U.S. Geological Survey 20170324 first binary point cloud U.S. Geological Survey Data Release doi:10.5066/F7NP22NH St. Petersburg, FL U.S. Geological Survey https://doi.org/10.5066/F7NP22NH Binary point-cloud data were produced for Assateague Island, Maryland and Virginia, post-Hurricane Hermine, from remotely sensed, geographically referenced elevation measurements collected by Quantum Spatial using a Riegl VQ-880-G (532-nm wavelength circular scan and 1064-nm wavelength linear scan) lidar sensor. The purpose of this project was to produce a highly detailed and accurate digital elevation map for Assateague Island, Maryland and Virginia for use as a management tool and to make these data available to natural-resource managers and research scientists. To ensure that SPCMSC data management protocols were followed, this survey was assigned a USGS field activity number (FAN), 16CNT03. Additional survey and data details are available at http://cmgds.marine.usgs.gov/fan_info.php?fan=16CNT03. USGS Contract: G16PC00016 Task Order Number: G16D01063 Processed data products are used by the U.S. Geological Survey (USGS) CMGP's National Assessment of Coastal Change Hazards project to quantify the vulnerability of shorelines to coastal change hazards such as severe storms, sea-level rise, and shoreline erosion and retreat. U.S. Geological Survey National Geospatial Program lidar Base Specification, Version 1.2 Riegl VQ-880-G Unlimited 0.7 2 0.7 2 500 120 40 160 245 1.3 35 532 0 0.7 364 50 National Geodetic Survey (NGS) Geoid12B 19.6 0.072 13 1.4 6 Withheld (ignore) 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 1 Processed, but Unclassified 2 Bare earth ground 7 Low Noise 17 Bridge Decks 40 Bathymetric Bottom 41 Water Surface 45 Water Column 20160910 20160912 ground condition Complete None planned USGS Metadata Identifier USGS:86f6d7f7-0ab5-4779-b611-d1d293d1b775 ISO 19115 Topic Category elevation None Digital Elevation Model DEM extratropical cyclone laser altimetry lidar Cessna Caravan remote sensing shoreline submerged topography topography Global Change Master Science Directory LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION OCEAN > COASTAL PROCESSES > BARRIER ISLANDS OCEAN > COASTAL PROCESSES > BEACHES OCEAN > COASTAL PROCESSES > SHORELINE DISPLACEMENT DOI/USGS/CMG > COASTAL AND MARINE GEOLOGY, U.S. GEOLOGICAL SURVEY, U.S. DEPARTMENT OF INTERIOR GCMD Instrument lidar > LIGHT DETECTION AND RANGING Geographic Names Information System Assateague Island Maryland Virginia Delmarva Peninsula United States None Bare Earth Submerged None 2016 Post-Hurricane Hermine None Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. The U.S. Geological Survey requests to be acknowledged as originator of these data in future products or derivative research. Xan Fredericks U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL Cartographer/Lidar Coordinator mailing and physical address

600 4th Street South

St. Petersburg FL 33701 USA 727 502-8086 727 502-8182 afredericks@usgs.gov M-F, 8:00-4:00 ET Acknowledgment of the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, as a data source would be appreciated in products developed from these data, and such acknowledgment as is standard for citation and legal practices for data source is expected. Sharing of new data layers developed directly from these data would also be appreciated by the U.S. Geological Survey staff. Users should be aware that comparisons with other datasets for the same area from other periods may be inaccurate because of inconsistencies resulting from changes in photointerpretation, mapping conventions, and digital processes over time. These data are not legal documents and are not to be used as such. Unclassified Unclassified None Microsoft Windows 7 Enterprise Service Pack 1; Esri ArcCatalog 10.2.2.3552 -75.42335013 -75.07955612 38.33510704 37.83868211 Quantum Spatial reports that data cover the entire area specified for this project, approximately 52,196.2 acres. Quantum Spatial reports that the contract specifications required that raw Non-vegetated Vertical Accuracy (NVA) be computed from the both the raw lidar point cloud swath files and the derived DEMs. Additionally, Vegetated Vertical Accuracy (VVA) was also to be computed from the derived DEMS. The NVA was tested with 13 independent check points provided to QSI by USGS 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. The VVA was tested with 12 independent check points, also provided to QSI by USGS, located in vegetated terrain and also witheld from the calibration and post processing of the lidar point cloud data. VVA points were also distributed throughout the project area as feasible. Specifications for this project require that the NVA be 19.6 meters or better AccuracyZ at 95% confidence level and that the VVA be 29.4 cm or better AccuracyZ at the 95th percentile. NVA Root Mean Square Error (RMSE) was calculated using the 13 independent check points provided by the USGS and resulted in a value of 0.072m. 0.072 meters AccuracyZ at the 95 percent Confidence Interval for Raw LAS NVA. 0.063 meters AccuracyZ at the 95 percent Confidence Interval for DEM NVA. 0.137 meters AccuracyZ at the 95th percentile for DEM VVA. 0.072 meters AccuracyZ at the 95 percent Confidence Interval for Raw LAS NVA. 0.063 meters AccuracyZ at the 95 percent Confidence Interval for DEM NVA. 0.137 meters AccuracyZ at the 95th percentile for DEM VVA. Quantum Spatial reports that the 13 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 0.037 meters resulting in an AccuracyZ at the 95% confidence level of 0.072 meters. The 13 NVA check points were also compared to the elevations of the derived bare earth DEMs. The RMSE was computed to be 0.032 meters resulting in an AccuracyZ of 0.063 meters at the 95% confidence level. NVA AccuracyZ has been tested and meets the required 19.6 meter NVA at 95% confidence level using (RMSEz * 1.9600) for both the raw lidar point cloud and derived DEMs, as defined by the National Standards for Spatial Data Accuracy (NSSDA) and herein reported using National Digital Elevation Program (NDEP)/ASPRS Guidelines. The 13 VVA check points were also surveyed using the closed level loop technique. Elevations for these points were compared to the elevations of the derived bare earth DEMs. The RMSE was computed to be 0.078 meters resulting in an AccuracyZ of 0.137 meters at the 95th percentile. AccuracyZ has been tested on the derived bare earth DEMs and meets the required 29.4 meter VVA using the 95th percentile of the absolute value of all vertical errors in all combined vegetation classes as defined by the National Standards for Spatial Data Accuracy (NSSDA); and herein reported using National Digital Elevation Program (NDEP)/ASPRS Guidelines. Quantum Spatial reports the following steps for 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 to perform manual relative accuracy calibration and filter erroneous points. Apply the refraction correction necessary for bathymetric data. Classify ground/bathymetric 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. Base_Station_Control, SBETs, SGCPs, RAW_lidar 20161130 Quantum Spatial mailing and physical

517 SW 2nd Street, Suite 400

Corvallis OR 97333 USA 541-752-1204 541-752-3770 Monday through Friday 8:30 AM to 5:00 PM (Pacific Standard Time) Quantum Spatial reports the following steps for 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 density information and verify final accuracy calculations for the project using ground control quality check points. Base_Station_Control, SBETs, QCPs, RAW_lidar 20161130 Classified_lidar Quantum Spatial mailing and physical

517 SW 2nd Street, Suite 400

Corvallis OR 97333 USA 541-752-1204 541-752-3770 Monday through Friday 8:30 AM to 5:00 PM (Pacific Standard Time) Added keywords section with USGS persistent identifier as theme keyword. 20201013 U.S. Geological Survey VeeAnn A. Cross Marine Geologist Mailing and Physical

384 Woods Hole Road

Woods Hole MA 02543-1598 508-548-8700 x2251 508-457-2310 vatnipp@usgs.gov Quantum Spatial reports that these LAS files include all data points collected. No points have been removed or excluded. Shaded relief images have been visually inspected for data errors such as pits, border artifacts, and shifting. Lidar flight lines have been examined to ensure consistent elevation values across overlapping flight lines. The raw point cloud is of good quality and data passes Vertical Accuracy specifications. Vector Point Universal Transverse Mercator 18 0.999600 -75.000000 0 500000.000000 0 coordinate pair 0.01 0.01 meters North American Datum of 1983 (2011) Geodetic Reference System 80 6378137.000000 298.25722210100002 North American Vertical Datum of 1988 (GEOID12B) 0.01 meters Explicit elevation coordinate included with horizontal coordinates U.S. Geological Survey Xan Fredericks Cartographer/Lidar Coordinator, U.S. Geological Survey mailing and physical address

600 4th Street South

St. Petersburg FL 33701 USA 727 502-8086 M-F, 8:00-4:00 ET ASIS2016_HRHM_SM_z18_n88g12B_classified.laz Although these data have been processed successfully on a computer system at the USGS, no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The USGS shall not be held liable for improper or incorrect use of the data described and/or contained herein. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Compressed LAS (LAZ) Compressed LAS (LAZ) 1.4 https://coastal.er.usgs.gov/data-release/doi-F7NP22NH/data/ASIS2016_HRHM_SM_z18_n88g12B_classified.zip None Contact U.S. Geological Survey for details. 20201102 Xan Fredericks U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL Cartographer/Lidar Coordinator mailing and physical address

600 4th Street South

St. Petersburg FL 33701 USA 727 502-8086 afredericks@usgs.gov M-F, 8:00-4:00 ET Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998 local time