Research And Implementation Of Dynamic Updating And Spatial Analysis Of Yangtze River Riverbed

Yangtze River, which is an inartificial golden fairway, is the largest river among all rivers across through my country. Shipping of Yangtze River has very important strategic significance for China's economic development. In order to develop shipping steadily and fast, it is our obliged to ensure ships sailing safely on Yangtze River .Sailing safely on Yangtze River is a important system project. Traditional two-dimensional ENC (Electronic Navigational Chart) plays a important role in ensuring ships sailing safely, but it has weak visualization and many complex analysis are not proceeded under it. Therefore, navigation will be as easy and safe as driving a car, if we can offer an ocular and three-dimensional navigation geographical environment to sailor and relevant administrative staff, specially present the terrain under water covered up by the surface of water before sailor's eyes. In addition, in order to cooperate with the responsible fairway department to manage the channel, need to analyze the terrain of the fairway, including the terrain factor calculation, water flooding analysis and riverbed section analysis, etc. The analytical work will offer very great help to the management of the fairway. So an information system based on three-dimensional environment will facilitate the sailor and relevant administrative staff to make decision accurately and promptly very much. Thus improve ship's security and efficiency, there are extensive application prospects in systemic analysis, scheme demonstration and engineering design of planning and developing to the fairway.The paper stems from the construction of fairway 3D visualization platform of Yangtze digital fairway system and intelligent shipping demonstration project between Nanjing and Liuhekou which is a key project of Ministry of communications. The main work include:(1) Analyzed the theory data model and file fabric of ENC, realizing picking up dispersed water depth dot data from the ENC, supplying a good data for constructing riverbed DEM of Yangtze River;(2) Proceed from actual conditions of project, according to dispersed water depth dot data, through setting up regular grid model, finished the three-dimension modeling of the Yangtze riverbed, updated the riverbed by use of new water depth dot data, and integrated the riverbed DEM into land DEM;(3) Does the research of spatial analysis, including terrain factor calculation, water flooding analysis and riverbed section analysis based on the fairway riverbed DEM, which provides fairway department dredging up the fairway with a technical support and method;(4) Realizing the 3D visualization and function of spatial analysis of Yangtze River by VC++ and Direct3D based on IMAGIS platform.