotoquad projection and DEM to process and create three-dimension terrain of the base of the beijiang river levee, then complicatedly create the three-dimension scene, and organically combining the three-dimension simulated GIS and two dimension GIS, and combining to computer network, carrying out the integration and supplement between two-dimension and three -dimension, viewing the three-dimension scene and querying the three-dimension information on the net.Study on the method of dynamic flood evaluation by RS, with the RS technology, we go to inspect the area of the flood inundating, through the method of space analyst, ascertain the capital assets or scale of all kinds of assets in the executive cells needing evaluation to different water depth separation and inundate-time separation, and go on to subarea evaluation, gathering to compete the total economical lost, and evaluating the flood expense in the protection area of the north river levee.Base on the integrated database, with the mixed stuctrure form of C/S+B/S , geographical information system collects all the results of the subsystem of GPS vapor inspecting, precipitation forecasting, flood modeling, three-dimension simulation, flood risk sorting, disaster evaluation and so on, finally forms the flood-control decision support system.