Digital Photogrammetry applied to Archaeology

Underwater photogrammetry in archaeology in Egypt is a completely new experience applied for the first time on the submerged archaeological site of the lighthouse of Alexandria situated on the eastern extremity of the ancient island of Pharos at the foot of Qaitbay Fort at a depth of 2 to 9 metres. In 2009/2010, the CEAlex launched a 3D photogrammetry data-gathering programme for the virtual reassembly of broken artefacts. In 2013 and the beginning of 2014, with the support of the Honor Frost Foundation, methods were developed and refined to acquire manual photographic data of the entire underwater site of Qaitbay using a DSLR camera, simple and low cost materials to obtain a digital surface model (DSM) of the submerged site of the lighthouse, and also to create 3D models of the objects themselves, such as statues, bases of statues and architectural elements. In this paper we present the methodology used for underwater data acquisition, data processing and modelling in order to generate a DSM of the submerged site of Alexandria's ancient lighthouse. Until 2016, only about 7200 m 2 of the submerged site, which exceeds more than 13000 m 2 , was covered. One of our main objectives in this project is to georeference the site since this would allow for a very precise 3D model and for correcting the orientation of the site as regards the real-world space.

The 'digital turn' in archaeology has resulted in documentation, analysis, visualization and repository requirements becoming increasingly digital in recent years. However, we are only at the beginning of understanding how the shift from analogue to digital affects archaeological interpretation, as attention has mainly been directed towards technological aspects. However, how archaeology is executed influences the production of archaeological knowledge , and additional research into digital practices and their consequences is needed. During the latest excavation in 2014 of the Neolithic flint mines of Södra Sallerup, in Malmö in southern Sweden, several recording methods were used to document the remains in plan, including hand drawing, digital mapping with GPS and digital photography using a camera mounted on a pole. The records were used to create both digital plans and georeferenced orthophotos from a 3D model and from photomosaic. The aim was to produce a record comparable to previous documentation from decades of archaeological excavations of the flint mines in the area, as well as one that is up-to-date with today's digital standards. The methods are described and their consequences for the archaeological results are discussed.

Photogrammetry provides an accessible, cost-effective means of creating a high-resolution, digital 3D record of archaeological artefacts. The methodology has been widely adopted, but a number of issues remain, especially in relation to model variability, and to misalignments that result in gaps in the models generated. Two new approaches are presented here that have been shown to increase standardisation during data capture and processing routines. This ensures that models are seamless and quantitatively accurate.

Abstract: This chapter (written in Spanish) provides a general characterization of the garments with beads documented in the Montelirio tholos, including considerations of their manufacture and use in mortuary practices. Firstly, the contexts in which the beads were found, the position and distribution of the latter, also in association with specific individuals, are described with attention to the post-depositional processes that affected the formation of the archaeological deposits. Secondly, the techniques of bead manufacture and assemblage deployed to create elaborate garments, as well as the characteristics of the latter, are examined in light of the evidence provided by the beads, their location, and distribution. The chapter concludes with some preliminary thoughts on the social dimension of the manufacture of such elaborate garments with beads, which most probably required organized craftsmanship, and their use in the mortuary practices developed in the Montelirio tholos.

This report presents the results of a comprehensive documentation and analysis of ground stone bedrock features at LA 43414 (the Merchant site) and LA 121668. The bedrock features are located on lands administered by the Carlsbad Field Office (CFO) of the Bureau of Land Management and the New Mexico State Land Office. This project was funded under the Permian Basin Programmatic Agreement (PBPA) administered by the CFO. This investigation recorded and examined 359 ground stone bedrock features between the two sites, using newly standardized documentation procedures for bedrock mortars and grinding basins that were instigated by the CFO (see Murrell 2019). Structure from Motion photogrammetry was used to make high-resolution 3D models of the features, which also provided the data to gather length, width, and depth data for each feature. Additionally, qualitative attributes were recorded during on-site field work. A statistical cluster analysis was used to evaluate the morphological variation of the bedrock features and subsequently to identify six clusters or groups or similar features. The resulting clusters assessed in relation to a suite of related research topics including (1) exploring the functional and morphological variability of bedrock features; (2) correlating use-wear characteristics to potential function; (3) discussing the spatial distribution of bedrock feature morphologies and their relation to other features such as burned rock accumulations or pueblo remains; (4) examining whether the bedrock features were created through intentional manufacture or sustained use; (5) discussing the use-life of features; (6) determining the potential age and cultural affiliation of the bedrock features; (7) correlating the associated past and present plant and mineral resources using previous excavation data at LA 43414, ethnography, and pollen results; and (8) evaluating the possibility of ritual contexts for bedrock features at these sites.

This paper presents new developments on drone‐based automated survey for the detection of individual items or fragments of material culture visible on the ground surface. Since the publication of our original proof of concept, awarded with the Journal of Archaeological Science and Society for Archaeological Sciences Emerging Investigator Award 2019, additional funding has allowed us to implement a series of improvements to the method. These aim to improve detection capabilities and the extraction of items' shapes and increase flight autonomy, control, area covered per flight and the type of environments in which the method can be applied while reducing computing needs, processing time and expertise necessary for its application. This paper provides an account of the methods followed to achieve these objectives, their preliminary results and the current development for their implementation into a free and open‐source system that can be used by the archaeological community at large.

In the last few years SfM  has taken on a more important part in the research and documentation of archaeological sites. The benefits of 3D documentation are manifold: areas and contexts can be recorded quickly, true to scale and transformed into a 3D model.
In this article a workflow is presented which allows to document archaeological profiles with SfM efficiently and in high resolution so true to scale digital drawings can be created.

The aim of this paper is to compare the tracing made at the Bronze Age petroglyph of “Barreira” in Verdoejo (Portugal) (Novoa and Costas 2004) with two different and new methodologies based on photogrammetry. This technique is oriented to reduce the different problems of subjectivity that are present in the old systems of registry, and furthermore it allows studying the rock surface without touching it.
These techniques are:
• The Virtual RTI proposed as an alternative to normal RTI method, which is a combination of reflectance transformation techniques with photogrammetry and non-contact digitising. It uses animated virtual domes, leading to a sequence of renderings of the 3D model, processed using the same methods as normal RTIs. The virtual RTI provides an advanced level of interaction with the 3D model and enhanced visualization of the surface topography (Earl, Beale, Martinez and Pagi 2010).
• Radiance Scaling is a shader applied to 3D models, which adjusts reflected light intensities in a way dependent on both surface curvature and material characteristics. As a result, diffuse shading or highlight variations become correlated to surface feature variations, enhancing surface concavities and convexities (Vergne, Pacanowski, Barla, Granier and Schilck 2010).

Este artigo aborda as experiências dos autores com a integração de ferramentas digitais à pesquisa e interpretação de sítios arqueológicos de naufrágios históricos. Para isso apresentamos um fluxo de trabalho que tem como base o uso da fotogrametria para a criação de modelos digitais tridimensionais em escala real de sítios e artefatos, que se articula nas diversas etapas metodológicas com vistas a interpretação dos sítios e a reconstrução arqueológica dos navios estudados. Os resultados são discutidos em termos do impacto da virtualização do dado arqueológico na prática acadêmica, particularmente nos aspectos de coleta, armazenamento, análise, interpretação e disseminação do conhecimento.

LA SCOPERTA Nell'estate 2009, a c. 500 m a nord-est della costa di Acireale, ai confini tra i comuni di Aci Castello e Acireale (Catania), nello spec-chio di mare antistante Capo Mulini (figura 1), Giancarlo Camaggi e Giuseppe Tomasello scoprivano un cumulo di anfore. La segnala-zione alla Soprintendenza fu seguita da una prima ricognizione nel giugno 2010 (Tisseyre 2010) ma, a causa delle condizioni particolari del giacimento del sito-profondità, correnti, lontananza della costa-, una prima vera cam-pagna approfondita fu realizzata solo nel 2016. Si è provveduto a operare su tre direzioni: una prima campagna di rilievi fotografici in due immersioni, al fine di ottenere un rilievo foto-grammetrico completo del sito, una verifica con un robot sottomarino (Remotely Operated Vehicle-ROV) del Nucleo sommozzatori della Guardia Costiera di Messina, comandante Giuseppe Simeone, effettuata fino a 90 m di profondità e su un raggio di 100 m intorno al relitto e infine un'operazione di recupero di reperti già rilevati fuori del cumulo principale, a scopo diagnostico. Le immersioni si sono svolte nei mesi di luglio e fine agosto 2016: si tratta dunque di presentare qui le osservazioni preliminari. Tutte le conclu-sioni sono per lo più parziali e saranno oggetto di complemento d'indagine. [PT] IL TERRITORIO E IL CONTESTO DEL NAUFRAGIO La zona di rinvenimento del relitto s'inserisce in un ben più ampio contesto di ritrovamen-ti archeologici che evidenziano l'importanza storica della città di Catania in età antica e l'intensità dei traffici commerciali marittimi che in ogni epoca hanno caratterizzato questo tratto di costa siciliana. Nella fattispecie lo scalo di Capo Mulini, a sud del relitto, fu oggetto, tra il 1995 e il 2001, di una sistematica ricognizione archeologica effettuata dall'Università degli Studi di Catania, a cura della cattedra di Topografia antica della Facoltà di Lettere, presieduta dal professor Edoardo Tortorici (Tortorici 2002). L'esito di suddette analisi consentì di identifica-re, nei fondali del golfo in oggetto, un'ingente mole di ritrovamenti coerenti, dal punto di vista cronologico e tipologico, con i materiali rinve-nuti nei livelli di occupazione della terraferma, a conferma di quanto già noto dalle fonti a partire dal XVI-XVII secolo in merito al riconoscimento di un insediamento costiero di grande interesse sviluppatosi, senza soluzione di continuità, dall'età preistorica ai nostri giorni. Prossimo a quest'ultimo in direzione sud è l'altro importante scalo di Aci Castello e il piccolo approdo di Punta Aguzza, individuato nel 2012, che ha consentito di portare alla luce un'ingente mole di materiale. Qui, tra il 2012 e il 2016, oltre a 4 anfore di tipo Corinzio A e B ritenute appartenenti a un relitto del VI a.C (Tis-seyre 2010), in aree e a batimetrie eterogenee, sono stati scoperti molti altri reperti di epoche differenti: un dolium frammentario, contenitori da trasporto di epoca romana e bizantina, un numero imprecisato di ancore 'a gravità' litiche e in ferro del tipo 'a presa' e in piombo, nonché varie attrezzature di bordo, testimoni imperituri di una continuata attività antropica all'interno della baia (in fase di pubblicazione). I materiali recuperati in località Punta Aguzza rientrano