In spring 2011, engineers using a tripod-mounted laser shot 50,000 beams per second at Mission Dolores, San Francisco's oldest standing structure. Over the course of 2¿1/2 days, they repositioned the tripod more than 120 times, bathing every nook and cranny of the mission and its grounds with the emerald-green laser.
The goal: create 3-D digital blueprints of the historic landmark to make sure it remains part of California's landscape forever.
Up and down the coast of the Golden State, engineers from Oakland-based nonprofit CyArk are in a race against time, using laser-scanning technology to digitally preserve an important part of California's heritage: the 21 missions, four presidios and three pueblos of the California Mission Trail, commonly known as El Camino Real.
"The missions are critically important to the history of California and of the United States," said CyArk director Ben Kacyra, 72, a former civil engineer. "And they are in extreme danger -- and have been for many years -- because they all lie along the 'ring of fire.'"
More precisely, they are vulnerable to earthquakes because the Mission Trail overlaps a large portion of the San Andreas Fault. Indeed, each of the missions has been damaged to some degree by seismic activity. As a result, California in 1995 mandated that seismic retrofits of the missions be completed by 2015. Because of the enormous costs of the retrofits -- $10 million to $20 million per site -- work has been completed at only a handful.
But should the Big One reduce one or more of the historic buildings to a pile of rubble before it's retrofitted, architects could use the laser scans to build nearly identical structures, Kacyra said. Each mission is raising about $70,000 -- a mix of public and private funds -- to do the work.
Built between 1769 and 1823 by Spanish monks every 30 miles from San Diego to Sonoma as part of a large-scale effort to convert the indigenous population to Christianity, the missions were the region's centers of agriculture and trade for more than 100 years. "The missions basically were the foundation of California," said Julie Ferraro, museum director at Mission San Luis Rey in Oceanside.
Kacyra originally designed his laser-scanner as a portable tool to make highly accurate 3-D digital blueprints of dangerous sites, such as nuclear reactors, that are hard for surveyors to access. But CyArk has since used the $100,000 devices all over the world to digitally preserve dozens of well-known monuments, including Mount Rushmore, the ancient Roman city of Pompeii and the Leaning Tower of Pisa. Within the next few years, CyArk hopes to scan 500 heritage sites around the globe.
"It's not the heritage sites themselves, but what they represent and the stories they tell us that are so important," Kacyra said.
He has a passion for history and architecture, passed down to him from his engineer father, while growing up in the northern Iraqi city of Mosul. During long walks, his father told him stories of the Assyrian ruins that remain sprinkled throughout the ancient city, known as Nineveh during biblical times.
Immigrated in 1964
Kacyra immigrated to the United States in 1964. A few years later, after earning a master's degree in civil engineering from the University of Illinois, he moved to the Bay Area to begin a career in engineering. In 1992, he founded a company to develop the lunchbox-size laser scanner. He eventually sold the technology to a Swiss company -- and then looked around for what to do next.
He was inspired to found CyArk -- a mash-up of "cyber" and "archive" -- after the Taliban destroyed the Banyan Buddhist statues in Afghanistan in 2001 and an earthquake flattened the ancient Iranian mud city of Bann in 2003.
"It affected me very deeply," he said. "I felt the technology we have could digitally preserve these heritage sites for future generations."
Unlike cultural artifacts tucked away safely in museums, cultural heritage sites are constantly at risk. They are at the mercy of the sun, wind, rain, natural disasters and vandalism.
In 2009, CyArk completed one particularly timely scan in the hills of central Uganda. Thatched huts serving as the final resting places of the last four kings of the 700-year-old Buganda Kingdom burned to the ground in March 2010. Fortunately, CyArk had digitally preserved the royal tombs -- designated by the world's premier heritage authority, UNESCO, as a world heritage site. The scan includes all the information architects need to rebuild the tombs to the exact specifications of the originals.
Prince James of the Buganda Kingdom contacted CyArk the day after the fire about using the scans to rebuild. Political turmoil, however, has delayed the project.
CyArk's scanner is designed to sweep a structure's surface with tens of thousands of laser beam pulses per second to record details about every corner, ceiling beam and window placement. The laser beam strikes a precise portion of the object, then ricochets back to the scanner's detectors. The time it takes for the laser beam to travel back shows just how far away that part of the object is. Computers convert these laser measurement points -- about 1 billion were made of Mission Dolores -- into a digital blueprint accurate to within a millimeter.
The scanners also use special photographic techniques to assign each point with a color value and texture. Finally, the various scans are digitally stitched together to form a complete 3-D model.
It's a formidable advance over conventional survey methods, said Elizabeth Lee, CyArk's director of operations. "A good surveyor might collect 1,000 data points in a single day," she said. "These machines capture 50,000 points in a single second."
UC San Diego archaeologist Thomas Levy agreed. "Three-dimensional laser scanning of ancient monuments represents the best way to make a detailed digital record of an archaeological site," he said.
CyArk has scanned four California missions: Mission Dolores, Mission San Luis Rey, Mission San Carlos Borromeo de Carmelo in Carmel and Mission San Juan Bautista. Kacyra hopes to finish the remaining missions over the next three years.
CyArk plans to make the scans of the missions available on its website for people around the world to tour the landmarks virtually. Scans for Mission Dolores are already posted on the site: www.cyark.org.
"If your house catches fire, and after you get the kids and the pets out, what's the next thing you reach for?" Kacyra asked. "Everyone answers, 'My picture album.' The equivalent for the human race are these heritage sites."
Contact Chris Palmer at 408-920-5782. Follow him at Twitter.com/palmer_cr.
Most of the funds for doing laser scans of the missions have come from the California Missions Foundation, the Northern California Institute of Classical Architecture and Art, private donors and a Save America's Treasures grant from the National Park Service.
Contact Elizabeth Lee, CyArk's director of operations, at firstname.lastname@example.org or 510-832-5440 to inquire about contributing to the digital preservation effort.