GeoSCAPE

A 3D Visualization of On-Site Archaeological Excavation Using a Vectorizing Tape Measure

Written by: Jay Lee, Blair Dunn, Sandia Ren, Victor Su, and Hiroshi Ishii

GeoSCAPE is an application that facilitates capturing a 3D visualization of an archeological excavation using HandSCAPE, an orientation-aware digital tape measure (Figure 1). HandSCAPE is an input device for digitizing field measurements to visualize the magnitude and direction of the resulting vectors with computer graphics. Using embedded orientation-sensing hardware, HandSCAPE captures relevant vector information on each linear measurement and transmits this data wirelessly to a remote computer in real time. The GeoSCAPE software analyzes this data, using trigonometry to define vector equations in Cartesian coordinates. Using certain heuristics, these vectors are applied by GeoSCAPE to recreate an archeological excavation rendered in computer graphics.

The Application

An archeological excavation is examined and documented primarily using handwritten measurements, notes, and photography, which are often irreplaceable during the on-site excavation. To fulfill the need for efficiency and functionality in archaeological excavations, GeoSCAPE visualizes the primitive 3D objects created by measuring. It occurred to us that a new application of HandSCAPE could integrate on-site and laboratory archaeological research. By using HandSCAPE to perform measurement tasks with efficiency and speed, the user automatically defines the layout of the excavation on the laptop (Figure 2). As 3D spacing is an important factor in analyzing archeological work, GeoSCAPE provides an important step toward linking the physical archeological excavation with a virtual rendering on-site.

3D Visualization

Our current implementation of GeoSCAPE defines the relationship between the physical space and the virtual space as follows. The “anchor point” in physical space is one corner of the excavation and is represented in the application as a white sphere. This is also the origin of the 3D coordinate system in the virtual space. From this anchor point, a new reference frame is defined by making a vector in physical space and sending the data to the computer by pressing a button on the HandSCAPE device. Within this reference frame, three additional measurements are taken. These are used to define a cubic figure in the virtual space that represents the location of an artifact in the physical excavation. Issues of denoting perspective were also important. Measurement grids were added, as was a 3D compass. The compass, seen in the upper right corner of the screen shot, has its 3D rotation tied to the user’s movement of the virtual excavation. Other functionality introduced here includes a map of the excavated region, display of coordinates and dimensions for the artifact bounding boxes, the ability to create a multi-tier excavation site, and full 3D navigation.

Future Extensions

To provide a single source of access to information regarding the excavation, we are currently working on connecting GeoSCAPE to an archaeological database with notes, photographs, and other relevant information. This database is used during the excavation to aid in reconstruction of the site by referencing stored information. This would allow for immediate access of information pertinent to the objects being viewed and allow the user to better visualize the site. Another idea being pursued is integration of a GPS positioning device into the HandSCAPE tool. GeoSCAPE could link this to a map program to change the map view automatically depending on location and store the data in the database.

Acknowledgement

We would like to thank Louise Krasniewicz, Richard M. Leventhal, and Ken Stuart of the Cotsen Institute of Archaeology at UCLA for the discussion on the archaeological application. We also thank the members of the Tangible Media Group and our colleagues of the Things That Think consortium at the MITMedia Lab for their support of this research.

References

Dillon, B.D. (Eds). (1993). Practical archaeology: Field and laboratory techniques and archaeological logistics. Los Angeles: University of California Press, 33-38.

Lee, J., Su, V., Ren, S., & Ishii, H. (2000). HandSCAPE: A vectorizing tape measure for on-site measuring applications. In Proc. of Conference on Human Factors in Computing Systems CHI'00, 137-144.


Figure 1: The HandSCAPE tool (12 x 12 x 4.5 cm).



Figure 2: New Approach: GeoSCAPE is an on-site archaeological application of HandSCAPE, a digital tape measure with custom sensing electronics. It communicates through a RF signal and performs graphics rendering.