Spatio-Temporal Graphs Beyond Grids: Benchmark for Maritime Anomaly Detection

TL;DR

This paper introduces a new benchmark dataset for maritime anomaly detection using spatio-temporal graphs, addressing the challenge of irregular, non-grid data in maritime traffic systems.

Contribution

It extends the OMTAD dataset into a benchmark for graph-based anomaly detection across multiple granularities in maritime traffic.

Findings

Provides a systematic evaluation framework for maritime anomaly detection.

Enables assessment of methods at node, edge, and graph levels.

Facilitates reproducibility and methodological advances in non-grid spatio-temporal systems.

Abstract

Spatio-temporal graph neural networks (ST-GNNs) have achieved notable success in structured domains such as road traffic and public transportation, where spatial entities can be naturally represented as fixed nodes. In contrast, many real-world systems including maritime traffic lack such fixed anchors, making the construction of spatio-temporal graphs a fundamental challenge. Anomaly detection in these non-grid environments is particularly difficult due to the absence of canonical reference points, the sparsity and irregularity of trajectories, and the fact that anomalies may manifest at multiple granularities. In this work, we introduce a novel benchmark dataset for anomaly detection in the maritime domain, extending the Open Maritime Traffic Analysis Dataset (OMTAD) into a benchmark tailored for graph-based anomaly detection. Our dataset enables systematic evaluation across three different granularities: node-level, edge-level, and graph-level anomalies. We plan to employ two specialized LLM-based agents: \emph{Trajectory Synthesizer} and \emph{Anomaly Injector} to construct richer interaction contexts and generate semantically meaningful anomalies. We expect this benchmark to promote reproducibility and to foster methodological advances in anomaly detection for non-grid spatio-temporal systems.