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GCN : September 2014
USGS ENHANCED ELEVATION MAPPING When the U.S. Geological Sur- vey was established in 1879, its main concern was to create accurate maps showing the locations of mountains, rivers and mineral resources to support westward expansion. What those early maps didn't offer, how- ever, was accurate elevation data, and ele- vation data is increasingly important to the economy, as well as to disaster response and other critical public and scientific gov- ernment services. According to a recent study commissioned by USGS, en- hanced elevation data could generate as much as $13 billion in benefits each year. The great- est benefits would be in flood risk management, infrastruc- ture and construction manage- ment, natural resources conser- vation and agriculture. The technology for enhanced elevation mapping is already available. Light detection and ranging --- or Lidar --- devices on aircraft can cover 50 square kilometers an hour, delivering 300,000 points of elevation data per sec- ond, accurate to between 4 and 8 inches of elevation. That's enough precision to not only support obvious efforts such as flood risk management, but it could even be used by vehicle navigation systems to minimize fuel consumption. There's one snag in the effort to map the country with Lidar, however: money. According to Kevin Gallagher, associate director of the Core Sciences Systems di- vision at USGS, it would cost $800-$900 million to collect Lidar data for the entire United States. "The bottom line is we don't have that kind of money in our budget," Gallagher said. So when the USGS launched its 3D El- evation Program (3DEP) in 2012 with the goal of generating a high-resolution eleva- tion map of the United States over the next eight years, it was clear that some creative partnering was called for. The first step in partnering was obvious. USGS created a 3DEP executive forum to loop in other agencies that have a vested interest in Lidar. Among the 13 agencies and department included are the National Oceanic and Atmospheric Administration, the Army Corps of Engineers, the Federal Emergency Management Agency, the En- vironmental Protection Agency and NASA. In addition to sharing data that results from 3DEP mapping, the agencies also share the costs of specific data collection efforts. "Our funding set-aside purely for elevation is relatively small," Gallagher said. "Last year our number was around $2 million. But we are able through part- nership funding to bring a larger sum of money to the table." STATES AND 3DEP USGS is also turning to the states as part- ners, with Alaska and North Carolina lead- ing the way. Nicholas Mastrodicasa, project manager at Alaska's Department of Natural Resourc- es, shares two concerns with USGS. First, he said, the state realized ear- ly on that it could not do the map- ping by itself and needs partners. Second, the state acknowledged the importance of gathering en- hanced elevation data for a variety of purposes, including emergency service, land management, vegeta- tion analysis, aviation safety and climate research. "We see a lot of things chang- ing the Arctic," Mastrodicasa said. "Coastal erosion is causing tribal villages to have to move, and that's an expensive proposition. Before you move a village you want to make sure you're moving it to where water resources exist and where flooding isn't going to occur." In collaboration with USGS, Alaska has now mapped approximately 50 percent of the state. Unlike with other states, how- ever, elevation mapping in Alaska is being conducted using IFSAR -- interferometric synthetic aperture radar. That's because Alaska has cloud cover much of the time and Lidar cannot penetrate cloud cover. A set of technical maps containing elevation data of the entire United States would generate public safety costs savings and more, backers say USGS chips away at high-res 3D map of US BY PATRICK MARSHALL 24 GCN SEPTEMBER 2014 • GCN.COM Dune migration at Jockey's Ridge State Park, N.C.