ARCE Sphinx Project 1979-1983 Archive

Overview

The ARCE SPHINX PROJECT (1979-1983) aimed to produce scale drawings (plans and elevations) of the Great Sphinx of Giza, where no scale drawings of this unique monument had been produced before, to map the greater Sphinx site, including three ancient Egyptian temples situated east of the statue, and the larger quarry forming the Sphinx "amphitheater." Objectives included elevations, profiles, and a detailed master plan of the Sphinx, detailed section and profile drawings showing the masonry restorations added to the statue, topographical maps of the Sphinx ditch and larger quarry, and maps of the structural geology of the site, showing stratification and faults.

The idea was that we could achieve a better understanding of the origin of the Sphinx and how the 4th Dynasty Egyptians created the Sphinx from careful, recorded observations of its structure and geology, and that a good part of the history of the Sphinx could be read from detailed survey and mapping of the stratified masonry on the Sphinx, and from the condition of the bedrock core under the earliest masonry, as well as from analysis of tool marks and mortar bonding the different phases.

Dr. James Allen, then Assistant Director of the American Research Center (now Charles Edwin Wilbour Professor of Egyptology at Brown University) applied as Project Director to the Egyptian Antiquities Organization to survey and map the Sphinx. Mark Lehner served as Field Director. Ulrich Kapp (German Archaeological Institute in Cairo) carried out the photogrammetric survey and plotted the master profiles and elevations of the Sphinx. Team members included Christiane Zivie-Coche (Director, Centre Wladimir Golenischeff, École Pratique des Hautes Études, Egyptology), Attila Vass (survey), Susan Allen (now, Museum of Fine Arts, Boston, survey), Peter Lacovara (then Museum of Fine Arts, Boston, now The Ancient Egyptian Egyptian Heritage and Archaeology Fund, survey) and Cynthia Schartzer (archaeology, survey), K. Lal Gauri (University of Louisville, geology), and Thomas Aigner (University of Tübingen, geology).

The ARCE SPHINX PROJECT ARCHIVE includes written, drawn, and color slide photographs and black and white photographs. Drawings include:

• Master elevations of the front and sides of the Sphinx, scale 1:50.
• Master plan of the Sphinx, scale 1:50
• Detailed maps of the 4th Dynasty Khafre Valley Temple, the Sphinx Temple, and the 18th Dynasty Amenhotep II Temple, scale 1:100
• Topographical and geological maps of the wider Sphinx “amphitheater,” scale 1:200
• 1:1,000 map of the Sphinx and modern installations to the East as of 1979
• Detailed architectural sections and elevations of the stratified ancient masonry layers applied to the Sphinx bedrock core body, scale 1:20 and 1:10
• 5,000 slides
• 2,716 black and white photographs
• Profile of the Sphinx area with water table measurements taken during 1981-82.

Methdological Notes

Lehner established a local survey grid Sphinx grid and defined coordinate values during the 1978 SRI project in 1978,and used this grid and these coordinate values during the ARCE Sphinx Project (1979-1983). The numerical values on the graphic records of the Sphinx, including the master plans and elevations, are based upon this coordinate system. Lehner chose an arbitrary point 3.5 m in front of the Sphinx's south forepaw on a line that approximates the east-west center axis of the Sphinx Temple. He defined this point as the intersection of east-west line N3000 and north-south line E500. Using an old transit with a built-in surveyor's compass and Vernier scale, the grid was oriented to magnetic North on February 20, 1978. We assigned grid coordinate values that decrease to the north and east and increase to the south and west in order to accommodate an expansion of the grid into the archaeological zone.

During the 1978 excavations of Zahi Hawass to the northeast across the modern road, a cement marker to the east of the Sphinx, near Nazlet es-Semman, was chosen as an arbitrary datum for elevations. This was defined as +10 m. This vertical control was transferred by differential leveling to grid points marked with small masonry nails in the floor around the Sphinx. Later, surveyor Attila Vass transferred down to the Sphinx Cole's (1925) values with respect to sea level from the survey pins at the corners of the Khufu Pyramid. The vertical values in all the ARCE Sphinx Project drawings are according to the local Sphinx arbitrary datum. However, the addition of 9.331 to any of the Sphinx values gives the height above mean sea level in meters according to our tie-in with the survey pins at the corners of the Great Pyramid.

In September 1979 the German Archaeological Institute in Cairo donated the use of their photogrammetric system and the services of surveyor, Ulrich Kapp, to the ARCE Sphinx Project. The survey grid was adjusted and checked with several theodolites. The orientation remained magnetic North as read on February 20, 1978. Kapp used the Jena-Optic stereo-metric camera SMK 120 with a base of 120 cm, and the Topcard B plotting system, to produce front, north and south elevations of the Sphinx, and master profiles through the statue every 5 m. The original drawings were plotted at scale 1:50.

To compliment the photogrammetric elevations of the Sphinx, Lehner produced a 1:50 master plan from a series of separate drawings that were locked together on the basis of 90-degree offset measurements from datum tape measures stretched between grid points. The base outline the top of the forepaws and top of the back were separate drawings produced by hand planning with offsets from grid lines that were projected up to these surfaces. This was facilitated by the ARCE Kern 1 - second theodolite and electronic distance measurer.

Lehner mapped the surface of the ledge formed by the masonry additions to the natural-rock lion body from planning points. Since the ledge follows the curves of the body at various heights, level lines segments were selected to advantage, so that a datum tape could be stretched between planning points, or end points, marked by small masonry nails. He mapped segments of the masonry ledge as separate drawings. Lehner located the end points of these datum lines by triangulation from grid points on the Sphinx floor. This allowed the separate drawings to be locked together under clear mylar on the drafting table.

To map the head, Lehner triangulated 63 points from grid points on the floor. The resulting plot was checked against "cuts" through the head and face from the photogrammetric elevations. A similar procedure was used to plot over-hanging bedrock ledges down the sides of the Sphinx body.

Lehner drew a series of detailed plans and profiles were drawn at scale 1:20 of various parts of the masonry around the sphinx. These profiles give information about the condition of the bedrock core of the Sphinx before the most ancient restorations NS illustrate the stratification of the various repairs to the Sphinx. A particularly detailed study was done of the masonry in the chapel of the Sphinx, located at the base of the chest between the forepaws. Each structural element was given a number and profiles were drawn to illustrate the structural relations between major parts of the masonry.

During the Project, Lehner worked with geologists K. Lal Gauri from the Stone Conservation Laboratory at the University of Louisville and Thomas Aigner from the University of Tübingen to produce geological maps, geological survey data, and geological profiles with ID tags for the geological strata comprising the Sphinx.

The Sphinx Computer Modeling Project (SCMP) was begun in January 1990 in connection with the preparation of the proposal of the Getty Conservation Institute to the Egyptian Antiquities Organization for conservation studies of the Sphinx. Jon Jerde, President of the Jerde Partnership Inc., an architectural firm in Venice, California, donated equipment, time and expertise, to produce the project. Tom Jaggers, CAD Director of the Jerde Partnership, carried out the computer work.

Jaggers used an ALR (Advanced Research Logic) Personal Computer and the Auto Cad (Release 10) program to digitize the 1:50 front and side elevations, the top plan, and the 1:200 map of the surrounding ditch. Jaggers connected the contours by adding a wirework frame in order to establish a plane, a process then called meshing. This allowed the computer to hide lines that should not be seen from a given point of view. After meshing, the Sphinx model was comprised of 250,000 faces, a face being one surface unit (the equivalent for a surface to a pixel for a line). Pure processing time was required in order to hide lines for a given point of view. See Jaggers (1991) for a more technical description of the Sphinx computer modeling.

Lehner used the Sphinx model to reconstruct the Sphinx's original appearance (for example with beard and nose intact), and its appearance after its actual reconstruction in the New Kingdom when it was entirely clad in the Phase I restoration masonry. The images of the reconstructed Sphinx were contoured and digitized in for 3D modeling by computer.

Potential Applications of the Data

History, Art history, Egyptology, Anthropology, Archaeology

Support

ARCE SPHINX PROJECT ARCHIVE Digital Data Base Project Support:

Antiquities Endowment Fund (USAID), The American Research Center in Egypt

Original ARCE Sphinx Project Support:

Edgar Cayce Foundation, Franzheim Synergy Trust, Chase National Bank of Egypt

Related Publications

Most of the ARCE Sphinx Project Archive remains unpublished. After the first year of the project, Lehner, in collaboration with Allen and K. Lal Gauri, published a preliminary report summarizing the work and understandings to that date (Lehner, Gauri and Allen 1980).

In his PhD dissertation, Lehner (1991) included a selection of drawings of the Sphinx structural history, as well as a selection of maps and photographs. This dissertation remains unpublished. We include it here as a narrative arc and guide that connects the various documents.

In 1992, as part of a symposium to study the Sphinx and its conservation, Lehner published summary of the ARCE Project Results with a selection of graphic records (Lehner 1992a). Also in 1992, Lehner published his reconstruction of the Sphinx as the 18th Dynasty restored the monument, 1,200 years after the 4th Dynasty, based on analysis of the Sphinx Project results (Lehner 1992b). Drawings and notes from this analysis and reconstruction form part of the Archive. In 1994 Lehner and Hawass published a popular article for Archaeology magazine, based on Sphinx Project results (Hawass and Lehner 1994).

Most of the Archive remains unpublished. The master plans and elevations of the Sphinx have never been published to a scale at which viewers can see the level of detail and data. Digital high-rez versions, accessed online, allows viewers to review and zoom in on any part or detail.

The following references include those cited above, and other publications that stem from the ARCE Sphinx Project 1979-1983 or that were important to the project.