2019-2020 NOAA NGS Topobathy Lidar DEM: Coastal VA, NC, SC

NOAA Florence Topobathymetric Lidar data were collected by NV5 Geospatial (NV5) in 9 blocks from 20191126 - 20200825 using the follow sensors:

Block01 -Riegl VQ880GII system

Block02 - Riegl VQ-880-G and Riegl VQ-880-GII systems

Block03 - Riegl VQ880G, Riegl VQ880GII, and Riegl VQ880GH systems

Block04 - Riegl VQ880GII and Leica Chiroptera 4x systems

Block05 - Riegl VQ880GII, Leica Chiroptera 4x and Hawkeye systems

Block06 - Riegl VQ880GII, Leica Chiroptera 4x and Hawkeye systems

Block07 - Riegl VQ880G, Riegl VQ880GII, and Leica Chiroptera 4x systems

Block08 - Riegl VQ880G and Riegl VQ880GII systems

Block09 - Riegl VQ880G and Riegl VQ880GII systems

This dataset includes topobathymetric data in a LAS format 1.4, point data record format 6, with classifications in accordance with project specifications and the American Society for Photogrammetry and Remote Sensing (ASPRS) classification standards.

This data set also includes LiDAR intensity values, number of returns, return number, time, and scan angle. The 100 meter buffered project area consists of approximately 3,075,010 acres along the Eastern coast of Virginia, North Carolina, and South Carolina.

The delivered classified lidar data were then transformed from ellipsoid to geoidal height (Geoid18) and used to create topobathymetric DEMs in GeoTIFF format with 1m pixel resolution.

This lidar data was required by National Oceanic and Atmospheric Administration (NOAA) and the National Geodetic Survey (NGS), Remote Sensing Division Coastal Mapping Program (CMP) to enable accurate and consistent measurement of the national shoreline. The CMP works to provide a regularly updated and consistent national shoreline to define America's marine territorial limits and manage coastal resources.

This dataset includes all lidar returns. An automated grounding classification algorithm was used to determine bare earth and submerged topography point classification. The automated grounding was followed with manual editing. Depth values were adjusted per sensor to NOAA provided ground truth data. Bathymetric intensity values were normalized for water depth. Classes 2 (ground), 40 (submerged topography), and 43 (submerged object) were used to create the final DEMs. The full workflow used for this project will be documented in the NOAA Florence Topobathymetric Lidar final report, to be provided upon project completion.

Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the Office for Coastal Management or its partners

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Block06

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Block09

Data is available online for bulk or custom downloads

None

Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations.

OS Independent

Lidar horizontal accuracy is a function of Global Navigation Satellite System (GNSS) derived positional error, flying altitude, and INS derived attitude error. The obtained RMSEr value is multiplied by a conversion factor of 1.7308 to yield the horizontal component of the National Standards for Spatial Data Accuracy (NSSDA) reporting standard where a theoretical point will fall within the obtained radius 95 percent of the time (ACCr).

Absolute accuracy was assessed using both Non-Vegetated Vertical Accuracy (NVA) and Vegetated Vertical Accuracy (VVA) survey methods. Survey checkpoints were evenly distributed as feasible throughout the project area. NVA compares known ground check point data that were withheld from the calibration and post-processing of the lidar point cloud to the derived gridded bare earth DEM. NVA is a measure of the accuracy of lidar point data in open areas with level slope (less than 20 degrees) where the lidar system has a high probability of measuring the ground surface and is evaluated at the 95% confidence interval (1.96*RMSE). Project specifications require NVA meet 0.196 m accuracy at the 95% confidence interval. Ground check points located in land cover categories other than bare earth, urban, or submerged topography were used to compute the Vegetated Vertical Accuracy (VVA). Project specifications require VVA meet 0.36 m based on the 95th percentile tested against the derived bare earth DEM.

Submerged topography points were tested separately to calculate accuracy and usually occurred in depths up to 1m. Project specifications require submerged topography shall meet a vertical RMSE of QL2b specified in the Draft National Coastal Mapping strategy 1.0 which is equivalent to 0.30 m RMSE at a depth of 1 m. Please refer to the NOAA Hurricane Florence Topobathymetric lidar final data report for final accuracies, to be provided upon project completion.

Block01: Based on a flying altitude of 400 meters, an IMU error of 0.002 decimal degrees, and a GNSS positional error of 0.015 meters, the RMSEr value for the Delivery 1 area is 0.029 meters, with a ACCr of 0.05 meters at the 95% confidence level.

Block02:Based on a flying altitude of 400 meters, an IMU error of 0.005 decimal degrees, and a GNSS positional error of 0.015 meters, the RMSEr value for the Delivery 2 area is 0.064 meters, with a ACCr of 0.11 meters at the 95% confidence level.

Block03:Based on a flying altitude of 400 meters, an IMU error of 0.006 decimal degrees, and a GNSS positional error of 0.015 meters, the RMSEr value for the Delivery 3 area is 0.076 meters, with a ACCr of 0.13 meters at the 95% confidence level. The project specification requires horizontal positions to be accurate to 1.0m(RMSE).

Block04:Based on a flying altitude of 400 meters, an IMU error of 0.003 decimal degrees, and a GNSS positional error of 0.015 meters, the RMSEr value for the Delivery 4 area is 0.040 meters, with a ACCr of 0.07 meters at the 95% confidence level.

Block05: Based on a flying altitude of 400 meters, an IMU error of 0.003 decimal degrees, and a GNSS positional error of 0.015 meters, the RMSEr value for the Delivery 5 area is 0.040 meters, with a ACCr of 0.07 meters at the 95% confidence level.

Block06: Based on a flying altitude of 400 meters, an IMU error of 0.005 decimal degrees, and a GNSS positional error of 0.015 meters, the RMSEr value for the Delivery 6 area is 0.064 meters, with a ACCr of 0.11 meters at the 95% confidence level.

Block07:Based on a flying altitude of 400 meters, an IMU error of 0.005 decimal degrees, and a GNSS positional error of 0.015 meters, the RMSEr value for the Delivery 7 area is 0.064 meters, with a ACCr of 0.11 meters at the 95% confidence level.

Block08: Based on a flying altitude of 400 meters, an IMU error of 0.005 decimal degrees, and a GNSS positional error of 0.015 meters, the RMSEr value for the Delivery 8 area is 0.064 meters, with a ACCr of 0.11 meters at the 95% confidence level.

Block09: Based on a flying altitude of 400 meters, an IMU error of 0.006 decimal degrees, and a GNSS positional error of 0.023 meters, the RMSEr value for the Delivery 9 area is 0.078 meters, with a ACCr of 0.14 meters at the 95% confidence level.

All accuracy values are reported at 95% confidence level.

Block01 dataset Non-Vegetated Vertical Accuracy (NVA) tested 0.049 m against the derived bare earth DEM in open terrain using 10 ground check points, based on RMSEz (0.025 m) x 1.9600. Vegetated Vertical Accuracy (VVA) tested 0.164 m at the 95th percentile against the derived bare earth DEM using 9 landclass points. Block01 tested 0.157 m against the derived topobathymetric bare earth DEM using 34 submerged check points, based on RMSEz (0.080 m) x 1.9600.

Block02 dataset NVA tested 0.072 m against the derived bare earth DEM in open terrain using 14 ground check points, based on RMSEz (0.037 m) x 1.9600. VVA tested 0.154 m at the 95th percentile against the derived bare earth DEM using 14 landclass points. Block02 tested 0.116 m vertical accuracy against the derived topobathymetric bare earth DEM using 89 submerged check points, based on RMSEz (0.059 m) x 1.9600.

Block03 dataset NVA tested 0.041 m against the derived bare earth DEM in open terrain using 19 ground check points, based on RMSEz (0.021 m) x 1.9600. VVA tested 0.123 m at the 95th percentile against the derived bare earth DEM using 20 landclass points. Block03 tested 0.174 m vertical accuracy against the derived topobathymetric bare earth DEM using 60 submerged check points, based on RMSEz (0.089 m) x 1.9600.

Block04 dataset NVA tested 0.047 m against the derived bare earth DEM in open terrain using 8 ground check points, based on RMSEz (0.024 m) x 1.9600. VVA tested 0.089 m at the 95th percentile against the derived bare earth DEM using 3 landclass points. Block04 tested 0.140 m vertical accuracy against the derived topobathymetric bare earth DEM using 34 submerged check points, based on RMSEz (0.071 m) x 1.9600.

Block05 dataset NVA tested 0.048 m against the derived bare earth DEM in open terrain using 27 ground check points, based on RMSEz (0.025 m) x 1.9600. VVA tested 0.093 m at the 95th percentile against the derived bare earth DEM using 3 landclass points. Block05 tested 0.160 m vertical accuracy against the derived topobathymetric bare earth DEM using 308 submerged check points, based on RMSEz (0.082 m) x 1.9600.

Block06 dataset NVA tested 0.084 m against the derived bare earth DEM in open terrain using 27 ground check points, based on RMSEz (0.043 m) x 1.9600. VVA tested 0.242 m at the 95th percentile against the derived bare earth DEM using 14 landclass points. Block06 tested 0.195 m vertical accuracy against the derived topobathymetric bare earth DEM using 165 submerged check points, based on RMSEz (0.100 m) x 1.9600.

Block07 dataset NVA tested 0.049 m against the derived bare earth DEM in open terrain using 24 ground check points, based on RMSEz (0.025 m) x 1.9600. VVA tested 0.195 m at the 95th percentile against the derived bare earth DEM using 17 landclass points. Block07 tested 0.144 m vertical accuracy against the derived topobathymetric bare earth DEM using 124 submerged check points, based on RMSEz (0.074 m) x 1.9600.

Block08 dataset NVA tested 0.068 m against the derived bare earth DEM in open terrain using 23 ground check points, based on RMSEz (0.034 m) x 1.9600. VVA tested 0.197 m at the 95th percentile against the derived bare earth DEM using 22 landclass points. Block08 tested 0.135 m vertical accuracy against the derived topobathymetric bare earth DEM using 123 submerged check points, based on RMSEz (0.069 m) x 1.9600.

Block09 dataset NVA tested 0.067 m against the derived bare earth DEM in open terrain using 34 ground check points, based on RMSEz (0.034 m) x 1.9600. VVA tested 0.159 m at the 95th percentile against the derived bare earth DEM using 18 landclass points. Block09 tested 0.244 m vertical accuracy against the derived topobathymetric bare earth DEM using 11 submerged check points, based on RMSEz (0.124 m) x 1.9600.

Block01 is comprised of 36 - 5000 m x 5000 m DEM tiles.

Block02 is comprised of 77 - 5000 m x 5000 m DEM tiles.

Block03 is comprised of 107 - 5000 m x 5000 m DEM tiles.

Block04 is comprised of 61 - 5000 m x 5000 m DEM tiles.

Block05 is comprised of 62 - 5000 m x 5000 m DEM tiles.

Block06 is comprised of 79 - 5000 m x 5000 m DEM tiles.

Block07 is comprised of 101 - 5000 m x 5000 m DEM tiles.

Block08 is comprised of 126 - 5000 m x 5000 m DEM tiles..

Block09 is comprised of 175 - 5000 m x 5000 m DEM tiles..

Not applicable

Data is backed up to tape and to cloud storage.