Calculation And Application Of Navigable Width Based On Characteristics Of Ship Traffic Flow

With the rapid development of international trade and social economy,the marine cargo transportation is still developing rapidly.The trend of large-scale and rapid ships is increasingly obvious.The traffic flow of ships in the navigable waters is obviously increasing,the ship density is increasing,and the ship traffic structure is becoming complex.At the same time,the rapid development of computer technology,space positioning technology,modern communication technology and Internet technology makes it more convenient to study marine traffic,especially the development and wide use of AIS,which has accumulated a lot of data for the study of marine traffic flow.For ocean big data,mainly including ship basic information,location,navigation data,etc.,the huge data volume of marine traffic data itself plays an important role in the study of marine functional area planning,marine traffic planning,marine facilities construction,etc.Based on a large number of historical AIS traffic flow data,this thesis analyzes the distribution characteristics of maritime traffic flow,and constructs the traffic flow analysis model with image algorithm,so as to effectively identify the traffic flow route and analyze the navigable width.The main work includes the following aspects.(1)Based on the principle of image detection,a traffic streamline detection model is constructed.The analysis of AIS big data of ship traffic flow is transformed into the numerical analysis of matrix space through the model.For any selected sea area,the density of ship traffic flow in the area can be calculated.Combined with geographic information analysis,different grid sizes can be selected to form density matrix,which can establish numerical spatial distribution for traffic flow center detection.(2)Considering all kinds of possible factors that cause the abnormal extremum of local data,this thesis adopts the nonlinear filtering algorithm to determine the convolution template,uses the median filtering to remove the abnormal point value in the density matrix of traffic flow,effectively reduces the influence of the abnormal extremum of density on the detection of traffic flow centerline,and determines the density threshold of the detection of traffic flow centerline according to the knowledge of mathematical statistics Detect the center line of traffic flow effectively.(3).Based on the statistical knowledge,the density distribution of traffic flow is analyzed.After the center line is detected,the width of the ROI maritime traffic flow is calculated.Compared with the Gaussian fitting and kernel density estimation,the threshold value of the width and density of traffic flow is determined in the matrix space Thus,the width of traffic flow and the location of traffic flow boundary are determined,the route of traffic flow is effectively identified,and the characteristic distribution of threshold traffic volume of traffic flow is statistically analyzed.(4)Using Python 3.6,Matlab2017b and ECDIS to verify and analyze the traffic flow data formed by the ship’s historical track in the waters east of Bohai Sea,and extract three main traffic routes.The results show that the model is feasible.It provides a theoretical model for marine traffic research,such as marine engineering construction evaluation,marine functional area planning,alignment system design,etc.it has a certain significance in the identification and extraction of marine routes,especially in the practical engineering applications such as coastal small boat traffic flow route planning.This thesis analyzes the characteristics of maritime traffic flow in specific water areas based on traditional traffic flow elements and combining traffic flow data mining methods.Mainly based on the algorithm model to study the characteristics of the sea traffic flow formation route,reflecting the actual state of marine traffic.The width of the traffic flow is analyzed after detecting the center line of the sea traffic flow.It provides a reference for maritime traffic planning and actual marine traffic investigation.It also provides theoretical support for the spatial layout of offshore engineering construction and the planning of marine functional areas.