Being able to examine objects, sites and buildings three-dimensionally is a crucial element in interpreting many, if not most, heritage assets. This is reflected in modern heritage survey and recording techniques like topographical surveying, ground-based and/or airborne laser scanning of objects, sites and buildings, or three- dimensional geophysical survey methods (e.g., GPR), which are increasingly being used in archaeological fieldwork. Many of these methods have, however, only become widely available over the past decade. Before that, archaeological fieldwork, whether excavation, landscape, or building survey, relied mostly on 2D techniques to record the three- dimensionality of heritage assets; like plan, elevation and section drawings, and 2D photographs.
Modern photogrammetric software solutions allow automated 3D rendering of objects from several 2D pictures taken of the object at random angles and distances. Using such solutions to create 3D renderings of excavation trenches and other objects has been successfully tested in the past few years.
While such software solutions have successfully been applied to current archaeological excavations and surveys, they have not yet been tried on archival photographs. Naturally, before such software solutions have become available, photographs were not taken with the possibility of later using them for 3D rendering in mind. However, it has been standard practice in archaeology to take several pictures of relevant objects, features, sites and monuments for a long time. Thus, the possibility exists that photographic archives of heritage assets may contain evidence that can be used to re-create the three-dimensionality of lost heritage assets. This applies to the stratification encountered and destroyed during archaeological excavations and to buildings recorded during building surveys and since destroyed or significantly altered. But it also may apply to monuments that were photographed during archaeological surveys or even only field trips and have since been damaged or destroyed, for instance, some standing stones known to have existed in Gwynedd from old photographic records.
The alternative views project aims to recreate the three-dimensionality of lost heritage assets by taking a case- study based approach to a sizeable image database which in parts dates back to the 1970s and (partially) even before. Alongside Gwynedd Archaeological Trust’s (GAT) photographic archive (c. 500,000 photographs) we have access to Bangor University’s archaeological slide collection (c. 70,000 photographs). Images will then be examined visually to identify potential candidates for 3D photogrammetry rendering. Images of sites and monuments that have since been destroyed or significantly altered will be selected as a matter of priority, with a preference for images taken at the same time. This process, however, is further complicated by the fact that these archived images were developed over a long period, and have been created by different technologies. The project aims to investigate the possibility of combining these images into one rendering process, to successfully create a 3D model of a heritage asset.
Thus we aim to re-create 3D images of sites that cannot be digitised into 3D today - re-creating lost heritage.