The Zamani Project – Heritage Documentation Beyond the Point Cloud
The world’s tangible cultural heritage is suffering under an onslaught of war, cultural terrorism, vandalism, natural disasters, art theft, neglect and natural deterioration over time. While none of this destruction can be prevented by even the most advanced state-of-the-art digital documentation technology, digital heritage documentation makes a significant contribution to, at least, the virtual preservation of humankind’s past. It also plays a major role in conservation and restoration projects.
Part of the spatial heritage documentation community uses a minimal number of laser scans to document sites in the form of a point clouds and, at best, as a derived meshed surface. In some cases, scans are restricted to the outside of monuments neglecting the existence of inside rooms and features. While, there can be no doubt that a mere laser-scanner-derived point cloud can serve as a valuable record and assist with restoration interventions, it is by no means sufficient for scientifically sound documentation. A holistic approach, with adequate metadata, is required to achieve this.
The Zamani (Swahili for ‘the past’) Heritage Documentation Project based at the University of Cape Town attempts such a holistic approach wherever possible. Site records produced by the group comprised of 3D models of consistent high resolution covering an entire building or monument inside and outside. Elevations, sections, ground plans and roof plans are derived from these models. Texturing was applied infrequently during the early years of the project, but has become standard now. Structure-from-motion photography is employed for texturing and in places inaccessible for laser scanners. 3D landscape models and DTMs of the immediate surroundings of the structures also form part of the site data. Examples of this are Lalibela and the Valley of the Queens in Luxor where large parts of the area surrounding the monuments were scanned with terrestrial scanners and modelled.
Geo-referenced GISs are produced, where suitable, combining RTK-GPS measurements with heads-up digitising of birds-eye views of orthogonally projected and levelled 3D models. Extensive sets of full-dome panoramas combined into panorama tours are also produced (for example, in Petra 400 panoramas were created and combined in six panorama tours). For special applications, such as restoration projects ortho-images of important surfaces are generated from the textured models. Overriding principles adhered to by the Zamani project are maximum objectivity, minimum hole filling, uniform high resolution, high metric accuracy and quality control. The data are structured via metadata for incorporation into databases. The Zamani project is now focussing on publishing interactive spatial data online via Virtual Worlds, which allow a user to virtually explore a site in first person perspective. Individual interactive 3D models are also available presented online.
The Zamani project has developed out of the “African Cultural Heritage Sites and Landscapes Project” initiative under the leader ship of Prof H. Ruther in the Geomatics Division of the University of Cape Town. Since its beginning in 2005 the group comprising of three Scientific Officers (Ralph Schroeder, Roshan Bhurtha and Stephen Wessels) in addition to the project leader, has scanned and recorded some 60 sites in 13 African and two Middle East countries with a total of about 190 structures, monuments and rock shelters. A complete list documented sites, including mosques, churches, ruined palaces, temples and cultural landscapes, can be found here. However this count is somewhat futile and misleading as it counts a small rock shelter captured with ten scans as equal to a site such as the entire Petra area where 2500 scans were acquired.
Among the larger models generated over the past years are the rock churches of Lalibela, the Swahili sites of Kilwa and Songo Mnara, the entire Valley of the Queens in Luxor, the Fortress of Mozambique Island (7 billion points) , the pyramids of Meroe and Petra in Jordan (which to date tops the list with 25 Billion points). Zamani has also presented courses in documentation methods in a number of African countries.
At present the group has focussed on two sub projects, a database on the Slave Trade and one on the Swahili coast.
The not-for-profit project was initiated in 2005 with grants from the Andrew W. Mellon Foundation and continued through projects for or with UNESCO, the World Monuments Fund and the Getty Conservation Institute as well as numerous individual projects for international university departments of archaeology and history. Important contributions from individual philanthropists and laser scanner manufacturers and resellers such as Z+F and Leica kept the project alive. The Zamani group makes all efforts to digitise Africa’s important heritage before it is lost forever, however this initiative can only be sustained with donations and funded projects. The Zamani data are available for research and education.
And interactive 3D models can be found on https://sketchfab.com/zamaniproject