Data Management Plan (Deprecated)

Product: Classified light detection and ranging (lidar) LAS 1.4 files formatted to 4,474 1500 ft x 1500 ft tiles.

In July 2018, Quantum Spatial (QSI) was contracted by the United States Geological Survey (USGS) to collect Light Detection and Ranging (LiDAR) data in the summer of 2018 for several areas of interest (AOIs), comprising the North Slope Borough Communities 3DEP LiDAR project in Alaska. Data were collected to aid USGS in assessing the topographic and geophysical properties of the study area, to support its mission to gather high quality 3D elevation data over the state of Alaska.

Due to inclement weather and the short acquisition timeframe in Alaska, QSI was able to collect LiDAR data in eight out of the eleven contracted AOIs in the 2018 acquisition season: Atqasuk, Barrow North, Barrow South, Barrow Village, Deadhorse, Kaktovic, Nuiqsut and Wainwright. Data collection for the remaining AOIs: Anaktuvuk Pass, Point Lay, and Point Hope was then completed in the summer of 2019.

Dataset Description: The North Slope Borough 3DEP LiDAR project called for the planning, acquisition, and processing of LiDAR data collected at an aggregate nominal pulse spacing (ANPS) of either 0.35 meters or 0.70 meters depending on area. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base LiDAR Specification, Version 1.3. The data was developed based on the NAD83(2011) horizontal datum and NAVD88 (GEOID12B) vertical datum. Data was projected in the appropriate Alaska State Plane Zone for its location.

Process Steps:

• 2019-04-30 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 geoid 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.
• 2019-04-30 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 final NVA for the project using ground control quality check points.
• The NOAA Office for Coastal Management (OCM) downloaded this data set from this USGS site: ftp://rockyftp.cr.usgs.gov/vdelivery/Datasets/Staged/Elevation/LPC/Projects/AK_NorthSlopeBorough_2018_B18/ All 14 subfolders, or blocks, were downloaded. The total number of files downloaded and processed was 5,467. OCM determined the following information regarding the USGS Quality Level (QL) and Alaska State Plane Zone projection for each block: ------------------------------------------------------------------------------------------------------ "NAD83(2011) / Alaska zone 4 (ftUS)" B9 = QL1 B12 = QL2 B2 = QL1 B6 (2 AOIs) = QL2 ------------------------------------------------------------------------------------------------------ "NAD83(2011) / Alaska zone 2 (ftUS)" B1 = QL1 B5 = QL2 -------------------------------------------------------------------------------------------------------- "NAD83(2011) / Alaska zone 6 (ftUS)" B3 = QL1 (2 AOIs) B7 (3 AOIs) = QL2 ----------------------------------------------------------------------------------------------------- "NAD83(2011) / Alaska zone 7 (ftUS)" B4 = QL1 B8 = QL2 B10 = QL1 B13 = QL2 ---------------------------------------------------------------------------------------------------- "NAD83(2011) / Alaska zone 8 (ftUS)" B11 = Ql1 B14 = QL2 The data were in the above Alaska State Plane zones, (NAD83 2011), U.S. Feet coordinates and NAVD88 (Geoid12B) elevations in U.S Feet. The data were classified as: 1 - Unclassified, 2 - Ground, 3- Low Vegetation (0.5 - 2 meters), 4 - Medium Vegetation (2 - 6 meters), 5 - High Vegetation (6+ meters), 6 - Buildings, 7 - Noise, 9 - Water, 17 - Bridge Decks, 20 - Ignored Ground, 21 - Snow. OCM processed all classifications of points to the Digital Coast Data Access Viewer (DAV). For this mission, only folders Blocks 1, 2, 3, 4, 9, 10 and 11 were processed, as these were the QL1 files. OCM performed the following processing on the data for Digital Coast storage and provisioning purposes: 1. An internal OCM script was run to check the number of points by classification and by flight ID and the gps and intensity ranges. 2. Internal OCM scripts were run on the laz files to convert from orthometric (NAVD88) elevations to ellipsoid elevations using the Geoid12B model, to convert from Alaska State Plane (NAD83 2011), U.S. Feet coordinates 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 or custom downloads

Data is backed up to tape and to cloud storage.