Archaeologists work with the material remains of the past, and their main goals are to document the patterned relationship among material remains and to reconstruct lifeways of cultures in the past. Conservation of remains is also an important object

for archaeologists. Copan is one of the major Maya cultures located in the Central America and flourished between A.D.300 and 900, known as the Classic period. Like other sites, the ruins are fragile; thus, they are easy to get damaged by weathering.

In addition, Copan site is opened for tourists, so there are always some possibilities of destruction. To seek the solutions for this problem, I decided to search on the Internet and look in archaeological magazines to find out how GIS is used to manage these problems.

As methods, I searched on the Internet and spent hours looking for data about the Copan site. I visited many web sites of archaeology and GIS. I also used EBSCO to look for articles on GIS projects at Copan.

Some web sites dealing with Copan contain academic report, and others are for tourism, but none of them were geo-referenced data. Worse, I could not find any article featuring the use of a GIS in Copan projects.

I found it very difficult to acquire archaeological data. A GPS and GIS are now broadly used in archaeological projects, but geo-referenced data does not seem to be available in public.

Since I came up with no data, my instructor suggested me to review and evaluate other archaeologists’ methods of acquiring data, so I would like to present one archaeological project in which GPS is employed.

In the GPS World April 1999 issue, the project dealing with Chavin de Huantar site in the northern Andes is portrayed by William Clay Poe, who is a GPS operator and professor of archaeology at Sonoma State University. This site is an UNESCO World Cultural Heritage, and the project is conducted by the Stanford Department of Anthropological Science. The aim of this project is to interpret the site’s architectural history through a combination of precise mapping and very selective excavation. GPS was applied to define the relationship of the existing local site grid to the Universal Transverse Mercator grid, and to true north, and gather additional positions. The GPS survey points were mostly collected in the open areas, and the theodolite was used to record points of the architectural monuments where the GPS rover loses satellite lock because of structure’s wall.

Poe set the base station which was a 12-channel, L1, C/A-code carrier tracking GPS receiver equipped with a dome antenna and used a roving receiver which is a 12-channel, L1, C/A-code and carrier-phase unit with a handheld datalogger. During the process, they set both the base station and the rover to record at five-second intervals. To confirm the consistency of the positional data on a daily basis, they set the rover on the same initial position, only about 3 meters from the base station antenna mast and logged the feature for 10 to 20 minutes when each file recorded. By gathering data for at least five minutes, recording a minimum of 60 positions at five-second intervals and keeping good satellite visibility, they achieved horizontal accuracy from 1.4 to 2.5 cm with 95 percent confidence levels. At the same confidence level, the vertical accuracy was 7-10 cm.

The methods used in this project seem to me well planned. They carefully figured out when is the best time for satellite reception and achieved great accuracy.

Recording locational data at archaeological sites would help to preserving archaeological remains and their context. It is necessary to employ a GPS as well as a theodolite to record locations in open areas and closed areas.

William Clay Poe, 1999. Archaeology in the Andes. GPS World, April: 23-28.