2020 Niobrara River Topobathymetric Lidar Validation – USGS Field Survey Data

Publication Date

2022-03-09

Start Date

2020-08-17

End Date

2020-08-28

Irwin, J.R., Danielson, J.J., Kim, M., Robbins, T.J., and Park, S., 2022, 2020 Niobrara River Topobathymetric Lidar Validation – USGS Field Survey Data: U.S. Geological Survey data release, https://doi.org/10.5066/P9PJ0Q8D.

Airborne topobathymetric lidar can provide high-quality topographic and bathymetric information over large areas. Lidar is an active remote sensing technology that employs laser ranging in the near-infrared (1064 nm) and the green spectral (532 nm) wavelengths to provide three-dimensional (3D) point information for objects, including the Earth’s ground surface, submerged topography, vegetation, and infrastructure. USGS 3DEP seeks to acquire and evaluate topobathymetric lidar over select pilot areas within the conterminous U.S. Detailed knowledge of integrated river system topography and bathymetry is essential for key science applications, such as inundation mapping, habitat characterization, and fluvial geomorphology. A sequence of field accuracy assessment surveys, using conventional surveying methods combined with ground based lidar (GBL), were conducted at test sites along the Niobrara River in Nebraska to evaluate the 3D absolute and relative accuracy of the airborne topobathymetric lidar data. Airborne lidar data accuracy is most commonly expressed in terms of the vertical error (RMSEz) of the Digital Elevation Model (DEM) generated from the lidar points that are classified as ground or submerged topography, with little or no regard to the horizontal accuracy of the point cloud. High accuracy 3D point data are necessary to estimate the 3D accuracy of airborne lidar data. This requires validation data that are three times more accurate than the airborne lidar data, such as point data collected from survey grade GNSS, total station, and GBL instruments. The survey data will be used to spatially assess the horizontal and vertical accuracy of the Niobrara River airborne topobathymetric lidar data that were coincidentally collected for 3DEP along with validating the vertical accuracy of the integrated National Topography Model (NTM) prototype DEM. This research will help 3DEP work toward operationalizing topobathymetric lidar by providing recommendations regarding topobathy lidar sensor performance and suitable site conditions for potential river acquisition surveys.

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