Percorrer por autor "Goyanes, Gabriel"
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- Deception Island 1967–1970 volcano eruptions from historical aerial frames and satellite imagery (Antarctic Peninsula)Publication . Prates, Gonçalo; Torrecillas, Cristina; Berrocoso, Manuel; Goyanes, Gabriel; Vieira, GonçaloAerial frames and satellite imagery are widely recognized data sources from which to produce maps. For volcanoes, maps enable the quantification of erupted ash and the destruction caused. The last eruptive sequence on Deception Island was endured from 1967 to 1970. Analogue maps were produced via classical photogrammetric methods with a high degree of human intervention mainly to analyse the volcanic-centres areas only. However, historical aerial frames cover the whole of Deception Island. Structure from motion photogrammetry, a near-automated compilation of digital image processing strategies, minimizes the degree of human intervention to produce orthographic mosaics and digital elevation models from digital aerial frames. Orthographic mosaics were produced from historical aerial frames of 1956 and 1968, and a Kompsat-3 image of 2020. Their shared rootmean-square deviation was 1.8 m and 1.7 m in easting and northing, respectively, at ground control points measured with phase-differential global navigation satellite systems. The digital elevation models were processed with a root-mean-square deviation of 2.3 m and 3.6 m from 1956 and 1968 aerial frames, respectively. As the first application, erupted ashfall and the subsequent destruction, mainly at the former Chilean and British bases, were identified, and the volume of erupted ash was assessed to be over 0.16 km3 within the area mapped by these new digital cartographic products.
- A multi-embankment Chalcolithic walled enclosurePublication . Texugo, André; Basílio, Ana Catarina; Pina, Pedro; Goyanes, Gabriel; Vieira, GonçaloOta, a key part of the Chalcolithic walled enclosure phenomenon in Portuguese Estremadura, represents a unique settlement strategy within the actual territory of Portugal. The architecture and social dynamics of this site remained largely unexplored until 2019. This study marks a significant shift in its study, utilizing a synergistic approach of archaeology and geotechnologies, embodied in the using an Unmanned Aerial Vehicle equipped with LiDAR. This innovative combination successfully pene trated the dense vegetation, revealing 21 previously unknown archaeological features. The re sults from the fieldwork unveiled a novel type of walled enclosure at Ota, characterized by a series of four embankments. This discovery prompts a re-evaluation of the roles and practices of 3rd millennium BC com munities in Portuguese Estremadura. Furthermore, the proven efficacy of this methodology paves the way for its application in similar archaeological contexts. The paper presents a comprehensive analy sis of the recent fieldwork, integrating interpretations from LiDAR data, material studies and 14C dating.