USGS National Elevation Dataset (NED) moving to Lidar-based elevation model
The USGS National Elevation Dataset (NED) is transitioning to a Lidar-based elevation model. This transition is part of the 3D Elevation Program (3DEP) initiative, whose goal is to systematically collect enhanced elevation data in the form of Lidar data over the conterminous United States, Hawaii, and the U.S. territories, with data acquired over an 8-year period. Interferometric synthetic aperture radar (IFSAR) data will be collected over Alaska, where cloud cover and remote locations preclude the use of Lidar over much of the state (yes, physical geography still matters!).
This initiative was born in response to a study funded by the USGS named “The National Enhanced Elevation Assessment.” The study documented business uses for elevation needs across 34 federal agencies, agencies from all 50 States, selected local government and Tribal offices, and private and not-for profit organizations. Each need was characterized by the following:
- Data accuracy.
- A refresh cycle for the data.
- Coverage for geographic areas of interest.
Conservative annual benefits for flood risk management alone are $295 million; for infrastructure and construction management, $206 million; and for natural resources conservation, $159 million. Results are detailed in the Dewberry report on the National Enhanced Elevation Assessment, which details costs and benefits, how the data will be collected, standards and specifications, and organizations involved in the effort. An additional report details how the data could help in terms of taking action for climate change.
How will this affect us in the geospatial data community? The NED activities and website will continue until a full transition to 3DEP is completed. 3DEP planning and research is underway at the USGS to transition to a unified service that will provide both gridded bare earth data products and point cloud data, along with capabilities to produce other derived elevation surfaces and products from 3D data. When the data does appear, data users should notice the difference in resolution and quality. In our book, we detailed the rise of Lidar data, and since its publication, these data sets have greatly expanded in quality and availability.