Preserving the Past for Future Generations

Modern 3D Technology Creates an Enduring Record of Fragile Historic Monuments

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In 2002, Ben Kacyra founded California-based nonprofit CyArk ( to apply accurate, portable laser-scanning technology to preserve the world’s cultural heritage sites. This data is analyzed and made available for visualization in ArcGIS.

Kacyra originally developed the scanning technology for documenting nuclear power plants, oil refineries, and other industrial and civil engineering structures. CyArk’s methods are fast and accurate. Pulsed lasers generate 3D point clouds, which render surfaces at an accuracy within millimeters. Combined with high-resolution photography and traditional surveying techniques, the data points make it possible to create highly detailed media–architectural drawings, photo-textured animations, 3D fly-throughs–that digitally preserve knowledge about heritage sites and help protect the information against natural disaster, war, and neglect while also making the sites accessible to the world. Among the sites already digitally preserved are the Mayan temples in Mexico, the leaning tower of Pisa, and Mount Rushmore.

"Our goal is to preserve these sites and spread information about them throughout the world," said Tom Greaves, executive director of CyArk. "Using GIS and 3D imaging technology, we are able to aid in archaeology and conservation by extending an image to include animation and visualization and investigate these sites and structures in new ways."

GIS for Heritage Preservation
Laser scanning is only the start of the process. CyArk has taken advantage of Esri’s Nonprofit Program and uses ArcGIS to incorporate supplementary datasets such as historic maps, photos, and up-to-date geographic data. For many projects, analysis is required for research and modeling, and this is also done in ArcGIS.

As an example, ArcGIS and terrestrial LiDAR were used for mapping historic structures and landscapes at ancient Merv, which is in the deserts of the central Asian nation of Turkmenistan and has been designated a World Heritage Site by the United Nations Educational, Scientific and Cultural Organization (UNESCO). UNESCO promotes international cooperation among its 193 member states and 6 associate members in the fields of education, science, culture, and communication. The ability to use topographic and hydrologic analysis tools in combination with detailed LiDAR data created new information to better aid conservation.

At Merv, CyArk worked with its partner, the University College London’s Institute of Archaeology, to document multiple earthen architecture (adobe) structures and the immediately surrounding landscape. In the 1950s, a large earthen canal was carved through the desert to feed the cotton fields of the former Union of Soviet Socialist Republics (USSR). The vast dirt canal allowed huge volumes of water to seep into the surrounding landscape and has drastically raised the water table of the area. As a result, each year’s rains are no longer quickly absorbed by the soil, causing pooling and water basins near the wall foundations of adobe structures that have stood anywhere from 700 to 2,300 years. These ancient monuments have therefore begun suffering catastrophic collapse in the last few decades as the bases of walls have eroded. The laser scan data was used to record the structures in their current state as well as the surrounding landscape. A detailed contour map of the terrain was then created at approximately 10-centimeter intervals. The contour data was brought into ArcGIS, and a digital elevation model (DEM) was created. From the DEM, powerful hydrologic analysis tools in ArcGIS were used to map water flow and identify problems around some of the threatened structures. With this information about the natural drainage paths and basins causing dangerous pooling, site archaeologists can improve water drainage away from the structures, helping mitigate erosion and collapse.

Defining a UNESCO Site
CyArk along with other organizations, have been hard at work preserving the California Mission Trail–El Camino Real – with digital technology. This 600 mile historic route stretches from San Diego to north of Sonoma, and maps out the Spanish colonization of California. The route contains many historic buildings including missions, presidios and pueblos. This is an important project as it is helping lay the groundwork and initial research required for nominating the route as a UNESCO World Heritage Route. While parts of the historic route have been preserved in their original state, there are many segments that have been upgraded and are now part of the California modern-day highway system, including US Route 101 and State Route 82. There have been many changes since the route began in 1769. Understanding the original contextual landscape that lies underneath today’s urban landscape will take a lot of effort and funding. CyArk has received almost 10 percent of the seed funding for this vast undertaking, which will digitally preserve the route and its 21 missions, 4 presidios, 3 pueblos, and numerous other buildings.

The first mission the CyArk team tackled is close to them–Mission Dolores of San Francisco. Dolores was founded June 29, 1776, and is reported to be the oldest intact building in San Francisco, as well as the oldest original intact mission along the route. The mission also lies adjacent to the San Andreas Fault, making it a fragile, yet invaluable, resource. The mission cemetery contains the remains of many significant members of San Francisco and California history including thousands of Native Americans.

Scanning the Past
In mid-July, CyArk’s Scott Lee and Alexander Rienhold began the digital preservation process to document Mission Dolores. Fieldwork was conducted using two terrestrial scanners, the Leica C10 and the smaller Faro Focus3D. The first day began with scanning the exterior of the building and the cemetery. At the end of the first day, CyArk had captured over 75 scans with the two scanners, including panoramic images to provide color information to create photo-realistic 3D data.

The mission interior was scanned on the second day, including the loft and attic. Jaime Pursuit, development manager with CyArk, joined Lee and Rienhold in the field to meet with some prominent visitors, lead a tour, and introduce the technology being employed. One of the documentation team’s most interesting discoveries was the original wood beams in the attic (from 1776), which were tied together with leather straps that still had animal hair on them.

"As a trained archaeologist, this was a delightful surprise and evidence of this mission’s authenticity," said Rienhold.

At the end of the day, the Faro scanner was lowered from the attic into a two-foot gap between the current altar and the original adobe wall. The original adobe is covered in Native American murals, protected by the detached modern wall. The gap was narrow, limiting access, but the team managed to capture parts of these original works. Although three days of fieldwork were planned, the two scanners worked flawlessly and with speed and precision, and the team completed the work by the end of the second day.

Mapping the Mission Route
CyArk staff went back to an original map from 1823, which was provided by the Santa Barbara Trust for Historic Preservation, and used that to locate the route and the sites themselves. The map was registered to modern-day maps using ArcGIS. "Combining this very old information from 1823 meant that they didn’t quite match up great with the newer maps, but our intention is to create some visualizations for the public to understand how El Camino Real looked in the past," said Greaves.

These views of the road will also be combined with photo-realistic 3D models derived from the laser scan data and digital photos. "Combining these technologies and being able to navigate from one site to the other is something that we could barely do even two years ago," said Greaves. "Now we are able to create materials from this data that will be compelling for students, researchers, and the general public. Now you can visit more sites virtually than you could ever hope to otherwise."

Other applications only made possible by the combination of engineering-grade information and geo-referenced data include seismic refits, which are especially helpful for the missions. El Camino Real follows the San Andreas Fault, which created a natural valley in California. "It’s not a question of if–it’s when–an earthquake happens," said Greaves. "We’ll be able to understand how these structures were built. There are many possibilities for engineers and architects to take advantage of this rich dataset."

Karen Richardson is a writer at Esri, based in Redlands, California.

A 766Kb PDF of this article as it appeared in the magazine complete with images is available by clicking HERE