Spatio-temporal Analysis Of Traffic Environment Based On Ship Trajectory Big Data

In recent years,with the development of digitalization and informatization of shipping industry,massive shipping data have been accumulated.In particular,widespread applications of AIS(Automatic Identification System)generate a large number of ship trajectory data,which consists of large amount of value.How to reconstruct and analyze traffic environment spatio-temporally becomes the focus of this paper.Through comparative analysis,this paper chooses non-relational database MongoD-B as storage which has abilities of the high concurrent read,strong scalability and excellent geographical index to support ship trajectory data,and chooses WebGL(Web Graphic Library)which can directly call computer's GPU(Graphics Processing direct Unit)on the web page without plug-ins to support big data visualization,and has deeply studied some aspects including ship trajectory web visualization framework,ship trajectory synchronizing and playback,ship traffic environment spatio-temporal analysis model,finally accomplishes spatio-temporal analysis and display from different perspectives based on AIS trajectory data in the waters of the Yangtze River.The main work is done as follows:(1)The Web visualization framework design based on ship trajectory big dataDuring designing ship trajectory big data visualization framework based on B/S(Browser/Servers)structure,the back-end uses Node.js to build server and MongoDB database to store ship historical trajectory data.Socket.IO builds real-time communicate-on chain.The front-end uses WebGL technology and D3 graphics library to achieve ship trajectory data visualization based on Web browser.(2)Spatio-temporal reconstruction of traffic situation based on ship trajectoryThis section has studied methods that can quickly and efficiently extract related ship trajectories from massive data based on the extent of traffic environment and time and researched key technologies including trajectory classification and storage,reconstructio-n,updating,playback and spatial relation building between ships.And finally spatio-temporal reconstruction and persistent evolution accomplished on the web-end lays a foundation for spatial-temporal analysis.(3)Spatio-temporal visualization analysis of traffic environmentThis section has studies visualizing methods including grid chart,block charts,heatmap and complicated curves by the means of WebGL and D3 on the basis of spatio-temporal reconstruction of traffic environment,and accomplished visualizing analysis of dynamic parameters,consisting of traffic density,situation pressure,risk degree of collision and ship exhaust emission evolving over time,which are characteristics of traffic environment by choosing appropriate methods.