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Back in 2005, staff at the National Oceanic and Atmospheric Administration (NOAA) realized that it was difficult to locate LiDAR coastal datasets because of the lack of a comprehensive list of available data, so a group started searching among state, county and local government agencies for existing datasets. The result was the first operational inventory of elevation data along United States coastlines.
“At NOAA, we talked about the need for an inventory for several years before we implemented the idea. Hurricane Katrina really pushed us to start an inventory for the Gulf of Mexico,” says Dr. Kirk Waters, physical scientist at NOAA. “It was harder than it would seem to create the inventory because every dataset had to be searched out and evaluated before being included. Our focus was data available in the public domain that met our quality specifications.”
There has been a longstanding coordination effort relative to elevation data acquisition planning and specifications through the National Digital Elevation Program (NDEP). NDEP is comprised of federal agencies and selected state organizations concerned with promoting the exchange of digital elevation data among government, private and nonprofit sectors and the academic community, and establishing standards and guidance that will benefit all users. While individual NDEP agencies maintained information on their own data holdings, the importance of having a complete inventory of available elevation data became clear in 2010 when the Federal Emergency Management Agency (FEMA) was required to present a National Digital Elevation Acquisition and Utilization plan for floodplain mapping to Congress. Shortly after, the need for an inventory to support the evaluation of the business case for a national elevation program became apparent. FEMA, USGS and NOAA, all part of NDEP, coordinated their efforts to identify gaps in existing elevation data, while USGS led the business case evaluation. Thus, the U.S. Interagency Elevation Inventory (USIEI) and the 3D Elevation Program (3DEP) proposal to collect LiDAR and IFSAR data across the United States was born.
“The USIEI provides an index of available topographic and bathymetric data sets, a viewer to display the data, useful project level metadata and information about how and where to access the data,” says David Saghy, geographer at USGS. “The NDEP is the coordination body which facilitates interaction among federal agencies concerned with elevation data. The NDEP accomplishes this through monthly meetings to discuss project level coordination and partnership opportunities, as well as through the development of elevation product standards and specifications. The USIEI helps us avoid data duplication and promotes efficient project management.”
Although the original driving force for creating the elevation data inventory was floodplain mapping, the demand for more accurate elevation data is now coming from a variety of sources, in part fueled by widespread access to high-resolution imagery and the rapid acceptance of LiDAR for a growing number of applications. In response to this perceived demand, the 2011 National Enhanced Elevation Assessment (NEEA) was conducted to document elevation data requirements and to estimate the costs and benefits of meeting those requirements with LiDAR and IFSAR. Led by the USGS and consulting firm Dewberry, study participants came from 34 federal agencies, agencies from all 50 states, selected local government and tribal offices, and private and not-for-profit organizations. The study identified 602 mission-critical activities that could be addressed by enhanced elevation data and built a business case to justify the investment required to carry out the 3DEP proposal.
“Twenty-five different scenarios were analyzed, comparing data specifications and the cost-benefit of each,” says Allyson Jason, geographer at USGS. “The optimal product mix for LiDAR data of the conterminous U.S. at Level 2, which is 9.25 centimeters vertical accuracy, and IFSAR data of Alaska is estimated to cost $147 million per year for eight years compared to $690 million of benefits received per year, which is a very conservative calculation.”
“While the study focused primarily on the public sector benefits, our data download statistics from NOAA’s Digital Coast indicate that over half of LiDAR data users are in the private and academic sectors,” says Waters.
The NEEA study identified these business activities as receiving the highest potential annual benefits from comprehensive enhanced elevation data:
1. Flood Risk Management
2. Infrastructure and Construction Management
3. Natural Resources Conservation
4. Agriculture and Precision Farming
5. Water Supply and Quality
6. Wildfire Management, Planning and Response
7. Geologic Resource Assessment and Hazard Mitigation
8. Forest Resources Management
9. River and Stream Resource Management
10. Aviation Navigation and Safety
The USIEI is vital to the success of 3DEP to offer a baseline picture of the data available and to track continuous updates. In the current USIEI, 14 attributes are collected for topography and seven attributes are collected for bathymetry to give users a better idea of dataset quality. The topographic portion of the elevation inventory was last updated August 2013, and USGS and NOAA update the information annually. The bathymetric information is current as of November 2012.
3DEP will be fully implemented as a program beginning in January 2015, including management oversight, program planning mechanisms and the anticipated funding profile. The responsibility for program oversight will be shared jointly between USGS and NOAA, with USGS primarily concerned with inland areas and topographic data and NOAA focusing on coastal areas and collection of topographic and bathymetric data. This joint responsibility is mandated through the Office of Management and Budget Circular A-16, which addresses coordination of federal geospatial data collection activities. Data are already being collected that will be an integral part of 3DEP, with a full dataset projected to be complete by 2023.
“It is pretty well understood by all parties that there are substantial benefits across the board to a full implementation of 3DEP, but the fiscal climate is uncertain,” says Saghy. “To do this right, the agencies need a reliable funding stream to partner with other organizations and take advantage of multi-year data collection programs. We are encouraged by the fact that 3DEP has been recognized by the current administration with budget increases for NOAA and USGS in the proposed budget.”
“The next step is arriving at a unified acquisition strategy with member agencies,” adds Saghy. “We want to focus on areas where there are the most benefits. If a state or university has an acquisition plan, we will leverage their funding with some federal help, but first we need to set up internal criteria to evaluate acquisition projects against the goals of the overall program, which include consolidating elevation data in one location and developing the infrastructure needed to store nationwide point cloud data.”
“We really see the USIEI and 3DEP as great examples of effective interagency coordination,” Jason says. “By leveraging the technical capabilities and staffing footprint of multiple agencies, we’re accomplishing more and the result is useful to the greatest number of people possible.”