Atlantic Unpublished Material vector format None Available None Available This data set contains ESRI shapefiles for all closed hydro features in the 2016 Alabama 25 County lidar area of interest (AOI). Features were collected using the spec of 2 acre minimum size limits for closed features. The data set was then ingested into an ESRI 3D terrain model to support the creation of hydro enforced Lidar derived products. USGS NGTOC task order G17PD00243 required Spring 2017 LiDAR surveys to be collected over 18,845 square miles covering part or all of 25 counties in Alabama. These counties are Autauga, Baldwin, Barbour, Bullock, Butler, Chambers, Cherokee, Clarke, Conecuh, Covington, Crenshaw, Elmore, Etowah, Henry, Houston, Lamar, Limestone, Macon, Monroe, Pike, Randolph, Russell, Shelby, Tallapoosa, and Winston. Aerial LiDAR data for this task order was planned, acquired, processed, and produced at an aggregate nominal pulse spacing (ANPS) of 0.7 meters and in compliance with USGS National Geospatial Program LiDAR Base Specification version 1.2. Isolated gaps in GPS data were identified in several missions covering this project. As both, the IMU data and pulse data, were present across these gaps, using the fixed positions of the GPS on either end, the aircraft velocity across the gaps, and the IMU data, LiDAR calibration staff were able to reach an effective solution to address the GPS voids. Because these gaps were not uniform in size or correction, this extended the iterative LiDAR calibration efforts on this project. Subsequent rigorous data checking confirmed adequate results to meet the required accuracy specs. The USGS QA Team already reviewed affected data (blocks) for this project and found no QA/QC discrepancies to report regarding those gaps. Geographic Extent: This data set is consisting of lidar point cloud, classified lidar, digital elevation model, and lidar intensity images which all pieces encompasses the 2016 Alabama 25 County lidar (Pilot) area of interest (AOI), approximately 18,845 square miles or 1,572 square kilometers. Data set Description: This data set consists of lidar point cloud LAS swath files and tiled LAS files. Each LAS file contains lidar point information, which has been calibrated, controlled, and classified. Each file represents a separate swath of lidar. 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. Class Code:1 Class Item:Unclassified Class Code:2 Class Item:Ground Class Code:7 Class Item:Low Noise Class Code:9 Class Item:Water Class Code:10 Class Item:Ignored Ground Class Code:17 Class Item:Bridges Class Code:18 Class Item:High Noise The primary purpose of the lidar survey was to establish measurements of the bare earth surface, as well as top surface feature data for providing geometric inputs for modeling, other numerical modeling and economic related assessments. All lidar data was acquired, calibrated, and used in the creation of lidar derived products by Atlantic. 20161229 0800 20191112 1200 ground condition Complete As needed -88.296640 -84.820970 34.999031 30.208650 None Elevation Data Lidar DEM Intensity Image None Alabama Autauga County Baldwin County Barbour County Bullock County Butler County Chambers County Cherokee County Clarke County Conecuh County Covington County Crenshaw County Elmore County Etowah County Henry County Houston County Lamar County Limestone County Macon County Monroe County Pike County Randolph County Russell County Shelby County Tallapoosa County Winston County No restrictions apply to this data the data represented is the result of data collection and processing per contract specifications and indicates the general existing conditions at the time of the data collection. As such, it is only valid for its intended use, content, time, and accuracy specifications. The user is responsible for the results of any application of the data for other than its intended purpose. 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 the limitations of the data. Acknowledgement of USGS would be appreciated for products derived from these data.The data represented is the result of data collection and processing per contract specifications and indicates the general existing conditions at the time of the data collection. As such, it is only valid for its intended use, content, time, and accuracy specifications. The user is responsible for the results of any application of the data for other than its intended purpose. USGS Dan Vincent Project Manger mailing and physical address

1400 Independence Road

Rolla MO 65401 USA 573-308-3689 dvinc@usgs.gov Monday through Friday 8:00 AM to 4:00 PM If unable to reach the contact by telephone, please send an email. You should get a response within 24 hours. None Available Contact USGS None Available Contact USGS None Available Contact USGS CloudPro 1.2.0 Build 85620; GeoCue Version 2014.1.21.2; Windows 7 Operating System \\lidarsrv\GC_Warehouse_5\80658\30\*.las 184 GB All lidar data and lidar derived data covers the entire 18,845 square miles area of interest for the pilot area. All lidar point cloud tiles show no edge artifacts or mismatches from tile to tile. Void areas (i.e. areas outside the project boundary but within the tiling scheme) are coded using a unique NODATA value. This value is identified in the appropriate location within the file header. Data cover the entire area specified for this project. The raw LAS data files included all data points collected. No points have been removed or excluded. A visual qualitative assessment was performed to ensure data completeness. The raw point cloud is of good quality and data passes Fundamental Vertical Accuracy specifications.Void areas (i.e., areas outside the project boundary but within the tiling scheme) are coded using a unique NODATA value. This value is identified in the appropriate location within the file header. Vertical Accuracy of the point cloud and bare-earth lidar data was assessed and reported in accordance with the ASPRS Positional Accuracy Standards for Digital Geospatial Data; Required Vegetated Vertical Accuracy (VVA): 29.4cm. Required Non Vegetated Vertical Accuracy (NVA) : 19.6cm Required Non-Vegetated Vertical Accuracy (NVA) for the Point Cloud:0.196 Required Vegetated Vertical Accuracy (VVA): 0.294 .0817 This data set was tested to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a 10.0 (cm) RMSEz Vertical Accuracy Class. Actual NVA accuracy of the bare-earth was found to be RMSEz = .817m, equating to +/- .1601m at 95% confidence level. .0092 This data set was tested to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a 10.0 (cm) RMSEz Vertical Accuracy Class. Actual VVA accuracy was found to be RMSEz = .1192m, equating to +/-.2335m at the 95th percentile. Ground Control Survey A total of 761 ground survey points were collected in support of this project, including 136 LiDAR Control Points (LCP), 340 Non-vegetated Vertical Accuracy (NVA) and 285 Vegetated Vertical Accuracy (VVA). Point cloud data accuracy was tested against a Triangulated Irregular Network (TIN) constructed from LiDAR points in clear and open areas. A clear and open area can be characterized with respect to topographic and ground cover variation such that a minimum of five (5) times the Nominal Pulse Spacing (NPS) exists with less than 1/3 of the RMSEZ deviation from a low-slope plane. Slopes that exceed ten (10) percent were avoided. Each land cover type representing ten (10) percent or more of the total project area were tested and reported with a VVA. In land cover categories other than dense urban areas, the tested points did not have obstructions forty-five (45) degrees above the horizon to ensure a satisfactory TIN surface. The VVA value is provided as a target. It is understood that in areas of dense vegetation, swamps, or extremely difficult terrain, this value may be exceeded. The NVA value is a requirement that must be met, regardless of any allowed “busts” in the VVA(s) for individual land cover types within the project. Checkpoints for each assessment (NVA and VVA) are required to be well-distributed throughout the land cover type, for the entire project area. 20191110 0800 Atlantic Jochen A. Floesser Vice President Production Manager mailing and physical

2223 Drake Ave. SW Suite 200

Huntsville AL 35805 USA 256-971-9991 256-971-1154 Jochen.Floesser@atlantic.tech Aerial Lidar Acquisition: Atlantic acquired 882 passes of the AOI as a series of perpendicular and/or adjacent flight-lines executed in 83 flight missions conducted between December 28, 2016 and November 10, 2019. Onboard differential Global Navigation Satellite System (GNSS) unit(s) recorded sample aircraft positions at 2 hertz (Hz) or more frequency. LiDAR data was only acquired when a minimum of six (6) satellites were in view. 20191110 Atlantic Jochen A. Floesser Vice President Production Manager mailing and physical

2223 Drake Ave. SW Suite 200

Huntsville AL 35805 USA 256-971-9991 256-971-1154 Jochen.Floesser@atlantic.tech LiDAR Point Cloud Generation Atlantic utilized Leica software products to download the IPAS ABGNSS/IMU data and raw laser scan files from the airborne system. Waypoint Inertial Explorer is used to extract the raw IPAS ABGNSS/IMU data, which is further processed in combination with controlled base stations to provide the final Smoothed Best Estimate Trajectory (SBET) for each mission. The SBETs are combined with the raw laser scan files to export the LiDAR ASCII Standard (*.las) formatted swath point clouds. 20191110 Atlantic Jochen A. Floesser Vice President Production Manager mailing and physical

2223 Drake Ave. SW Suite 200

Huntsville AL 35805 USA 256-971-9991 256-971-1154 Jochen.Floesser@atlantic.tech Smooth Surface Repeatability (Interswath) Departures from planarity of first returns within single swaths in non-vegetated areas were assessed at multiple locations with hard surface areas (parking lots or large rooftops) inside the project area. Each area was evaluated using signed difference rasters (maximum elevation – minimum elevation) at a cell size equal to 2 x ANPS, rounded to the next integer. 20191110 0800 Atlantic Jochen A. Floesser Vice President Production Manager mailing and physical

2223 Drake Ave. SW Suite 200

Huntsville AL 35805 USA 256-971-9991 256-971-1154 Jochen.Floesser@atlantic.tech LiDAR Calibration Using a combination of GeoCue, TerraScan and TerraMatch; overlapping swath point clouds are corrected for any orientation or linear deviations to obtain the best fit swath-to-swath calibration. Relative calibration was evaluated using advanced plane-matching analysis and parameter corrections derived. This process was repeated interactively until residual errors between overlapping swaths, across all project missions, was reduced to ≤2cm. A final analysis of the calibrated LiDAR is preformed using a TerraMatch tie line report for an overall statistical model of the project area. Individual control point assessments for this project can be found in Section VI of this report. Upon completion of the data calibration, a complete set of elevation difference intensity rasters (dZ Orthos) are produced. A user-defined color ramp is applied depicting the offsets between overlapping swaths based on project specifications. The dZ orthos provide an opportunity to review the data calibration in a qualitative manner. Atlantic assigns green to all offset values that fall below the required RMSDz requirement of the project. A yellow color is assigned for offsets that fall between the RMSDz value and 1.5x of that value. Finally, red values are assigned to all values that fall beyond 1.5x of the RMSDz requirements of the project. 20191110 0800 Atlantic Jochen A. Floesser Vice President Production Manager mailing and physical

2223 Drake Ave. SW Suite 200

Huntsville AL 35805 USA 256-971-9991 256-971-1154 Jochen.Floesser@atlantic.tech Multiple automated filtering routines are applied to the calibrated LiDAR point cloud identifying and extracting bare-earth and above ground features. GeoCue, TerraScan, and TerraModeler software was used for the initial batch processing, visual inspection and any manual editing of the LiDAR point clouds. Atlantic utilized collected breakline data to preform classification for classes 9 (Water) and 10 (Ignored Ground). Code Description 1 Processed, but unclassified 2 Bare-earth ground 7 Low Noise (low, manually identified, if necessary) 9 Water 10 Ignored Ground (Breakline Proximity) 17 Bridge Decks 18 High Noise (high, manually identified, if necessary) 20191110 Atlantic Jochen A. Floesser Vice President Production Manager mailing and physical

2223 Drake Ave. SW Suite 200

Huntsville AL 35805 USA 256-971-9991 256-971-1154 Jochen.Floesser@atlantic.tech Lidar Intensity Imagery Creation: All lidar intensity imagery was created from the final calibrated and classified lidar point cloud. Intensity images were produced from all classified points and are posted to a 1 meter cell size. Intensity images were cut to match the tile index and have corresponding names to match tile names. 20191110 Atlantic Jochen A. Floesser Vice President Production Manager mailing and physical

2223 Drake Ave. SW Suite 200

Huntsville AL 35805 USA 256-971-9991 256-971-1154 Jochen.Floesser@atlantic.tech Hydro breaklines were compiled using LiDAR intensity data and surface terrain models of the entire project area. After extraction, all delineated hydro features were validated for monotonicity and vertical variance. This procedure ensures that no points were floating above ground. Hydro-lines were then encoded into the LiDAR surface and used to hydro-enforce/flatten all significant water bodies. These final hydro-lines were then used in the production of bare Earth digital models to hydro flatten significant water bodies. This product was delivered as an ESRI shapefile(s) for the entire project area. 20191110 Atlantic Jochen A. Floesser Vice President Production Manager mailing and physical

2223 Drake Ave. SW Suite 200

Huntsville AL 35805 USA 256-971-9991 256-971-1154 Jochen.Floesser@atlantic.tech 0 vector NAD 1983 2011 UTM Zone 16N 0.9996 -87.0 0.0 500000.0 0.0 coordinate pair 0.000000002220024164500956 0.000000002220024164500956 meter D NAD 1983 2011 GRS 1980 6378137.0 298.257222101 North American Vertical Datum of 1988 (Geoid12B) .01 meters Explicit elevation coordinate included with horizontal coordinates Lidar tiles and associated derived products for USGS Lidar tiles and associated derived products for USGS 20191112 Atlantic Jochen A. Floesser Vice President Production Manager mailing and physical

2223 Drake Ave. SW Suite 200

Huntsville AL 35805 USA 256-971-9991 256-971-1154 Jochen.Floesser@atlantic.tech FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998