Global Digital Elevation Models in Coastal Area Analyses

This paper provides an overview of global digital elevation models (DEMs) with a special focus on their applicability in coastal areas, particularly in the context of coastal flooding risk assessments. For the pilot area of Kaštela Bay, an elevation contour of 1.5 m above sea level was derived from various global DEMs and compared against a higher-accuracy reference contour derived from a national large-scale LiDAR dataset. In low-lying areas, specifically the mouth of the Jadro River, the 1.5 m elevation contour was additionally identified through conventional land surveying. The comparison highlights differences in the spatial representation of low-lying areas, demonstrating how identical elevation thresholds can result in markedly different spatial patterns depending on the data source. This analysis demonstrates the potential of global DEMs for large-scale analyses and examines their limitations when applied to low-relief coastal environments.