Science / Medicine : Jungle Computer Probes Mayan Ruins : Archeology: Design software and laser mapping can chart a site more accurately and quickly than traditional methods.

The Mayan culture remains an enigma. The remnants of roughly a thousand communities have been identified, but in most cases not much is known about them. Credit that to their locations--often in the heart of some of the world’s most forbidding jungles--and to the fact that Mayan history has not been as well documented as that of the ancient Mediterranean civilizations.

What is left of this vast legacy is disappearing rapidly. Even those remains that survive the elements may not survive the looters or the needs of modern civilization. Today, Mayan statues might wind up in somebody’s villa, while building stones are recycled in modern schools or highway roadbeds.

Modern archeology has barely kept pace with the rate of deterioration. Even if funding were infinite, there are not enough Mayan scholars to go around, says archeologist and Mayan specialist Nicholas Hellmuth of Rollins College in Florida.

And even when a ruin gets the right attention, the process of mapping it often falls short. But that is changing now that Hellmuth has introduced the personal computer into the heart of the jungle.

Using computer-aided design (CAD) and highly precise laser mapping techniques to chart the ruin site, the researcher has produced animated displays of the ruins as they are--and once were, at the height of their splendor 17 centuries ago.

Traditional methods involve a lot of elbow grease and subjectivity. First, a compass was used to determine a structure’s orientation; measuring ropes or tapes established its dimensions, and an artist’s sketch provided the visual rendering. Later, surveying techniques commonly associated with building or highway construction added a degree of geometric accuracy, but they still fell short. “These methods make a lot of assumptions, such as that the lines are always straight and that everything is always squared off,” said St. Louis architect Daniel Hellmuth, Nicholas Hellmuth’s brother.

Photogrammetry, a process using stereoscopic cameras, enabled archeologists to visually reconstruct a site stone by stone (such a process is being used to help reconstruct the Great Sphinx).

But photogrammetry is costly and time-consuming, requiring that the pictures be assembled back at the lab to derive the building’s geometric coordinates. By the time a site is mapped, a hurricane could have washed most of the remains away.

To gain a critical edge in the race against time, Nicholas Hellmuth tried yet another tack: Backpack a personal computer into the heart of the jungle.

But computers can be delicate. Traditionally, large mainframe systems serving businesses were housed in cooled control rooms. When the PC came along, it became possible to operate units at room temperature--as long as there was a room in which to situate one.

There were plenty of rooms at the Mayan site--a 44-room palace at Santa Rosa Xtampak, an ancient regional capital in the heart of the Yucatan. But the temperature inside was hardly what is thought of as room temperature.

“We had climate control from Mother Nature,” said Hellmuth, noting that temperature and humidity percentage both typically ranged in the high 90s during the course of the project, which, as luck had it, was done during the height of the rainy season. “People swore the computer wouldn’t work, that fungus would grow on the floppy disks, and that the power surges (from the portable generator) would blow the computer.”

But the computer lived to tell the story--one with a few unlikely plot twists. “None of the walls were perpendicular. Not one of them went up in a straight line for more than a few inches,” said team member Daniel Hellmuth, who plotted the data on some of the palace’s rooms, vaults and stairwells on the PC using AutoCAD, a popular CAD program. “The Mayans weren’t sloppy,” said Nicholas Hellmuth. “They were interested in monumental ideas, and the fact that the walls weren’t straight wasn’t very important to them.

“These people were incredible engineers,” he added, noting that many of the palaces they constructed dwarf anything built in southern Mexico or Guatemala since.

Ordinary surveying may not have caught all these irregularities, while photogrammetry--which was also used at Xtampak to validate the CAD data--would not have revealed them until several months later. Furthermore, it is difficult to take a stereoscopic photo inside a closed space and get it properly correlated.

Currently, a team from the Technical University of Graz, Austria, is analyzing the photogrammetric data of the palace exterior, while Hellmuth’s team is assembling CAD data to produce three-dimensional, shaded visualizations of the winding internal staircases. The ultimate goal of the project, says Hellmuth, is to train local archeologists to use inexpensive tools like CAD to document their heritage before it disappears.

The presence of a CAD system on site also provided more immediate advantages. CAD’s precision, said Daniel Hellmuth, quickly revealed gaps in the data. Furthermore, added Nicholas, the computer running the CAD program could also be used to write the field report while the work was still under way, making it more accurate and complete.

This is not the first time that CAD has been used in archeology, but typically it had been run back in the lab to tabulate field data. “I wouldn’t be surprised if CAD will be used in the field a lot more in the future,” said University of Chicago Egyptologist Mark Lehner. “But I don’t know of anyone taking it out there now.”

Besides filing more accurate and complete reports, perhaps the most significant advantage of using CAD may be in visualization. Animated displays can depict eerily accurate walk-through views of the ruins.

The animations are not just bells and whistles, insists Hellmuth. They could be used to let people walk through the ruins on a computer screen in a museum, rather than trampling all over the site. They could also become critical in the increasingly competitive quest to solicit financial support from foundations.

In fact, such visualizations may soon become necessary now that the United Nations Educational, Scientific and Cultural Organization is frowning on site restorations that, in the past, proved merely cosmetic. Under the new international guidelines, archeologists will be allowed only to shore up existing ruins, not rebuild them.

CAD may help in those consolidations, said Atlanta-based consulting engineer James O’Kon, adviser on the project. CAD data could be fed into structural analysis programs that can help project workers decide how to reinforce existing ruins.

With all its advantages, noted the University of Chicago’s Lehner, CAD still lacks the fine detail of photogrammetry. (Lehner is using photogrammetry as part of the Sphinx restoration project.) “If you want a detailed map on how the stones are placed, you will need photogrammetry,” he said. Such detail, responded Hellmuth, is overkill when mapping individual sites cluttered with vegetation, such as Xtampak, or ancient cities involving large numbers of buildings.

But in the future, it might not be an either-or question. Hellmuth predicts that CAD and photogrammetric technologies could merge within five years, thanks to more powerful personal computers. With such a system, technicians would take digitized stereoscopic pictures, rather than photographs, on the spot, readily feeding them to a computer.

The Xtampak expedition, conducted in mid-1989, was a joint undertaking of the Foundation for Latin American Anthropological Research, a publicly funded nonprofit organization founded by Hellmuth, and the Universidad Autonoma de Campeche in the southern Yucatan peninsula, where the ruins are located, under the leadership of Prof. William Folan of Campeche.