3D GIS for building archeology – Combining old and new data in a three-dimensional information system in the case study of Lund Cathedral

Traditionally, building archeology is conducted by creating and interpreting 2D documentation, even though the spatial properties of a building are not fully expressed in 2D. The reason for neglecting the third dimension has been mostly due to technical limitations in data acquisition and creation, as well as visualization. The fast progress in 3D technology puts an end to those limitations even though its full potential is still yet to be explored. This study shows how a 3D GIS can be applied from the outset of a building archaeological study to create a three-dimensional information system connected to a geometrically accurate 3D model of a structure. The case study investigates Lund Cathedral (Sweden) and is linked to a larger research project launched in occasion of the cathedral’s 900th anniversary in 2023 (“Lund Cathedral 2023”). Within the framework of this project, the cathedral was acquired digitally through laser scanning and photogrammetry. The building is characterized by a complex building history with a multitude of changes and renovations. Gaining an understanding of all interventions, as well as managing the different types of datasets created during two centuries of study is a challenge. In order to overcome these difficulties, various datasets (from excavations, wall analyses, georadar, etc.) and their relevant metadata were imported into the ArcGIS software and linked to a geometrically accurate 3D model of the church, placing all pieces of information in their correct spatial position. Thus, data that was previously impossible to view simultaneously and in the same space can be displayed together, creating a unique holistic oversight of the available material. Through the flexibility and versatility of the system, information can be displayed and queried at will, as well as updated continuously, greatly facilitating interpretation and making it an important resource throughout the entire building archaeological stud

3D GIS for the visualization and analysis of archaeological data

Archaeologists deal with very inhomogeneous data that includes qualitative and quantitative, spatial and non-spatial data. A Geographical Information System (GIS) offers a way to manage, visualize and analyze complex data. Working with a 3D GIS allows to restore the third dimension to previously flattened 2D information such as maps and drawings, while at the same time enabling more complex analysis about volume or visual perception

Resolution and quality issues in 3D analysis of inscribed signs : an example from Cypro-Minoan inscriptions

A recurrent demand in many archaeological digital documentation systems is the need for an accurate as possible registration of data. Somehow, contrary to this request, are efforts led by various computer science groups dealing with 3D documentation and focusing on developing fast and cheap solutions to record 3D models of archaeological assets. The aim of the article is to highlight the importance of aligning the 3D documentation strategy to the archaeological aims, by detailing all factors to be considered when deciding on one documentation strategy over another. The archaeological question discussed here, part of the PhD thesis of one of the co-authors (MP), relates to the Cypro-Minoan signatory and its diachronic variability. The 3D geometric characterization of signs and subsequent shape analysis is the method chosen to reach this goal. A major effort to be invested in correctly determining the shape and variability of each sign, is in assuring that the 3D captured shape is as close as possible to the archaeological reality, which is a common problem not only in palaeographical analysis but also in other fields, where features of interest are in the sub-millimetre range. The paper will illustrate how different data acquisition approaches and post-processing steps such as alignment methods and error treatment may distort the visualised result and thus have a negative impact on planned analysis. Thus, it will argue for the importance of more detailed paradata to allow an informed assessment of the reliability of 3D models and it proposes a list of values and decision-making steps that help make the 3D digitization process more robust and verifiable

Assessing visual perception in heritage sites with visual acuity : case study of the cathedral of St. John the Theologian in Nicosia, Cyprus

A challenging aspect of visibility studies is visual acuity, which concerns the clarity of vision within a given space in relation to variables such as spatial geometry, lighting conditions, the physical properties of the viewed object, or the familiarity of viewers with the target. Our research proposes a novel approach to visibility studies, based on visual acuity and its related pipeline, which integrates qualitative and quantitative aspects such as the cultural background of viewers, the illumination values of space, contrast, and size of objects of interest as well as their meaning and context. The proposed pipeline relies on 3D documentation of the investigated space, light measurements, research in optics, trigonometry calculations, and 3D GIS set against images and architectural space. The method's effectiveness is demonstrated in the study of the iconography of the Cathedral of St. John the Theologian in Nicosia, Cyprus, the work hypothesis being that the church's spatial organization, choice of scenes, and level of detail were carefully planned to establish visual narratives with strong political and religious connotations and to overall dictate the ways the building was accessed and experienced. The method can be broadly applied for visibility analyses in a variety of case-studies in closed spaces

A 3D chaine opératoire approach to the study of Late Bronze Age cylinder seals : a case study from Hala Sultan Tekke, Cyprus

The aim of this paper is to explore the potential of high-resolution 3D documentation and sub- sequent scientific visualization and surface analysis for the study of cylinder seals. The material comes from the ongoing Swedish excavations at Hala Sultan Tekke, which is located on the south-east coast of Cyprus and functioned as one of the most important trade centres of the eastern Mediterranean in the Late Bronze Age (c. 1650-1150 BCE). The traditional way of documenting cylinder seals includes photographs and drawings of the seal itself and its impression on semi-hard material. Thus, the material available for second-source investigation is conditioned by the quality of the photo and technical details on how the image was acquired, whereas drawings are subjected to the interpretation of the draughtsperson. Therefore, we have decided to adopt a high-accuracy 3D approach to the documentation of seals, which allows a through- out geometric investigation of their surface. This will help to identify and characterize aspects related to production techniques and modes of manufacture, as well as their possible use

An integrated 3D shape analysis and scientific visualization approach to the study of a Late Bronze Age unique stone object from Pyla-Kokkinokremos, Cyprus

Multiple analyses of a strange object from the Pyla Excavation

An integrated 3D shape analysis and scientific visualization approach to the study of a Late Bronze Age unique stone object from Pyla-Kokkinokremos, Cyprus

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