Data Management Plan

In May 2017, Quantum Spatial (QSI) was contracted by the United States Geological Survey (USGS) to collect QL1 and QL2 Light Detection and Ranging (LiDAR) data over approximately 1.8 million acres of land for the Fairbanks 3DEP mapping site in Alaska (Task Order G17PD00606). Data were collected to aid USGS in assessing the topographic and geophysical properties of the study area to support the 3DEP mapping initiative.

Geographic Extent: The QL1 area encompasses 248,555 acres and the QL2 area encompasses 1,186,822 acres.

Dataset Description: RAW flight line swaths were processed to create 6,268 classified LAS 1.4 files delineated in 3000 x 3000 ft tiles tiles. Each LAS file contains LiDAR point information, which has been calibrated, controlled, and classified. LAS files have been edited to the extent of the buffered boundary. Additional derived products include intensity images, hydro-flattened DEMs, highest hit surface models, 2ft contours, and 3D breaklines of rivers and lakes within the study area.

Ground Conditions: Data was acquired during conditions with an absence of snow, high water, ground fog and/or clouds below the flight altitudes.

The NOAA Office for Coastal Management (OCM) downloaded 1203 laz files from ftp://rockyftp.cr.usgs.gov/vdelivery/Datasets/Staged/Elevation/LPC/Projects/USGS_LPC_AK_FairbanksNSB_QL1_2017_LAS_2018/ and 6268 laz files from ftp://rockyftp.cr.usgs.gov/vdelivery/Datasets/Staged/Elevation/LPC/Projects/USGS_LPC_AK_FairbanksNSB_QL2_2017_LAS_2018 and processed the data to the Data Access Viewer (DAV) and https.

Hydro and bridge breaklines are also available. These data are available for download at the link provided in the URL section of this metadata record. Please note that these products have not been reviewed by the NOAA Office for Coastal Management (OCM) and any conclusions drawn from the analysis of this information are not the responsibility of NOAA or OCM.

Process Steps:

• 2018-04-16 00:00:00 - LiDAR Pre-Processing: 1. Review flight lines and data to ensure complete coverage of the study area and positional accuracy of the laser points. 2. Resolve kinematic corrections for aircraft position data using kinematic aircraft GPS and static ground GPS data. 3. Develop a smoothed best estimate of trajectory (SBET) file that blends post-processed aircraft position with sensor head position and attitude recorded throughout the survey. 4. Calculate laser point position by associating SBET position to each laser point return time, scan angle, intensity, etc. Create raw laser point cloud data for the entire survey in *.las format. Convert data to orthometric elevations by applying a geoid12b correction. 5. Import raw laser points into manageable blocks (less than 500 MB) to perform manual relative accuracy calibration and filter erroneous points. Classify ground points for individual flight lines. 6. Using ground classified points per each flight line, test the relative accuracy. Perform automated line-to-line calibrations for system attitude parameters (pitch, roll, heading), mirror flex (scale) and GPS/IMU drift. Calculate calibrations on ground classified points from paired flight lines and apply results to all points in a flight line. Use every flight line for relative accuracy calibration. 7. Adjust the point cloud by comparing ground classified points to supplemental ground control points.
• 2018-04-16 00:00:00 - LiDAR Post-Processing: 1. Classify data to ground and other client designated classifications using proprietary classification algorithms. 2. Manually QC data classification 3. After completion of classification and final QC approval, calculate NVA and VVA, and density information for the project using ground control quality check points.
• 2019-01-24 00:00:00 - The NOAA Office for Coastal Management (OCM) downloaded 1203 laz files from ftp://rockyftp.cr.usgs.gov/vdelivery/Datasets/Staged/Elevation/LPC/Projects/USGS_LPC_AK_FairbanksNSB_QL1_2017_LAS_2018/ and 6268 laz files from ftp://rockyftp.cr.usgs.gov/vdelivery/Datasets/Staged/Elevation/LPC/Projects/USGS_LPC_AK_FairbanksNSB_QL2_2017_LAS_2018. The data were in Alaska State Plane, Zone 3 NAD83 2011, US survey feet, coordinates and NAVD88 (Geoid12B) elevations in feet. The data were classified as: 1 - Unclassified, 2 - Ground, 3 - Low vegetation (0.5 - 2 m), 4 - Medium vegetation (2 - 6 m), 5 - High vegetation (greater than 6 m), 6 - Buildings, 7 - Low Noise, 9 - Water, 10 - Ignored Ground, 17 - Bridge Decks. OCM processed all classifications of points to the Digital Coast Data Access Viewer (DAV). Classes available on the DAV are: 1, 2, 3, 4, 5, 6, 7, 9, 10, 17. OCM performed the following processing on the data for Digital Coast storage and provisioning purposes: 1. The LAStools software script lasinfo was run on the laz files to check for errors. 2. An internal OCM script was run to check the number of points by classification and by flight ID, and the gps and intensity ranges. 3. Internal OCM scripts were run on the laz files to convert from orthometric (NAVD88) elevations to ellipsoid elevations using the Geoid 12B model, to convert from elevations in feet to meters, to convert from Alaska State Plane, Zone 3 coordinates in US survey feet to geographic coordinates, to assign the geokeys, to sort the data by gps time and zip the data to database and to http.

Data is available online for bulk and custom downloads.