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Highlights • Propose a framework to find stop episodes from spatio-temporal trajectories. • Incorporate relevant real places from OpenStreetMap for place matching. • Propose a place matching algorithm that overcomes the place ambiguity issue. • Provide experimental results supporting the effectiveness of proposed method. • Provide a case study demonstrating the validity of proposed framework. Abstract This paper introduces a place-matching pattern mining approach that detects place-matching patterns from raw spatio-temporal GPS trajectories using real-world places from OpenStreetMap. The approach begins by annotating raw trajectory recordings as either stopping or moving. It then groups contiguously stopping entries into so-called stop episodes; each of which is then associated with a number of potential stop place candidates from the real-world place repository OpenStreetMap. As each stop episode may have multiple place candidates, the proposed approach uses a Hidden Markov Model to probabilistically match each sequence of stop episodes to its most likely sequence of visited real-world places. The result of this stop episode formulation and place-matching is that the original trajectories are transformed into a discrete, greatly simplified, and more semantically meaningful sequence of place visitations. This format enables the last step of our approach where frequent itemsets and sequential patterns are extracted using traditional approaches. Experimental results with real and synthetic datasets demonstrate our approach's running time performance, robustness to GPS noise, dataset compression, and matching accuracy. Additionally, a case study using human trajectories from the real-world Geolife dataset reveals many interesting and seemingly real patterns. These findings suggest the general validity and applicability of our approach as a place-matching trajectory data mining approach. [ABSTRACT FROM AUTHOR]

Stop and move information can be used to uncover useful semantic patterns; therefore, annotating GPS trajectories as either stopping or moving is beneficial. However, the task of automatically discovering if the entity is stopping or moving is challenging due to the spatial noisiness of real-world GPS trajectories. Existing approaches classify each entry definitively as being either a stop or a move: hiding all indication that some classifications can be made with more certainty than others. Such an indication of the “goodness of classification” of each entry would allow the user to filter out certain stop classifications that appear too ambiguous for their use-case, which in a data-mining context may ultimately lead to less false patterns. In this work we propose such an approach that takes a noisy GPS trajectory as input and calculates the stop probability at each entry. Through the use of a minimum stop probability parameter our proposed approach allows the user to directly filter out any classified stops that are of an unacceptable probability for their application. Using several real-world and synthetic GPS trajectories (that we have made available) we compared the classification effectiveness, parameter sensitivity, and running time of our approach to two well-known existing approaches SMoT and CB-SMoT. Experimental results indicated the efficiency, effectiveness, and sampling rate robustness of our approach compared to the existing approaches. The results also demonstrated that the user can increase the minimum stop probability parameter to easily filter out low probability stop classifications—which equated to effectively reducing the number of false positive classifications in our ground truth experiments. Lastly, we proposed estimation heuristics for each our approaches’ parameters and empirically demonstrated the effectiveness of each heuristic using real-world trajectories. Specifically, the results revealed that even when all of the parameters were estimated the classification effectiveness of our approach was higher than existing approaches across a range of sampling rates. [ABSTRACT FROM AUTHOR]

Trajectory data is rich in dimensionality, often containing valuable patterns in more than just the spatial and temporal dimensions. Yet existing trajectory clustering techniques only consider a fixed number of dimensions. We propose a general trajectory clustering methodology which can detect clusters using any arbitrary number of the n -dimensions available in the data. To exemplify our methodology we apply it an existing trajectory clustering approach, TRACLUS, to create the so-called, ND-TRACLUS. Furthermore, in order to better describe the trajectory clusters uncovered when clustering arbitrary dimensions we also introduce, Retraspam, a novel algorithm for n -dimensional representative trajectory formulation. We qualitatively and quantitatively evaluate both our methodology and Retraspam using two real world datasets and find valuable, previously unknown higher dimensional trajectory patterns. [ABSTRACT FROM AUTHOR]

We focus on the problem of using contiguous SPM to extract succinct, redundancy controlled patterns from large vehicle trajectories. Although there exist several techniques to reduce the contiguous sequential pattern output such as closed and max SPM, they still produce massive redundant pattern outputs when the input sequence database is sufficiently large and homogeneous — as is often the case for vehicle trajectories. Therefore, in this work we propose DC-SPAN: a distinct contiguous SPM algorithm. DC-SPAN mines a set of sequential patterns where the maximum redundancy of the pattern output is controlled by a user-specified parameter. Through various experiments using real world trajectory datasets we show DC-SPAN effectively controls the redundancy of the pattern output with trade-offs in pattern distinctness. Additionally, our experiments also indicate that DC-SPAN efficiently computes these patterns, incurring only a marginal running time cost over existing state-of-the-art contiguous SPM approaches. Lastly, due to the less redundant and more succinct pattern output we also briefly explore visualisation as a useful technique to interpret the discovered vehicle routes. [ABSTRACT FROM AUTHOR]

Highlights: [•] Propose an arbitrary shape detection regions-of-interest mining algorithm. [•] Propose a sequential trajectory pattern mining framework for Flickr geo-tagged photos. [•] First time analyzing geo-tagged photos using sequential trajectory pattern mining. [•] Experiments supporting the applicability, and effectiveness of our proposed algorithm. [ABSTRACT FROM AUTHOR]