# Modeling of Historical Marine Casualty on S-100 Electronic Navigational Charts
## 6 Conclusions  
This study proposed a data model for representing marine casualty information in accordance with the S-100 framework, addressing a previously unstructured domain within maritime data systems. While recent S-100-based models have primarily focused on real-time navigational safety data, such as warnings and environmental conditions, the model presented in this study is distinguished by its focus on formalizing and visualizing historical casualty records. By doing so, it introduces a foundation for integrating accident data into digital navigational environments in a structured, spatially referenced, and interoperable form. The modeling process involved more than conceptual design--it required the actual development of a complete S-100 data package. This included the definition of a domain-specific application schema, the creation of a machine-readable FC, and the development of a PC specifying the visual representation of casualty data in ECDIS environments. Symbol design was carried out with attention to clarity, consistency, and integration with existing navigational symbology. Each component was carefully aligned with the S-100 GFM and relevant parts of the standard to ensure compliance and interoperability. A case study using 21,539 real marine casualty records demonstrated that the proposed model could be successfully implemented in an S-100-compatible viewing environment. The findings also revealed practical challenges--particularly in terms of symbol congestion in high-density areas and the limitations of point-based representation. Visualization experiments underscored the importance of filtering and generalization strategies to ensure clarity and operational relevance. Furthermore, issues of semantic harmonization across data sources and the need for integration with other S-100 layers were identified as important directions for improvement. The significance of this work lies in its transformation of marine casualty data--from informal, narrative-based documentation--into a standardized format that can be utilized within digital navigational systems. Rather than treating accident data as isolated historical records, this model enables its integration into broader maritime information systems, where it can contribute to risk-aware route planning, incident pattern analysis, and situational awareness. The interoperability of the model also opens avenues for alignment with other safety-related S-100 layers, ensuring consistent portrayal and interaction across applications. To enhance the model's practical applicability, future work will include structured usability evaluations based on ISO/IEC 25023 metrics [35], involving ECDIS operators, VTS officers, and maritime analysts to assess task performance, efficiency, and perceived usability in realistic scenarios. In parallel, applying NLP techniques may support the automated transformation of unstructured casualty reports into model-compliant instances, improving scalability. Taken together, these developments will help establish the proposed model as a practical framework for structuring and visualizing marine casualty data within the S-100 environment. The structured dataset may also support advanced applications such as route optimization, incident trend analysis, and predictive risk assessment--contributing to the broader shift toward standardized, data-driven navigation systems. Conceptualization, S.L. ; methodology, C.L. ; software, H.J. ; validation, C.L. ; formal analysis, C.L. ; investigation, H.J. ; resources, S.L. ; data curation, H.J. ; writing--original draft preparation, H.J. ; writing--review and editing, C.L. ; visualization, H.J. ; supervision, S.L. ; project administration, S.L. All authors have read and agreed to the published version of the manuscript. This research was supported by the Korea Institute of Marine Science & Technology Promotion (KIMSI) funded by the Ministry of Oceans and Fisheries, Republic of Korea (RS-2023-00238653). Informed Consent Statement: Not applicable.