Tide controlling of topographic survey for the Hangzhou Bay Major Bridge

The underwater topography of the Hangzhou bay is very complicated and its tide is so strong, that arranging the tide stations reasonably, calculating the tide lever by using triangle zone method and surveying in proper time can get more precise data. Usually, start to survey between 3 hours before high tide and 3 hours after high tide, can succeed in averting the forth brank while linking up survey of shallow tidesand. It is an available way that examine line must be layed on surveying water depth in order to examine water depth product and tide rectification. So the pricsion of landforms survey can be improved.