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Rundbrief Grabungstechnik, Bd. 18 (2020): Rundbrief Grabungstechnik

3D-technologies are increasingly shaping the way archaeologists work and think. The fact that 3D recording techniques are becoming part of the standard toolkit in archaeological fieldwork opens up enormous opportunities for research and public outreach. As archaeological excavations are seen to be destructive, conventional documentation techniques have been shaped over decades if not centuries to mitigate as much information loss as possible. This includes the development of fitting tools and workflows as well as best practices in archaeological data collection, long-term archiving, research and dissemination. As new tools, 3D-Technologies need to be implemented into these existing best practices and workflows. In order to take full advantage of the new possibilities, we consider an integrated approach from the beginning of a project to be essential. This enables the successful implementation of 3D-technologies in all stages: it is not only important during fieldwork, but also later during research or public outreach. There, for instance, challenges concerning interoperability or quality may arise and have to be coped with. Also, the irreversibility of archaeological excavations has to be met with the functioning of long-term archiving of mostly large and complex datasets. Despite the increasing implementation of 3D-technologies in everyday archaeological practice, the overall experience of knowing what decisions to make and how they will affect the later possibilities and limitations is still developing. Nevertheless, there are ever more successful projects showing how 3D-techniques can be fully integrated into archaeological practice. This session aims to bring these examples of integrated research projects to a broader archaeological audience. As these potent documentation techniques have found their way into everyday practice, a broad dissemination and discussion of their possibilities and arising challenges is urgently needed.

Excavating an archaeological site involves many decisions and trade-offs to be made. This is not only due to the limited resources on site but also has methodological roots. As excavations are destructive, decisions on the quantity and on which details documentation should focus must be taken. For documentation, a wide range of tools are available. One such tool is 3D documentation. It brings with it many benefits like the possibility to move in a 3D space through the excavation, the generating of ‘virtual’ profiles, or high precision DEM’s to name a few. 3D documentation of finds offers the possibility of fast unwrapping of complex features, fast drawings from different angles, or printing as a replica for different purposes. However, when compared to conventional methods, more problematic issues arise as well. 3D models must be calculated before the excavation can proceed. The calculation either needs time or powerful hardware. The method also results in a vast amount of data, as, in contrast to a drawing, most details are recorded. The question here is how to balance and evaluate these pros and cons. With this session, we want to ask: How and on which basis do you decide when choosing the documentation method? How do you evaluate the cost and time benefit of 3D documentation, also taking into account consequential costs such as data storage and curation over long periods of time? Is the time saved in the field doubled in the office? How much of the recorded data is used in the evaluation? We aim to bring together archeologists, technicians, and restaurateurs concerned with the above stated questions, whether working in the field or the lab, or as decision-makers in managing positions. We highly encourage members of commercial archaeological enterprises and of heritage offices to bring in their points of view.

The wetland site of Burgäschisee-Nord is located on the northern shore of the small lake Burgäschi in Central Switzerland. It is one of several Neolithic sites located at the lake shore and has been newly excavated between 2015-2017 within the framework of the international and interdiscpiplinary project “Beyond lake villages. Studying Neolithic environmental changes and human impact at small lakes in Switzerland, Germany and Austria”. During the 37th century BC, the site Burgäschisee-Nord is culturally located between two regions each associated with a specific pottery style (eg. Western Switzerland with the so-called Cortaillod style and the region of lake Zurich with the so-called Pfyn style). Both stylistic influences are reflected in the ceramics of the sites at lake Burgäschi, however in Burgäschisee-Nord (3700-3650 calBC) an unexpected quantity of pots is produced in a style related to eastern Central Switzerland (Lake Zurich region). To conduct an in-depth study of these stylistic interrelationships a crossed-analysis was applied, combining stylistic, technological and petrographic methodologies. The technological analysis, based on the reconstruction of the “chaînes opératoires”, shows comparable results to the stylistic study of the material. For example, the surface treatments of pots in Burgäschisee-Nord are close to those identified on pots of settlements around lake Zurich. Nevertheless, the techniques of shaping refer to both the regions of Western Switzerland and Lake Zurich. The petrographic analysis reveals that the analysed ceramics have been produced with local raw materials, without having a relation to stylistic features. The combined approach allows us to draw a more profound picture of the pottery production at lake Burgäschi in the 37th century BC and its entanglements with Western Switzerland and the Lake Zurich region.

Digital archaeology and image-based 3D-documentation have become widespread in archaeological everyday practice. Despite its relevance, a common ground for storing and archiving the massive datasets produced by 3D-documentation is still missing. Aims, applications and strategies are diverse, as are software solutions. To get an insight into the current use and the application of image-based 3Ddocumentation a survey among practitioners was conducted. The survey was spread through brad channels and conducted online. The aim of the survey was to address the following main-questions: - How is image-based 3D-technology used and applied? - What solutions and practices are in use concerning the archiving of 3D-data? - What are the needs for a sustainable and reliable application of 3D-technology? The survey reached more than 70 contributions from a range of different countries from practitioners working with image-based 3D-technology. Preliminary results seem to confirm a broad range of different applications, different programs and different data management approaches.

Zwischen Januar und März 2020 wurde durch die «EAA Community for 3D-Technologies in Archaeology» eine international ausgerichtete Umfrage zur Nutzung von bildbasierten 3D-Technologien durchgeführt. Das Ziel war, einen breiten Einblick in die Anwendung von bildbasierten 3D-Technologien in der Praxis zu erhalten. Die Auswertung der Befragung erlaubt es, den Stellenwert der Methoden und die wichtigsten Anwendungsziele der Anwender*innen herauszuarbeiten. Zudem gibt sie Einblick in die verwendete Software und Dateiformate sowie in die Umsetzung der Archivierung. Damit lassen sich die wesentlichen Herausforderungen für die weitere Entwicklung und fortschreitende Implementation von 3DTechnologien in die Praxis erkennen.

Digital Archaeology and Image-Based 3D-Documentation have become widespread in archaeological everyday practice. Despite its relevance, a common ground for storing and archiving the massive datasets produced by 3D-Documentation is still missing: What needs to be archived? Who needs access to data? What are current solutions? What are long-term challenges? These pressing questions arose during the EAA annual meeting 2019 in Bern and need urgently to be discussed in more detail. This round table will tackle these challenges in an interdisciplinary discussion with participants not only from the archaeological field, but also from digital archives and other institutions dealing with long-term data storage. The aim is to clarify the following points: - the needs for the storage of 3D-related data like reproducibility and compatibility - the challenges of archiving (data amount, data format, access, digital long-term storage) - current available solutions focusing on 3D-data Part of the discussion will draw from a survey on the needs and current solutions in European archaeology. The survey will be conducted in the first half of the year 2020. The planned outcome of this interdisciplinary round table is a joint publication on these 3 topics. We invite researchers of all disciplines that are working with Imaged-Based 3D-Documentation, who have encountered one of these topics and are willing to contribute their experience and knowledge to take 3D-Documentation to the next level.

For a pilot study carried out by the University of Bern together with local partners in Summer 2018 at the pile-dwelling site Bay of Bones (Rep. of Macedonia), a new workflow for underwater pile-field documentation was developed. The site lies in shallow water of 3–5 meters depth and the most obvious constructive remains of the prehistoric settlement are thousands of wooden piles. The piles, mainly of oak and juniper, are excellently preserved in the lake sediments. The aim of the project was to document and sample 40 m2 surface area of the pile-field and the dendrochronological analysis of the samples. Dendrochronological sampling requires cutting the top-ends of the piles and thus changes the preserved situation. Therefore beforehand documentation must ensure the localization of each pile on a map. This calls for a method that ensures a) that every pile is distinctly labeled and b) the location of each pile is accurately captured. While on land, this can easily be achieved, underwater working conditions complicate common procedures. E.g. by measuring with a folding ruler from a local grid, there is later no way to evaluate measuring mistakes or the internal error of the local grid. In addition, for unpracticed divers measuring by hand underwater is not only time-consuming but also tends a lot more to erroneous results than on land. The goal was therefore to find a time-saving, accurate and easy to carry out way to locate the positions of several hundred piles in shallow water. The best solution for us to achieve these goals was a new standardized and reproducible workflow with Structure from Motion (SfM). The applied approach for underwater SfM-documentation includes on-site workflow and post-processing. The on-site workflow covers all steps from the preparation of the archaeological structures to the photographic data acquisition, the calculation of a preliminary 3D-model and its on-site verification. The crucial step was to ensure the suitability for modeling of the data before the situation underwater was irreversibly changed through sampling. Post-processing was carried out in Adobe Photoshop, Agisoft PhotoScan and QGIS where the data was optimized in quality and standardized from digital image processing to the construction of a georeferenced orthomosaic. Applying these results, we can later visualize patterns in the spatial distribution of the piles concerning e.g. their age, their size or their wood species. This will lead to answers regarding architecture, internal chronology, and in-site settlement dynamics. With this newly standardized two-step-workflow for underwater structure documentation, we are able to asses and compare the quality of each orthomosaic in a reproducible way. The presented method is highly promising for underwater-documentation of prehistoric pile-fields, yielding accurate digital plans in an efficient and cost-saving way.

The archaeological campaign in 2018 at the site Plocha-Miciov Grad near Gradište on the Lake Ohrid gave new insight about this pile-dwelling settlement. The establishment of an international team and the application of the multidisciplinary approach have yielded fruitful research and have enabled a wider scientific perspective for a palafite with a particularly complex chronological and cultural character.

The Ploča-Mikjov Grad site is located on the Lake of Ohrid, in the Bay of Bones near Gradište, in the vicinity of the village of Peštani., Археолошкиот локалитет „Плоча - Миќов Град“ се наоѓа на Охридското Езеро, во Заливот на Коските кај Градиште, во близина на селото Пештани.