U.S. Geological Survey 201601 Unknown map Leading Edge Geomatics (LEG) collected 994 square miles in the Virginia counties of Accomack and Northampton. The nominal pulse spacing for this project was 1 point every 0.7 meters. Dewberry used proprietary procedures to classify the LAS according to project specifications: 0-Never Classified, 1-Unclassified, 2-Ground (bare earth points identified as Model Key Points are flagged with the Model Key Point bit), 7-Low Noise, 9-Water, 10-Ignored Ground due to breakline proximity, 17- Bridge Decks, 18-High Noise. Dewberry produced 3D breaklines and combined these with the final LiDAR data to produce seamless hydro flattened DEMs for the project area. The data was formatted according to the VBMP tile naming convention with each tile covering an area of 5,000 feet by 5,000 ft. A total of 1375 LAS tiles and 1310 DEM tiles were produced for the entire project. USGS-NGP Lidar Base Specification V1.2 Riegl 680i 7 0.66 2.25 0.53 3.45 1000 100 60 78 200 5 0.89 1064 0 5.0 1155 50 National Geodetic Survey (NGS) Geoid12A 0.196 0.119 59 0.125 61 0.177 52 1.4 6 Withheld points were 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 0 Calibrated, never classified 1 Processed, but unclassified 2 Bare earth, ground (includes model key point bit for points identified as Model Key Point) 7 Low noise 9 Water 10 Ignored ground due to breakline proximity 17 Bridge decks 18 High noise The purpose of this LiDAR data was to produce high accuracy 3D elevation products, including tiled LiDAR in LAS 1.4 format, 3D breaklines, and 2.5 foot cell size hydro flattened Digital Elevation Models (DEMs). All products follow and comply with USGS Lidar Base Specification Version 1.2. A complete description of this dataset is available in the Final Project Report that was submitted to the U.S. Geological Survey. 20150424 20150424 ground condition Complete As needed -76.093949 -75.227100 38.064707 37.062181 None DTM Elevation Lidar LAS DEM Hydro Flattened Breaklines Bare earth None Virginia Eastern Shores Accomack County Northampton County USA None This data was produced for the U.S. Geological Survey according to specific project requirements. This information is provided "as is". Further documentation of this data can be obtained by contacting: USGS, 1400 Independence Road, Rolla, MO 65401. Telephone (573) 308-3810. U.S. Geological Survey Program Manager mailing and physical address

1400 Independence Road

Rolla MO 65401 USA (573) 308-3810 pemmett@usgs.gov Microsoft Windows 7 Enterprise Service Pack 1; ESRI ArcCatalog 10.3 Data covers the tile scheme provided for the project area. A visual qualitative assessment was performed to ensure data completeness and bare earth data cleanliness. No void or missing data and data passes vertical accuracy specifications. Only checkpoints photo-identifiable in the intensity imagery can be used to test the horizontal accuracy of the LiDAR. Photo-identifiable checkpoints in intensity imagery typically include checkpoints located at the ends of paint stripes on concrete or asphalt surfaces or checkpoints located at 90 degree corners of different reflectivity, e.g. a sidewalk corner adjoining a grass surface. The xy coordinates of checkpoints, as defined in the intensity imagery, are compared to surveyed xy coordinates for each photo-identifiable checkpoint. These differences are used to compute the tested horizontal accuracy of the LiDAR. As not all projects contain photo-identifiable checkpoints, the horizontal accuracy of the LiDAR cannot always be tested. 2.13 ft (65 cm) Lidar vendors calibrate their lidar systems during installation of the system and then again for every project acquired. Typical calibrations include cross flights that capture features from multiple directions that allow adjustments to be performed so that the captured features are consistent between all swaths and cross flights from all directions. Dewberry tested the horizontal accuracy of the LiDAR by comparing photo-identifiable survey checkpoints to the LiDAR Intensity Imagery. As only seventeen (17) checkpoints were photo-identifiable, the results are not statistically significant enough to report as a final tested value but the results of this testing are shown below. Using NSSDA methodology (endorsed by the ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014)), horizontal accuracy at the 95% confidence level (called ACCURACYr) is computed by the formula RMSEr * 1.7308 or RMSExy * 2.448. Actual positional accuracy of this dataset was found to be RMSEx = 0.83 ft (25 cm) and RMSEy = 0.91 ft (28 cm) which equates to +/- 2.13 ft (65 cm) at 95% confidence level. The vertical accuracy of the raw LiDAR swath data was tested by Dewberry prior to any classification of the data. Because swath data is tested prior to any classification, only non-vegetated (open terrain, bare earth and urban) checkpoints are used in this testing. The 59 non-vegetated survey checkpoints were evenly distributed throughout the project area. The vertical accuracy is tested by comparing survey checkpoints to a triangulated irregular network (TIN) that is created from the raw swath points. Checkpoints are always compared to interpolated surfaces created from the LiDAR point cloud because it is unlikely that a survey checkpoint will be located at the location of a discrete LiDAR point. All checkpoints located in non-vegetated terrain were used to compute the Non-vegetated Vertical Accuracy (NVA). Project specifications required a NVA of 0.64 ft (19.6 cm) at the 95% confidence level based on RMSEz (0.33 ft/10 cm) x 1.9600. All checkpoints located in vegetated terrain were used to compute the Vegetated Vertical Accuracy (VVA). Project specifications required a VVA of 0.96 ft (29.4 cm) based on the 95th percentile. 0.39 ft (11.9 cm) This raw swath LiDAR dataset was tested to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a 0.33 ft (10 cm) RMSEz Vertical Accuracy Class. Actual NVA accuracy was found to be RMSEz =0.20 ft (6.10 cm), equating to +/- 0.39 ft (11.9 cm) at 95% confidence level. Data for the Eastern Shores Virginia QL2 LiDAR project was acquired by Leading Edge Geomatics (LEG). The project area included approximately 994 contiguous square miles or 2574.45 square kilometers for the counties of Accomack and Northampton in Virginia. LiDAR sensor data were collected with the Riegl 680i LiDAR system. The data was delivered in the State Plane coordinate system, feet, Virginia South, horizontal datum NAD83, vertical datum NAVD88, Geoid 12a. Deliverables for the project included a raw (unclassified) calibrated LiDAR point cloud, survey control, and a final acquisition/calibration report. The calibration process considered all errors inherent with the equipment including errors in GPS, IMU, and sensor specific parameters. Adjustments were made to achieve a flight line to flight line data match (relative calibration) and subsequently adjusted to control for absolute accuracy. Process steps to achieve this are as follows: Rigorous LiDAR calibration: all sources of error such as the sensor's ranging and torsion parameters, atmospheric variables, GPS conditions, and IMU offsets were analyzed and removed to the highest level possible. This method addresses all errors, both vertical and horizontal in nature. Ranging, atmospheric variables, and GPS conditions affect the vertical position of the surface, whereas IMU offsets and torsion parameters affect the data horizontally. The horizontal accuracy is proven through repeatability: when the position of features remains constant no matter what direction the plane was flying and no matter where the feature is positioned within the swath, relative horizontal accuracy is achieved. Absolute horizontal accuracy is achieved through the use of differential GPS with base lines shorter than 25 miles. The base station is set at a temporary monument that is 'tied-in' to the CORS network. The same position is used for every lift, ensuring that any errors in its position will affect all data equally and can therefore be removed equally. Vertical accuracy is achieved through the adjustment to ground control survey points within the finished product. Although the base station has absolute vertical accuracy, adjustments to sensor parameters introduces vertical error that must be normalized in the final (mean) adjustment. A copy of the final calibrated swaths are maintained in LAS format 1.2 for production utilizing Terrascan software. A second, identical version of final calibrated swaths are converted from v1.2 to v1.4 using GeoCue software. The withheld and overlap bits are set and all headers, appropriate point data records, and variable length records, including spatial reference information, are updated in GeoCue software and then verified using proprietary Dewberry tools. Airborne Global Positioning System Data Inertial Measurement Unit 201504 Calibrated LiDAR Point Cloud LAS 1.4 format Leading Edge Geomatics mailing and physical address

2384 Route 102 Highway

Lincoln NB E3B 7G1 Canada 506-446-4403 506-446-4402 Monday to Friday, 8 - 5 Vector Point 32078677191 Lambert Conformal Conic (State Plane Virginia South FIPS 4502) 36.766 37.966 -78.5 36.333 11482916.666 3280833.333 coordinate pair 0.000100 0.000100 U.S. survey feet North American Datum of 1983(2011) Geodetic Reference System 80 6378137.000000 298.257222 North American Vertical Datum of 1988 (Geoid 12A) 0.000100 U.S. survey feet Explicit elevation coordinate included with horizontal coordinates LiDAR points in LAS 1.4 format none U.S. Geological Survey Program Manager mailing and physical address

1400 Independence Road

Rolla MO 65401 USA (573) 308-3810 pemmett@usgs.gov Downloadable Data This data was produced for the U.S. Geological Survey according to specific project requirements. This information is provided "as is". Further documentation of this data can be obtained by contacting: USGS, 1400 Independence Road, Rolla, MO 65401. Telephone (573) 308-3810. 201601 U.S. Geological Survey Pat Emmett Program Manager mailing and physical address

1400 Independence Road

Rolla MO 65401 USA (573) 308-3810 pemmett@usgs.gov FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998 local time http://www.esri.com/metadata/esriprof80.html ESRI Metadata Profile