Figure 3: An aerial view distinguishes the Iron Age broch among other remains at Jarlshof. Image © Kieran Baxter (CC BY-NC-ND 3.0)
While the project was part of a research process and experimental in nature, it was designed for a platform where it would be seen by visitors and prospective visitors to the site, such as the Historic Scotland Museum where the outcome is now displayed. This required a deliverable that would work in conjunction with the site as it is found today. To achieve this, the outcome would be designed to relate to the visitor's experience of the site as far as possible. This was intended in both a practical sense (the outcome should function as a tool for orientation on site) and also in terms of the sensory experience that the site invokes. In order that the outcome would remain relatable to the visitor's experience, the interpretative content did not extend to an immersive reconstruction of the past, which would depart entirely from the site's current state. While it would be valuable to see a more detailed reconstruction of the human habitation at Jarlshof, or of changes in the surrounding landscape, this was beyond the scope of this project's objectives.
The intended audience was primarily the lay person who had either visited the site recently or intended to visit in the near future. While this could be extended to the visitor who was unable to travel to the site, remote access was not the main focus of the project. With this target audience in mind, the project design was orientated around the question of what a different perspective on the recognisable remains at Jarlshof could afford to the public interpretation of the site. The development of the resulting project design will be introduced here, along with the narrative theme that was adopted to help communicate the site's complex chronology.
'Nowhere else can such a succession of villages be examined illustrating the everyday life of the inhabitants from Bronze Age to Viking and Mediaeval times.' (Hamilton 1956, 3)
The complex chronology at Jarlshof is difficult to distinguish from first appearances, making it a challenge for public interpretation. The visitor must separate an almost continuous string of settlement remains stretching into prehistory. These include Late Neolithic, Bronze Age, Iron Age, Norse and medieval structures, as well as the 17th-century Laird's House that overlays parts of the earlier phases. While wind-blown sand has provided a good level of preservation across the site, the tightly packed jumble of structures makes for confusing boundaries between phases that are chronologically remote.
From the air, however, parts of the site's narrative become strikingly clear. The distinct phases and changes in architecture can be made out along with the graphic results of coastal erosion, aspects that are visually confused from ground level (Figure 2). The remains of the Iron Age broch is particularly hard to distinguish as it is obscured by later structures and has been in part destroyed by the encroaching coastline. Even without the aid of reconstructed elements, the elevated view immediately separates out these elements revealing, for example, the arc made by the remnants of the broch wall (Figure 3). As such, the site was well suited to an interpretation that made extensive use of aerial imagery of the visible remains.
Jarlshof was discovered in 1897 after storm damage collapsed part of the coastline (Hamilton 1956, 7). The site was subject to a series of fairly exhaustive excavations starting in 1925, when it passed into the care of the Ministry of Works. The results of these were compiled and published by J.R.C. Hamilton in 1956.
Hamilton describes dating the early settlement as 'extremely difficult' (1956, 3) and, while the sequencing for each phase of the site is fairly well established, few absolute dates are known as excavations occurred prior to techniques such as radiocarbon dating. Zuk et al. (2005) highlight the importance of representing 'temporal uncertainty' in visualisation and discuss some useful ways to demonstrate this visually when moving along an interactive timeline. Owing to the breadth of uncertainty in the dating of each phase at Jarlshof, mapping the chronology across a continuous timeline in this way would be unsuitable. Instead, an approach was taken whereby a series of temporal 'cross-sections' were selected; static snapshots around which speculative reconstructions could be based.
These reconstructed snapshots would be superimposed among the remains of other structures dating from before and after the 'cross-sections' in order to aid visitor orientation. The Laird's House for example, while among the more recent structures, is a key part of the site's visual profile. If the later structures were missing from the early reconstructed sequences, the viewer would be less able to contextualise the reconstructed elements within the visible present-day site.
Superimposing lost structures into a present-day space may serve to enhance public engagement with the past (Vergauwen et al. 2004). While Jarlshof was a suitable subject to demonstrate this spatial continuity, the problems of applying a conventional timeline called for a different approach to representing time in the visualisation. To this end, a narrative theme was developed that tied together the site's overall story.
There has been an increasing interest in the role of human experience in the archaeology of British prehistory (Brück 2005). While it is not suggested that this visualisation, or any other mode of representation, could emulate an embodied, and personalised, experience of visiting an ancient monument, an effort was made to incorporate sensory elements that extend beyond the structure of the site. These included aspects of weather and lighting conditions drawn directly from fieldwork.
The narrative theme of 'four thousand years in one day' was designed to represent the timeframe of Jarlshof in a way that relates to the broad story of human habitation at the site. The animated outcome would follow the course of a day, roughly correlated to the course of human settlement at the site. The earliest settlement would be represented at dawn while the Laird's House, likely to be the last permanent habitation on the site, would appear towards the end of the day. This theme would incorporate a range of lighting and weather while helping the viewer to conceptualise the story of the site as a whole. It was hoped that the change in conditions would give the impression of a fleeting sequence of events rather than a static, digital environment.