| The South China Sea(SCS)is one of the world’s busiest sea lane as well as the necessary pathway for international maritime trade of China,which is related to China’s national energy safety.In recent years,the shipping routes in the SCS are frequently threatened by many factors such as extreme weather events like powerful typhoons and tsunamis,frequent activities of the piracy and maritime terrorism,major country outside the region getting involved in the SCS dispute.All these factors are closely related to spatial location.Recently spatial data collection techniques such as RS and GPS are increasingly rich and spatial anaysis technologies like multi-creteria decisin support and spatial correlation are continually abundant,which provid the possibility to analyze and assess the safety of shipping routes.Based on these advanced techniques and technologies,it’s significant to analyse the safety of shipping routes in the SCS,study the spatial extent,mode and intensity,and present improvement measures of maritime transportation safety in order to provide decision support for maritime administraton,protect people’s lives and property,protect the maritime environment and safeguard China’s national safety and interests.At present,study of navigaion safety is still in its infancy and the spatial variation is offen not consideration.Where is the shipping lanes?How is the spatial distribution of shipping lanes’ safety?How to optimize shipping lanes’ safety of the SCS?These problems are to be solved in the researches on shipping lanes’ safety.Based on multisource spatial data,the thesis solved the technical difficulties in extraction,analysis,and evaluation.Specifically,main shipping routes were extracted accurately at first,then spatial temporal distributions of the shipping lanes’ safety were revealed under the influence of terrain,hydro-meteorological,and social environment and finally measures and proposals to improve the safety of shipping routes were present.The main contents and main conclusions in this study are concluded as follows:(1)Study of shipping lanes extraction method based on trajactory cluster analysis.The shipping lane are the strip area formed by the ship trajactories between ports.The trajactories reflect the distribution characteristic of shipping lanes.Aiming at the difficulty in shipping lanes extraction based on the trajectories,this thesis presented a technique process of trajactory generation,similarity calculation and cluser analysis.Firstly shipping lanes were extracted from clusters through cluster centerline extraction.Secondly extraction results were validated by Envsat ASAR image processing and world shipping lanes.The results show that there are 14 shipping lanes extracted in the SCS,with 8 through the west water of Nansha Islands,3 shipping lanes from Guangzhou to Singpore which sailing through western,middle and eastern water.The shipping lanes of eastern Guangzhou-Singapore and Kaohsiung-Singapore are the most frequent used routes.(2)The quantitative analysis and evaluation of risk factors in shipping lanes’navigation environment.Since the safety of shipping lanes is closely related to the danger digree of navigation environment,this thesis analyzed factors that affect shipping lanes’ safety from terrain,hydrological and meteorological,and social environment,then evaluated the risk of the typical factors based on spatial analysis.The results are concluded as follows.From the aspect of terrain environment,water areas near the reefs and seashore are influenced deeply.From the aspect of hydrological and meteorological environment,navigation safety is affected by wind and wave in autumn and winter,espercially in the northeastern of the SCS,and affected by tropical cyclone in summer and autumn with high risk in the northern of SCS in summer and in the northeastern in autumn.From the aspect of social environment,ship density mainly affect the coast zone in the northern of the SCS and navigation safety is threaten by the piracy in the surrounding waters of Malacca Straits.(3)Spatial safety evaluation model of shipping lanes.The establishment of saptial safety evaluation model helps maritime administratice in understanding the spatial distribution of navigation safety,keeping shipping lanes in the SCS open and safe.Based on regional characteristics of the SCS,evaluation index system of shipping lanes safety was established,a spatial evaluation model based on OWA-GIS method was presented,safety distribution of the region and shipping lanes in the SCS was assessed and at last effective improvement measures were presentd.The evaluation results are listed below.First,Malacca Srtait is very dangerous in navigation,all the shipping lanes through the strait are affected by the piracy.Second,autumn and winter are more dangerous in the northeastern of the SCS than other seasons,among which shipping lanes to Kaohsiung,Bass Strait,Balintang Channel are influenced most deeply,three shipping lanes to Guangzhou are also affected and other shipping lanes are affected lower.Considering maritime search and rescue accessibility,three positions are suggested to establish search and rescue points in the Scarborough Reef,Fiery Cross Reef and Cuarteron Reef,Kangtai Reef,and Zhubi Reef.Sea patrols should also been strengthened around the Nansha Islands.There are two main innocations in this paper.(1)It raises a centerline of channel extraction method based on trajectory clustering.In this study different voyage lines are generated using voluntary obserbing ship(VOS),then cluster analysis is conducted by similarity of buffer intersection measurement track line,finally channel center lines are generated based on triangulation method.(2)It constructs the spatial evalution model of shipping lanes in the SCS based on OWA-GIS.Moreover,evaluation results are calculated by order weighted average model comprehensively considering differences of indexes importance and influences of index values in different positions. |
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