Comprehensive Workflow for Erosion Monitoring of Coastal Archaeological Sites by Means of Digital Photogrammetry: an Iberian Case Study

In keeping with the debate of the effects of climate change and human pressure on cultural heritage, research on archaeological sites that are threatened by erosion—and eventually subject to complete destruction—has increased in the last decade. Different solutions have been proposed at the national and international levels for the study and management of this cultural heritage sites across the globe. Since 2006, an international team of French and Spanish researchers has been working together in the research, monitoring and management of coastal archaeological sites in different Western European regions and in the French West Indies. As a result, several methods and approaches have been developed and implemented. Among those methods, 3D photogrammetric recordings of archaeological sites that are at risk. In this paper, we focus on the methodological aspects of photogrammetric erosion monitoring analysis, taking as an example one case study from NW Iberia: Guidoiro Areoso megalithic monument M3 (Galicia, Spain). Four photogrammetric models were to account for short (6-month to 1-year intervals) and long (10-year intervals) erosion monitoring. The results show the complexity of the local erosion/accretion conditions. The workflow uses free and/or low-cost software and is easy to extrapolate to different sites, regions and archaeological and geographical contexts.