USGS chips away at high-res 3D map of the United States
- By Patrick Marshall
- Aug 29, 2014
When the U.S. Geological Survey 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, however, was accurate elevation data, and elevation data is increasingly important to the economy, as well as to disaster response and other critical public and scientific government services.
According to a recent study commissioned by USGS, enhanced elevation data could generate as much as $13 billion in benefits each year. The greatest benefits would be in flood risk management, infrastructure and construction management, natural resources conservation 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 second, 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 division 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 Elevation Program (3DEP) in 2012 with the goal of generating a high-resolution elevation 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 Environmental 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 partnership funding to bring a larger sum of money to the table. Federal agencies are all contributing different amounts of money driven by their needs.”
USGS is also turning to the states as partners, with Alaska and North Carolina leading the way.
Nicholas Mastrodicasa, project manager at Alaska’s Department of Natural Resources, shares two concerns with USGS. First, he said, the state realized early on that it could not do the mapping by itself and needs partners. Second, the state acknowledges the importance of gathering enhanced elevation data for a variety of purposes, including especially emergency service, land management, vegetation analysis, aviation safety and climate research.
“We see a lot of things changing 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.”
Mastrodicasa expects the need for such data only to grow more urgent. “Tundra is getting permeable, so the water resources that are there today may not be there tomorrow. We need to have a better understanding of hydrography, and we can’t really do that without good elevation data,” he said. “It’s important we get it right, and that we get it now.”
In collaboration with USGS, Alaska has now mapped approximately 50 percent of the state. Unlike with other states, however, 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. Still, while IFSAR can penetrate cloud cover, it’s not as accurate as Lidar.
North Carolina has also been an early partner in 3DEP. In fact, according to John Dorman, director of North Carolina’s Geospatial and Technology Management Office, the state started collecting its own Lidar data as early as 2000, primarily for flood hazard mapping, transportation roadway corridor preliminary design and streambed mapping.
“Around 2008 we started looking at the elevation data we had and told ourselves we would keep our eyes out for opportunities to update the data because the technology was improving so much we were able to collect a lot more accurate points for a lesser cost,” said Dorman, adding that 3DEP is that opportunity.
Thanks to sharing costs and coordinating with 3DEP, Dorman says that North Carolina has already collected enhanced elevation data for 40 counties, representing about half the state.
And cost sharing for gathering the elevation data isn’t the only benefit for states from the 3DEP program. “We recognized early on the benefit of having a data set that has a single specification and compliance standards that everybody could use,” Gallagher said. “USGS provides leadership in terms of standards setting, organization and contracting.”
So far, however, even with existing partnerships, the 3DEP effort is coming up short on funds. To reach the goal of mapping their entire country in eight years, Gallagher said, would require $150 million a year.
“Our goal was that of the federal agencies could put together about $100 million, and we would expect states to contribute another $50 million,” he said. “We are not at those numbers yet. Last year, as a nation, we spent about $50 million total on enhanced elevation data.”
As a result, by mid-2014, enhanced elevation data has been collected for only 4 percent of the country.
Having developed the standards for data collection and having refined the processes of partnering with other government entities, USGS is now looking to expand those partnerships.
Accordingly, this summer, the agency issued a broad agency announcement inviting additional federal agencies, state and local government, tribes, academic institutions and the private sector to submit proposals. “What we’re trying to do with the BAA is reach a broader audience,” Gallagher said.
Gallagher added that as the amount of enhanced elevation data grows, he anticipates a boom in applications. “Once the data is acquired, I expect a whole industry to evolve out of this,” he said. “Decision support tools, visualization tools, precision agriculture, vehicle navigation – it goes on and on and on.”