Terrestrial-Aerial-SfM and TLS data fusion for agricultural terrace surveys in complex topographic and land cover conditions

• DOI: 10.5194/egusphere-egu2020-3459
• Publication Date: 2020-03-09T14:34:22Z
• Authors: Sara Cucchiaro; Daniel J. Fallu; He Zhang; Kevin Walsh; Kristof Van Oost; Antony G. Brown; Paolo Tarolli
• Keywords: Terrace (agriculture); Land Cover; Aerial Survey; Structure from Motion

<p>In the last two decades, important developments in High-Resolution Topographic (HRT) techniques, methods, sensors, and platforms has greatly improved our ability opportunities for characterization of landscapes through sub-metric DTMs (Digital Terrain Models). The choice most appropriate platform HRT surveys must consider required resolution, spatial extent, features present analysed area. In complex topography, inaccessible areas vegetated environments, use a single technique is constrained by several factors. Therefore, data fusion from different acquisition can be useful solution if we design workflows survey planning, acquisition, post-processing, uncertainty assessment. We tested this approach production detailed ancient agricultural terracing on sites, Soave (North-east Italy) Martelberg Saint-Martens-Voeren (East Belgium); case study sites TerrACE archaeological research project (ERC-2017-ADG: 787790, 2018-2023; https://www.terrace.no/). Both presented topographic landcover conditions: presence vegetation (common ancient, often abandoned, terraces) that cover parts sub-vertical surfaces (e.g., vertical walls terraces), steep slopes large areas. carefully designed techniques order to overcome all these constraints thereby represent 3D-views sites. An integrated employing ground-based UAV Structure Motion (SfM) photogrammetry was used preserve fine-grained detail (via photos) capture flat terrace zones at scale images); while terrestrial Laser Scanner (TLS) permitted accurate highly walls. create point-cloud fusion, key aspect consideration when planning location distribution Ground Control Points (GCPs) SfM TLS targets. These are essential georeferencing co-registering aggregate during final merge. studied areas, where impossible locate GCPs, direct images with differential GNSS, such as PPK (post-processing kinematic). SfM-TLS technologies allowed us accurately recognize entire This point-clouds merge obtain without post-processing steps co-registration process analysis. Even studies highlight how correctly data, it not addressed workflows. study, demonstrated were fundamental phases obtained proper reliable DTMs. high-resolution provided high level landscape extract valuable information about complexes: morphological features, profiles, sections scaled plans, simplifying speeding archaeologist's field laboratory work.</p>