The in-depth understanding of the topography and geomorphologic features of the seabed constitutes the basis for human to fully understand the ocean, effectively explore the ocean and scientifically and rationally utilize the ocean. Our focus is on the optimization of line layout of multi-beam sounding technology in seafloor topographic mapping, aiming to explore the reasonable layout strategy under the dual objectives of ensuring comprehensive coverage and efficient measurement[1]. As a key tool to obtain basic spatial geographic information of water area, multi-beam sounding system has a direct influence on the selection of direction and location of survey lines, especially in the face of complex seabed topography, the change of strip coverage between adjacent survey lines may lead to regional missing survey phenomenon. Aiming at the overlapping rate control problem in the layout of survey lines, our research uses the sine theorem and other geometric principles to establish the coverage width and overlapping rate model under the specific situation that the survey line is along the isobath direction, and reveals the law that the coverage width of the multi-beam sounding system is positively correlated with the water depth under the condition of fixed survey line interval, and gives specific numerical results through empirical data. The paper further discusses the layout scheme of survey lines with optimal measurement efficiency, defines the area coverage index per unit slope length, and constructs the corresponding layout models for the two special terrain types projected as isosceles trapezoid and rectangular parallel to the isodepth line. Through the stepwise optimization calculation, it is found that the layout scheme based on trapezoidal projection cannot reach the effective solution when the overlap rate is set to 20% while meeting the requirement of full coverage. Under the condition of rectangular projection, if the overlap rate is set to 10%, the optimal solution is obtained: the shortest 70 measuring lines need to be laid, and the total length of the measuring lines is 259280 meters. Moreover, the test results after a small adjustment of the overlap rate show that the solution has certain convergence, thus enhancing its possibility as the optimal solution. The research results of this paper not only deepen the understanding of the theory of line layout of multi-beam sounding system, but also provide an optimization method in practical operation, which is of great significance for improving the accuracy of ocean surveying and mapping, working efficiency and reducing resource waste.
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