NV5 Geospatial 20221231 Lidar Point Cloud Product: Classified LAS 1.4 files, formatted to 1000 individual 1500m x 1500m tiles covering the Alaska Native Villages Lidar project area. Geographic Extent: This dataset and derived products encompass an area covering approximately 100,000 acres of Alaska. Dataset Description: The Alaska Native Villages Lidar Lidar project called for the planning, acquisition, and processing of lidar data collected to QL2. Project specifications are based on the U.S. Geological Survey National Geospatial Program LIDAR Base Specification, Version 2.1. The data was developed based on the NAD83 2011 horizontal datum and the NAVD88 Geoid 12B vertical datum. Data was projected in UTM Zone 3 N, Meters. Lidar data was delivered as calibrated and classified LAS 1.4 files. Non-Vegetated Vertical Accuracy (NVA) was assessed using 17 check points located on bare earth in clear, unobstructed areas. Vegetated Vertical Accuracy (VVA) was assessed using 19 check points in Tall Grass and Shrub landcover types. Single swath nominal pulse spacing (NPS) was designed to be 0.707 at nadir. Aggregate Nominal Pulse Spacing (ANPS) was calculated to be 0.457 using all valid first return points. Derived products include: Intensity Imagery, Hydro-flattened Bare Earth Digital Elevation Models (DEMs), Highest Hit Digital Surface Models (DSMs), and 3D waters edge breaklines. Ground Condition: Ground condition was free of snow and acquisition occured free of smoke, fog and cloud cover. The purpose of the lidar data was to produce a high accuracy 3D dataset that meets all necessary standards laid out by the 3D Elevation Program and the Alaska Native Villages Lidar contract. The lidar point cloud data were used to create classified lidar LAS files, intensity images, hydro-flattened DEMs, highest hit DSMs, and 3D breaklines of rivers and lakes within the study area. USGS Contract No. Example CONTRACTOR: NV5 Geospatial Ground Control Points were acquired and calibrated by DOWL All lidar data acquisition, calibration, and follow-on processing were completed by NV5 Geospatial U.S. Geological Survey National Geospatial Program LIDAR Base Specification, Version 2.1 Riegl 1560ii-S 15 0.707 2 0.457 4.78 2500 145 58.5 uniform point spacing 757 3 0.57 1064 1 0.23 2800 20 Geoid 12B 0.235 m 0.093 m 17 1.4 6 Withheld (ignore) points are identified in these files using the standard LAS Withheld bit. Swath "overage" points were identified in these files using the standard LAS overlap bit. 16 1 Processed, but Unclassified 2 Bare earth ground 7 Low Noise 9 Water 17 Bridge Decks 18 High Noise 20 Ignored Ground Near Breaklines 20220811 20221014 ground condition Complete None Planned 1 1 1 1 1 1 1 1 none model LAS Point Cloud remote sensing Elevation data Lidar none Alaska No restrictions apply to these data. None. However, users should be aware that temporal changes may have occurred since this dataset was collected and that some parts of these data may no longer represent actual surface conditions. Users should not use these data for critical applications without a full awareness of its limitations. Acknowledgment of the U.S. Geological Survey would be appreciated for products derived from these data. LiDAR Mapping Suite 2.4, Applanix PosPac 7.1, Microstation CONNECT version, TerraScan Version 23, TerraModeler Version 21, TerraMatch Version 22, ESRI ArcGIS 10.3, Windows 10 Operating Classified LAS files were tested by NV5 Geospatial for vertical accuracy. All data is seamless from one tile to the next, no gaps or no data areas. These LAS data files include all data points collected. No points have been removed or excluded. A visual qualitative assessment was performed to ensure data completeness. No void areas or missing data exist. The raw point cloud is of good quality and data passes Non-Vegetated Vertical Accuracy specifications. This data set was produced to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a 0.235 (m) RMSEx / RMSEy Horizontal Accuracy Class which equates to the Positional Horizontal Accuracy = +/- 0.407 m at a 95% confidence level. 0.407 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. Using a flying altitude of 2500 meters, an IMU error of 0.003 decimal degrees, and a GNSS positional error of 0.023 meters, this project was compiled to meet 0 meters horizontal accuracy at the 95% confidence level. This data set was produced to meet ASPRS Positional Accuracy Standard for Digital Geospatial Data (2014) for a 10-cm RMSEz Vertical Accuracy Class. The NVA was tested with 17 independent check points located in open terrain and distributed throughout the project as feasible. These check points were not used in the calibration or post processing of the lidar point cloud data. Specifications for this project require that the NVA be 0.196 meters or better AccuracyZ at 95% confidence level. 0.093 m The 17 independent NVA check points were surveyed using the closed level loop technique. Elevations interpolated from the unclassified lidar surface were compared to the elevation values of the surveyed NVA check points. The RMSE was computed to be 0.047 m meters resulting in an AccuracyZ at the 95% confidence level of 0.093 m meters. NVA AccuracyZ has been tested and meets the required 0.196 meter NVA at 95% confidence level using (RMSEz * 1.9600) for the unclassified lidar point cloud as defined by the National Standards for Spatial Data Accuracy (NSSDA) and herein reported using National Digital Elevation Program (NDEP)/ASPRS Guidelines. 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 12B correction. 5. Import raw laser points into manageable blocks 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. Alaska Native Villages Lidar Ground Control 20221231 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, VVA, and density information for the project using ground control quality check points. 20221231 Vector Point 100,000,000,000 Universal Transverse Mercator 3 coordinate pair 0.01 0.01 Meters North American Datum of 1983 2011 GRS_1980 6378137.0 298.257223563 North American Vertical Datum of 1988 Geoid 12B 0.01 Meters Explicit elevation coordinate included with horizontal coordinates 20221231 20221231 NV5 Geospatial mailing and physical

2014 Merrill Field Drive

Anchorage AK 99501 USA 907-272-4495 FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998 None None None Unclassified None None None