Data Management Plan

Product: Lidar based digital elevation model (DEM) data tiles for ground classified points.

Geographic Extent: Approximately 21,453 square miles across South Carolina;

Block 1 (Lot 6 QL2) - approximately 3,583 square miles in Anderson, Cherokee, Greenville, Laurens, Newberry, Oconee, Pickens, Spartanburg, and Union counties

Block 2 (Lot 7 QL1) - approximately 950 square miles in Greenville and Lexington counties

Block 3 (Lot 7 QL2) - approximately 3435 square miles in Abbeville, Aiken, Anderson, Edgefield, Greenwood, Laurens, McCormick, Newberry, Oconee, and Saluda counties

Block 4 (Lot 8 QL1) - approximately 135 square miles in Aiken and Edgefield counties

Block 5 (Lot 8 QL2) - approximately 5,775 square miles in Aiken, Allendale, Bamberg, Barnwell, Calhoun, Chester, Chesterfield, Clarendon, Colleton, Edgefield, Fairfield, Hampton, Kershaw, Lancaster, Lee, Lexington, McCormick, Newberry, Orangeburg, Richland, Saluda, and Sumter counties

Block 6 (Lot 9 QL2) - approximately 7,255 square miles in Bamberg, Beaufort, Berkeley, Charleston, Chesterfield, Clarendon, Colleton, Darlington, Dillon, Dorchester, Florence, Georgetown, Hampton, Horry, Jasper, Kershaw, Lee, Marion, Marlboro, Orangeburg, Sumter, and Williamsburg counties

Block 7 (Lot 9 QL1) - approximately 689 square miles in Beaufort, Berkeley, Charleston, Colleton, Darlington, Dorchester, Florence counties

Dataset Description: The SC Savannah Pee Dee 2019 B19 lidar project called for the planning, acquisition, processing, and production of derivative products of QL 1 and QL2 lidar data to be collected at a nominal pulse spacing (NPS) of 0.35 and 0.71 meters. Project specifications were based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.3. The data was developed based on a horizontal datum/projection of NAD83 (2011) State Plane South Carolina (FIPS 3900) International Feet (EPSG 6570), and a vertical datum of NAVD88 (GEOID18) US Survey Feet. Lidar data was delivered as processed LAS 1.4 files formatted to individual 5,000-Int'l. foot x 5,000-Int'l. foot tiles.

Ground Conditions: Lidar was collected January through March 2020 while no snow was on the ground and rivers were at or below normal levels. In order to post process the lidar data to meet task order specifications and meet ASPRS vertical accuracy guidelines, Woolpert established ground control points that were used to calibrate the lidar to known ground locations established throughout the project area. Additional independent accuracy checkpoints were collected and used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data.

Lineage Statement:
The NOAA Office for Coastal Management (OCM) ingested references to the USGS Cloud Optimized GeoTIFF files hosted on Amazon Web Services (AWS) into the Digital Coast Data Access Viewer (DAV). The DAV accesses the DEM as it resides on AWS under the prd-tnm bucket.

Process Steps:

• 2020-09-04 00:00:00 - Lidar Point Cloud Classification: The point cloud underwent a classification process to determine bare-earth points and non-ground points utilizing "first and only" as well as "last of many" lidar returns. This process determined Processed, but Unclassified (Class 1), Bare Earth Ground (Class 2), Low Noise (Class 7), Water (Class 9), Bridge Decks (Class 17), High Noise (Class 18), and Ignored Ground (Class 20). The bare-earth (Class 2 - Ground) lidar points underwent a manual QA/QC step to verify the quality of the DEM as well as a peer-based QC review. This included a review of the DEM surface to remove artifacts and ensure topographic quality. After the bare-earth surface is finalized, it is then used to generate all hydro-breaklines through a semi-automated process. All ground (Class 2) lidar data inside of the Lake Pond and Double Line Drain hydro flattening breaklines were then classified to water (Class 9) using TerraScan/LP360 macro functionality. A buffer of 0.7 meters was also used around each hydro-flattened feature to classify these ground (Class 2) points to Ignored Ground (Class 20). All Lake Pond Island and Double Line Drain Island features were checked to ensure that the ground (Class 2) points were reclassified to the correct classification after the automated classification was completed. All overlap data was processed through automated functionality provided by TerraScan to classify the overlapping flight line data to approved classes by USGS. The overlap data was classified using standard LAS overlap bit. These classes were created through automated processes only and were not verified for classification accuracy. Due to software limitations within TerraScan, these classes were used to trip the withheld bit within various software packages. These processes were reviewed and accepted by USGS through numerous conference calls and pilot study areas. All data was manually reviewed and any remaining artifacts removed using functionality provided by TerraScan and TerraModeler. Global Mapper was used as a final check of the bare earth dataset. GeoCue was then used to create the deliverable industry-standard LAS files. Woolpert proprietary software and LP360 was used to perform final statistical analysis of the classes in the LAS files, on a per tile level to verify final classification metrics and full LAS header information.
• 2020-09-01 00:00:00 - Hydro-Flattened Digital Elevation Models (DEMs): Class 2 (ground) lidar points in conjunction with the hydro breaklines as well bridge breaklines were used to create a 2-foot hydro-flattened bare-earth raster DEM. Using automated scripting routines within ArcMap, a GeoTIFF file was created for each tile. Each surface is reviewed using Global Mapper to check for any surface anomalies or incorrect elevations found within the surface.
• 2021-12-15 00:00:00 - The NOAA Office for Coastal Management (OCM) extracted the tiff file URL references and ingested them into the NOAA Digital Coast Data Access Viewer (DAV). No changes were made to the data. The DAV will access the DEM as it resides on Amazon Web Services (AWS) under the pr-tnm container. (Citation: USGS GeoTiff files on AWS)

Data is available online for bulk and custom downloads.

Data is backed up to tape and to cloud storage.