Journal of Geo-information Science >
Density-Based Spatiotemporal Clustering Analysis of Trajectories
Received date: 2015-04-29
Request revised date: 2015-05-27
Online published: 2015-10-10
Copyright
Trajectory clustering, which aims to uncover the meaningful spatial distributions and temporal variations of moving objects, is of much importance in understanding potential dynamic mechanisms and predicting future development. However, placing many focuses on locational changes, many studies have made limited use of the time dimension in trajectories. This paper presents a density-based clustering method, which integrates time and space information in identifying significant migrating paths from trajectory datasets. Definition of temporal distances between any line segments decomposed from trajectories as well as the criterion of distance threshold selection is provided in detail. The experiments conducted on ocean eddies in the South China Sea demonstrate the effectiveness of this method in obtaining spatiotemporal migrating patterns. The migrating paths in the results are shortened, or separated into parts, or they turn insignificant as the effect of including time component in density clustering, which reveal more specific movement characteristics in the temporal domain covered by spatial clustering. This advantage facilitates the analysis of objects moving along the same path while displaying distinct time patterns.
WU Di , DU Yunyan , YI Jiawei , WEI Haitao , MO Yang . Density-Based Spatiotemporal Clustering Analysis of Trajectories[J]. Journal of Geo-information Science, 2015 , 17(10) : 1162 -1171 . DOI: 10.3724/SP.J.1047.2015.01162
Fig. 1 A flowchart showing the process of trajectory spatial clustering图1 轨迹空间聚类流程图 |
Fig. 2 Spatial distance between line segments图2 线段空间距离度量 |
Fig. 3 Temporal distance between line segments图3 时间距离度量 |
Fig. 4 Trajectory density of eddies in the South China Sea图4 南海涡旋轨迹密度分布 |
Tab. 1 Number of trajectories and clustering parameters表1 轨迹聚类数目和聚类参数 |
MDL-AE | MDL-CE | OD-AE | OD-CE | TP-AE | TP-CE | |
---|---|---|---|---|---|---|
轨迹数目 | 398 | 418 | 398 | 418 | 1077 | 1185 |
εs | 74 | 79 | 124 | 124 | 79 | 77 |
MinLns | 6 | 6 | 5 | 5 | 7 | 7 |
Fig. 5 Spatial clustering results of eddies’ trajectories in the South China Sea图5 南海涡旋轨迹空间聚类结果 |
Fig. 6 Spatiotemporal clustering results of eddies’ trajectories in the South China Sea图6 南海涡旋轨迹时空聚类结果 |
Fig. 7 Time distribution of movement patterns from clustering cold eddies trajectory partitions in the southern South China Sea comparing between the spatial and spatiotemporal results图7 南海南部冷涡TP方式的空间移动模式与时间移动模式时间分布对比 |
The authors have declared that no competing interests exist.
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