Analog vs. Digital Documentation – Cutting the Costs, Expanding the Possibilities. Idjoš Gradište Case Study

Abstract

The article deals with the use of an integrated GIsand image-based modelling approach to archaeological field documentation, developed for the Borderlands: ArISE project. The project, established in 2014, examines social boundaries and interactions from the early Neolithic to the early Iron Age period in the north-east Banat region of modern Serbia. Archaeological excavations at the site of Gradište near Idjoš are at the core of the project, aimed at providing insight into the development of social identities and the manner of coexistence and interactions between different communities of various periods. Due to limited funds, the process of field documentation has been almost completely digitized, enabling fast but very precise documenting of features and finds recovered from the field: increasing the possibilities for post ex analysis, publication and presentation. IANSA 2017 ● VIII/2 ● 125–136 Miroslav Marić, Jugoslav Pendić: Analog vs. Digital Documentation – Cutting the Costs, Expanding the Possibilities. Idjoš Gradište Case Study 126 later, the site was excavated by Miodrag Grbić (Grbić 1950) who, in the course of two excavation campaigns (Grbić 1951) excavated more than 300 m2 inside the circular enclosure searching for the Slavic city. In 1954, Luka Nadlački from the Kikinda Museum excavated on the tell part of the site, and discovered a wattle and daub structure in trench 3 with the remains of pottery attributed to both the Tisza and Vinča style in the same context (Girić 1957, 221–222). Almost two decades later, during 1972, a smallscale rescue archaeological excavation was undertaken at the site by the National Museum Kikinda and provincial Institute for protection of cultural Monuments petrovaradin, with 4 trenches excavated on the Neolithic settlement and others placed over a Bronze Age/Iron Age necropolis located to the southeast of the sub-oval enclosure (Medović 1984). Finally, after a four-decade long hiatus, a new research cycle was instigated in 2014, aimed at researching the Gradište site through a new, broader paradigm (The Borderlands: ARIse project, i.e. Archaeological Research of Iđoš site and its environment). The project is envisioned as an ongoing programme to be undertaken in several stages, including evaluation of the archaeological potential of the site, targeted excavations of defined features, and broader research leading to systematic publication and public outreach. The project is focused, among other aspects, on establishing the exact character of the settlements in the distinct periods of prehistory: to better understand the site’s formation and its prehistoric landscape conditions, and thus to better study and understand the life of the site and its inhabitants. 2. Methodology Immediately from the beginning of the new excavations in 2014 it became clear that available funds could not facilitate having a large excavation crew with various specialists and sub-specialists waiting on standby during the excavation season. Rather, it was decided to expedite the excavation process through a simplification of excavation recording procedures. Given their cost and time-pressure, contemporary archaeological excavations require efficient and exact documentation during all fieldwork and there is thus a strong incentive for excavators to develop new techniques and methods, or refine the existing practices, for a more streamlined approach to field research. Some commercially-available software solutions, coupled with precise instrumentation used in the field, make new digital documentation techniques affordable and easily available alternatives for field research. Although digital archaeological documentation may still be regarded as a novelty, and has many potential limitations (e.g. Zubrow 2006), these obstacles are steadily disappearing with every new data acquisition technique and software package that appears on the market (e.g. Avern, Franssens 2011; Düffort et al. 2011; Motz, carrier 2013; smeets et al. 2013). The number of software solutions available is increasing exponentially, and it is perhaps only a matter of time before even tailor-made digital recording solutions for archaeological excavations become standard tools in the field (some solutions like ArcheocAD, although present for a long while did not Figure 1. The location of the site of Idjoš Gradište. IANSA 2017 ● VIII/2 ● 125–136 Miroslav Marić, Jugoslav Pendić: Analog vs. Digital Documentation – Cutting the Costs, Expanding the Possibilities. Idjoš Gradište Case Study 127 become standard in digital archaeological documentation for various reasons which go beyond the scope of this paper). In order to make the collection, storage and processing of archaeological data recorded in the field as computer and user-friendly as possible, the team opted for a commercial GIs package instead of an open source variant, but the growing number of open source solutions (products such as the long-existing Grass GIs are now being complemented by similar software like QGIs, sAGA GIs and other lessknown programs) are rapidly bringing the same level of confidence and usability to the market and could potentially lead to a complete rejection of the commercial products in the near future, due to their high cost of purchase and upgrades. Using a Harris (1989) matrix system to record the relative stratigraphy of archaeological trenches in the field, made it possible to define a series of polygons representing the outlines of features recorded while being excavated. These polygons were recorded before the excavations using a total station in the field and represent a simplified shape of the detected features. Along these geometric primitives, point data, representing individual finds, samples and other points of interest were recorded in the process, making up two of the three vector shapes any GIs software can interpret and represent. The recorded data was then organized into separate layers that could be combined to produce new, interpretative layers for spatial and statistical analysis of archaeological features (Figure 2). each excavation season was kept separate to enable individual research per year, but features excavated over two or more seasons can also be examined jointly, either through combining data from different layers, or through the direct search capabilities of the software. However, more complex situations in the field, that would have traditionally required an illustrator as part of the team, were treated differently. Well defined surfaces or structures were carefully excavated and cleared until a clear, in situ situation could be established. Then, instead of having a dedicated field illustrator draw a scale drawing, a process which can sometimes take several hours and completely block further excavation in the trench until finished, image-based modelling was used to create indirect documentation in the form of an orthogonal composite model. The resulting model then becomes a baseline for the creation of a drawing offsite after the excavation. Although this method is significantly faster, it is no less precise; in fact just the opposite, it is even more precise. Hand drawing is commonly based on a limited set of measurements followed by a free hand drawing of features in between the measurements by the illustrator. some bias, or random data, is thus unavoidably input into hand drawings of even the best illustrators. Also, it is often the case that the illustrator and the excavator interpret archaeological importance differently, which can lead to some potentially-valuable information being omitted from the hand drawing (Gutehall 2016). Further, the scanning and digitization of scanned drawings can also introduce further errors or omissions into the documentation, either due to equipment or operator. Using a 3D model as a baseline for the drawing of vector shapes is not the end product of this approach, but rather, just a step in the longer process towards obtaining a 3D surface model created through the use of specialised software such as Agisoft photoscan, with a relatively user-friendly interface that enables the low-cost creation of accurate 3D models from a set of digital photographs taken in a particular manner. Figure 2. GIS-based documentation system used by the Borderlands: ARISE system. 0 500 m IANSA 2017 ● VIII/2 ● 125–136 Miroslav Marić, Jugoslav Pendić: Analog vs. Digital Documentation – Cutting the Costs, Expanding the Possibilities. Idjoš Gradište Case Study 128 In contrast to producing 2D documentation out of 3D content (which was in essence a standard procedure even before image-based modelling became available), an argument can be made to shift the whole process completely to 3D space. The model generated through image-based modelling is a single entity, one that is made out of particularities – daub floor surface, pottery fragments, dispersed daub, postholes, daub enclosures, etc. In other words, the remains of a once functional feature; a Neolithic household in this case, are distributed as single entities that have been joined to an unclassified whole. As Wulff and Koch (2011) suggest, it is possible to use polygons (cAD utilities) collected by total station measurements, which are routinely collected during the primary documentation process, as a means to produce a classified model where each class is representing a defined feature. Additionally, using the very same polygons, one can separate the mesh into geometrically-independent units, with the special notion that should be used by a uniform projection system for data collection. However, in some countries, serbia being one example, this kind of archaeological documentation is still not recognised by the authorities (i.e. the Ministries of culture or other similar bodies tasked with overseeing archaeological research) as officially-required documentation, thus rendering it unusable in post excavation reporting. It is our hope that this will change in