U.S. Geological Survey 2011 first remote-sensing image U.S. Geological Survey Data Series 616 St. Petersburg, FL U.S. Geological Survey Binary point-cloud data were produced from remotely sensed, geographically referenced elevation measurements by the U.S. Geological Survey (USGS). Elevation measurements were collected over the area using the Experimental Advanced Airborne Research Lidar (EAARL), a pulsed laser ranging system mounted onboard an aircraft to measure ground elevation, vegetation canopy, and coastal topography. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multispectral color-infrared (CIR) camera, two precision dual frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for sub-meter georeferencing of each laser sample. The system uses high-frequency laser beams directed at the Earth's surface through an opening in the bottom of the aircraft's fuselage. The laser system records the time difference between emission of the laser beam and the reception of the reflected laser signal in the aircraft. The plane travels over the target area at approximately 50 meters per second at an elevation of approximately 300 meters, resulting in a laser swath of approximately 240 meters with an average point spacing of 2-3 meters. The EAARL, developed originally by the National Aeronautics and Space Administration (NASA) at Wallops Flight Facility in Virginia, measures ground elevation with a vertical resolution of 15 centimeters. A sampling rate of 3 kilohertz or higher results in an extremely dense spatial elevation dataset. Over 100 kilometers of coastline can be easily surveyed within a 3- to 4-hour mission. When resultant elevation maps for an area are analyzed, they provide a useful tool to make management decisions regarding land development. The purpose of this project was to produce highly detailed and accurate digital elevation maps of a portion of the northern Outer Banks coastline beachface in North Carolina, post-Nor'Ida (November 2009 nor'easter), for use as a management tool and to make these data available to natural-resource managers and research scientists. Raw lidar data are not in a format that is generally usable by resource managers and scientists for scientific analysis. Converting dense lidar elevation data into a readily usable format without loss of essential information requires specialized processing. The U.S. Geological Survey's Coastal and Marine Geology Program (CMGP) has developed custom software to convert raw lidar data into a GIS-compatible map product to be provided to GIS specialists, managers, and scientists. The primary tool used in the conversion process is Airborne Lidar Processing System (ALPS), a multi-tiered processing system developed by a USGS-NASA collaborative project. Specialized processing algorithms are used to convert raw waveform lidar data acquired by the EAARL to georeferenced spot (x,y,z) returns for "first surface" and "bare earth" topography. The terms first surface and bare earth refer to the digital elevation data of the terrain, but while first-surface data includes vegetation, buildings, and other man-made structures, bare-earth data does not. The zero crossing of the second derivative (that is, detection of stationary points) is used to detect the first return, resulting in "first surface" topography, while the trailing edge algorithm (that is, the algorithm searches for the location prior to the last return where direction changes along the trailing edge) is used to detect the range to the last return or "bare earth" (the first and last returns being the first and last significant measurable portion of the return pulse). Statistical filtering, known as the Random Consensus Filter (RCF), is used to remove false bottom returns and other outliers from the EAARL topography data. The filter uses a grid of non-overlapping square cells (buffer) of user-defined size overlaid onto the original point cloud. The user also defines the vertical tolerance (vertical width) based on the topographic complexity and point sampling density of the data. The maximum allowable elevation range within a cell is established by this vertical tolerance. An iterative process searches for the maximum concentration of points within the vertical tolerance, and removes those points outside of the tolerance (Nayegandhi and others, 2009). These data are then converted to the North American Datum of 1983 and the North American Vertical Datum of 1988 (using the GEOID09 model). Each file contains data located in a 2-kilometer by 2-kilometer tile, where the upper-left bound can be assessed quickly through the filename. The first 3 numbers in the filename represent the left-most UTM easting coordinate (e###000) in meters, the next 4 numbers represent the top-most UTM northing coordinate (n####000) in meters, and the last 2 numbers (##) represent the UTM zone in which the tile is located (ex. fs_e123_n4567_18). The development of custom software for creating these data products has been supported by the U.S. Geological Survey CMGP's Decision Support for Coastal Science and Management project. Processed data products are used by the U.S. Geological Survey CMGP's National Assessments 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. 20091127 20091129 ground condition Complete None planned ISO 19115 Topic Category elevation General Airborne Lidar Processing System ALPS Digital Elevation Model DEM EAARL Experimental Advanced Airborne Research Lidar laser altimetry lidar Pilatus PC-6 remote sensing topography General Outer Banks North Carolina United States North America General First Surface General 2009 Post-Nor'Ida None The U.S. Geological Survey requests to be acknowledged as the originator of these data in future products or derivative research. Amar Nayegandhi Jacobs Technology, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL Remote Sensing Specialist/Project Manager mailing and physical address

600 4th Street South

St. Petersburg FL 33701 USA 727 803-8747 (x3026) 727 803-2031 anayegandhi@usgs.gov M-F, 9:00-5:00 EST 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 time periods may be inaccurate due to 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 XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.2.1350 4.4200 E+5 4.4400 E+5 3.98200 E+6 3.98000 E+6 -75.6433710098229 -75.6210457467594 35.980824780945 35.9626770407786 Nayegandhi, A., Brock, J.C., and Wright, C.W. 2009 International Journal of Remote Sensing 30(4), p. 861-878 The expected accuracy of the measured variables is as follows: attitude within 0.07 degree, 3 centimeters nominal ranging accuracy, and vertical elevation accuracy of +/-15 centimeters for the topographic surface. Quality checks are built into the data-processing software. Each file contains data located in a 2-kilometer by 2-kilometer tile where the upper-left bound can be assessed quickly through the filename. The first 3 numbers in the filename represent the left-most UTM easting coordinate (e###000) in meters, the next 4 numbers represent the top-most UTM northing coordinate (n####000) in meters, and the last 2 numbers (##) represent the UTM zone in which the tile is located (for example, fs_e123_n4567_18). These point-cloud data may appear sparse or nonexistent, which is a result of removal from manual editing or lack of survey coverage. Raw elevation measurements have been determined to be within 1 meter in horizontal accuracy. Typical vertical elevation accuracies for these data are consistent with the point elevation data, +/-15 centimeters. However, a ground-control survey is not conducted simultaneously with every lidar survey. Vertical accuracies may vary based on the type of terrain and the accuracy of the GPS and aircraft-attitude measurements. The data were collected using a Pilatus PC-6 aircraft. The Experimental Advanced Airborne Research Lidar (EAARL) laser scanner collects the data using a green-wavelength (532-nanometer) raster scanning laser, while a digital camera acquires a visual record of the flight. The data are stored on hard drives and archived at the U.S. Geological Survey office in St. Petersburg, Florida. The navigational data are processed and then, along with the raw data, are downloaded into ALPS, or the Airborne Lidar Processing System (20091128 - 20101026). Data are converted from units of time to x,y,z points for elevation and formatted into .las and .xyz files. The derived surface data can then also be converted into raster data (GeoTIFFs). 20091127 through 20101026 Jamie M. Bonisteel-Cormier U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL Lidar Analyst mailing and physical address

600 4th Street South

St. Petersburg FL 33701 USA 727 803-8747 (x3124) jcormier@usgs.gov M-F, 8:00-4:00 EST Metadata imported into ArcCatalog from XML file. 20101202 Xan Fredericks Jacobs Technology, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL GIS Analyst/Metadata Specialist mailing and physical address

600 4th Street South

St. Petersburg FL 33701 USA 727 803-8747 (x3086) M-F, 8:00-4:00 EST afredericks@usgs.gov Point row and column 2.500000 2.500000 meters Universal Transverse Mercator 18 0.999600 -75.000000 0.000000 500000.000000 0.000000 North American Datum of 1983 Geodetic Reference System 80 6378137.000000 298.25722210100002 North American Vertical Datum of 1988 0.15 meters Explicit elevation coordinate included with horizontal coordinates The input parameters for the random consensus filter (RCF) were: grid cell size (buffer) = 6 meters x 6 meters; vertical tolerance (vertical width) = 500 centimeters. https://pubs.usgs.gov/of/2009/1078/ U.S. Geological Survey Amar Nayegandhi Project Manager mailing and physical address

600 4th Street South

St. Petersburg FL 33701 USA 727 803-8747 (x3026) M-F, 9:00-5:00 EST DS 616 This DVD publication was prepared by an agency of the United States Government. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, 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 U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and/or contained herein. Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. BINARY ASPRS LAS 1.2 DVD DVD Vary Contact U.S. Geological Survey. Vary Contact U.S. Geological Survey for details. 20091127 20091129 20110720 Xan Fredericks Jacobs Technology, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL GIS Analyst/Metadata Specialist mailing and physical address

600 4th Street South

St. Petersburg FL 33701 USA 727 803-8747 (x3086) M-F, 8:00-4:00 EST afredericks@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