Data Management Plan (Deprecated)

The Project data set consists of the Classified Point Cloud. The Geographical Extent of this dataset extends to the entirety of the CA_UpperSouthAmerican_Eldorado_2019_B19 boundary, approximately 2,275 square miles of the AOIs. Ground Conditions: water at normal levels; no unusual inundation; no snow; leaf off. How the Withheld Points are Identified: Withheld (ignore) points were identified in the files using the standard LAS Withheld bit.

The USGS/BLM contracted Digital Aerial Solutions, LLC to obtain professional services related to the planning, acquisition and development of Light Detection and Ranging (Lidar) data and derivative products. The task order is for a QL1 LiDAR survey to be collected over Alameda, Alpine, Amador, Calveras, El Dorado, Placer, Sacramento, San Joaquin, Santa Clara and Stanislaus counties in California.

This metadata supports the data entry in the NOAA Digital Coast Data Access Viewer (DAV). For this data set, the DAV is leveraging the Entwine Point Tiles (EPT) hosted by USGS on Amazon Web Services.

Lineage Statement:
The CA Eldorado lidar was ingested into the Data Access Viewer for custom product generation by leveraging USGS hosted Entwine Point Tiles.

Process Steps:

• 2020-02-15 00:00:00 - Aerial LiDAR Acquisition: LiDAR acquisition was done using Carson City Airport (KCXP),Placerville Airport(JS4761),Tracy Municipal Airport (KTCY) and Columbia Airport(O22). DAS used two dedicated GPS base station located at the respective airports to support the aerial LiDAR acquisition. DAS used Leica’s Terrian Mapper LiDAR Sensor (SN90524) for the acquisition. The project consisted of 399 flightlines totaling 8,871.32 nautical miles. The acquisition was completed in 22 lifts on October 21st - November 2nd,2019 and March 5th, 2020. Ground Control Survey: A survey was performed to support the acquisition of Light Detection and Ranging (LiDAR). The control network involved a total of One Hundred Sixty-Three (163) check points (94 NVA + 69 VVA). The points were a combination of the following ground cover classification: Open Terrain, Urban Terrain, Bare Earth, High Grass, and Low Trees. All field survey observations were conducted between October 22, 2019 and it was completed October 30, 2019 with Leica GPS GS15 and 1200 equipment.
• 2020-01-24 00:00:00 - LiDAR Data Processing: Inertial Explorer 8.9 software was used to compute inertial solution file (*.sol) for each mission using ground GPS base station. The resulting solution was checked to ensure a minimum accuracy of +/- 0.05m, combined separation, for horizontal and vertical positions. Inertial Explorer methodology integrates Inertial Navigation Solution by processing the GPS data and Inertial Measurement Unit (IMU). The software applies the reference lever arms for the GPS and IMU during the process to determine the trajectory (position and orientation) of the LiDAR sensor during the acquisition mission. Inertial Explorer generated graphical results was reviewed to ensure that the IMU data was healthy. These results are found in Appendix D. Raw LiDAR sensor ranging data and the final solution sensor trajectory (*.sol), from Inertial Explorer, were processed in Leica’s HxMap software to produce LiDAR point cloud swath for each flight line in LAS version 1.4 file format. Quality control of the swath point cloud was performed to validate proper functioning of the sensor system, full coverage of the project area and point density of the LiDAR data. Swath point clouds were assigned unique file source identification. The data was found to be complete and consistent with the sensor calibration parameters.
• 2020-01-25 00:00:00 - LiDAR Calibration: HxMap is the common workflow platform for Leica airborne sensors. The processing workflow involves; Ingest, Block Creation, LiDAR Matching, Quality Assurance (QA) and Product Generation. LiDAR is processed in HxMap by generating point clouds from raw sensor data during the Ingest step. Noise filtering, sensor installation calibration and atmospheric condition parameters are also applied during the ingest process. Once all data is processed through ingest, they are assembled into a block for LiDAR Matching. The LiDAR Matching step resolves LiDAR registration errors which remain in the point clouds after sensor and installation calibration parameters are applied in the ingest step. QA tool is run on the Block after LiDAR Matching to verify quality of results. QA results are reviewed to ensure that, 95% of patches less thand 5cm for Vertical Scan Direction and Vertical Line Separation. Ground control points are also included to assess absolute accuracy for the point cloud data. LiDAR products are finally generated in the Product Generation step as LAS swaths (LAS 1.4). Vertical (Z) shift (calculated from QA step) is also applied during the product generation.
• Original point clouds in LAS/LAZ format were restructured as Entwine Point Tiles and stored on Amazon Web Services. The data were re-projected horizontally to WGS84 Web Mercator (EPSG 3857). Vertically, the data were converted to meters and no changes were made to the vertical datum (NAVD88 GEOID12B; EPSG 5703).
• 2022-02-16 00:00:00 - References to the entwine point tiles and data reports were ingested into the Digital Coast Data Access Viewer. No changes to the data were made at this point. The Data Access Viewer will access the point cloud as it resides on AWS under the usgs-lidar-public container.

Data is available online for bulk and custom downloads.

Data is backed up to tape and to cloud storage.