基于大规模船舶轨迹数据的航道边界提取方法

Extraction method of marine lane boundary from exploiting trajectory big data

传统的道路数据获取方法成本高、更新慢等无法适用于海洋航道的获取,从众源轨迹数据中提取道路或航道信息具有成本低、更新快等特性,然而,由于船舶轨迹数据噪声多、数据量大、不同区域分布不均使得航道边界提取面临较大挑战。针对该问题,提出一种基于大规模船舶轨迹数据进行航道边界提取的方法。首先对大规模的船舶轨迹数据进行并行化去噪、插值、轨迹分段;然后,基于并行化及基于Geohash编码的空间聚类,将轨迹数据化简为多个方形区域的点集数据;其次,对其进行窗口划分,对传统的Ni Black方法进行扩展,提出Spatial Ni Black算法,对方形区域进行航道识别;最后,提出一种新的提取算法del-alpha-shape,基于航道识别结果获得航道边界。理论分析与实验结果表明,所提方法在最大密度值是200,最小密度值是10,窗口长和宽分别为5和5时,可同时达到86. 7%的准确率和79. 4%的召回率。实验结果表明,该方法可以从大规模的轨迹数据中提取有价值的航道边界,是一种有效的航道提取方法。

The traditional road information extraction method is high-cost and slow-update. Compared with it, road or marine lane information extraction from crowdsourcing trajectory data is low-cost and easier to update. However, it is difficult to extract lane boundary due to vessel trajectory data with high noise, large data volume and uneven distribution across different regions. To solve this problem, an extraction method of marine lane boundary from exploiting trajectory big data was proposed. Firstly, the parallelized denoising, interpolation and trajectory segmentation for trajectory big data was conducted.Then, based on parallelization and Geohash-encoded spatial clustering, trajectory data was simplified into multiple square regions. The regions were divided and the Ni Black method was extended as Spatial Ni Black algorithm to recognize regions on lane. Finally, based on the filtering results, del-alpha-shape algorithm was proposed to construct a Delaunay triangulation network and obtain marine lane boundary. The theoretical analysis and experimental results show that the proposed method can achieve an accuracy of 86. 7% and a recall rate of 79. 4% when the maximum density value is 200, minimum density value is10, length and width of window are 5 and 5 respectively. The experimental results show that the proposed method is effective to extract valuable marine lane boundaries from large-scale trajectory data.