Metadata: Identification_Information: Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 2017 Title: Lidar-Derived Bare-Earth XYZ for EAARL Coastal Topography—Cape Hatteras, North Carolina, Pre-Hurricane Isabel, 2003 Edition: first Geospatial_Data_Presentation_Form: tabular digital data Series_Information: Series_Name: U.S. Geological Survey Data Release Issue_Identification: doi:10.5066/F76W9879 Publication_Information: Publication_Place: St. Petersburg, FL Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.5066/F76W9879 Description: Abstract: ASCII XYZ data for Cape Hatteras, North Carolina, were produced from remotely sensed, geographically referenced elevation measurements collected pre-Hurricane Isabel on September 16, 2003 by the U.S. Geological Survey, in cooperation with the National Aeronautics and Space Administration (NASA). Elevation measurements were collected over the area using the first-generation Experimental Advanced Airborne Research Lidar (EAARL-A), a pulsed laser ranging system mounted onboard an aircraft to measure ground elevation, vegetation canopy, and coastal topography. 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 55 meters per second at an elevation of approximately 300 meters, resulting in a laser swath of approximately 240 meters. More than 100 kilometers of coastline can be surveyed easily 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. Purpose: The purpose of this project was to produce a highly detailed and accurate digital elevation map for a portion of Cape Hatteras, North Carolina, 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 retroactively assigned a USGS field activity number (FAN), 03LTS01. Additional survey and data details are available at https://cmgds.marine.usgs.gov/fan_info.php?fan=03LTS01. Supplemental_Information: Raw lidar data are not in a format that is generally usable by natural-resource managers and research 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 multitiered processing system developed originally by a USGS-NASA collaborative project. Specialized processing algorithms are used to convert raw waveform lidar data acquired by the EAARL-A 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, although first-surface data include vegetation, buildings, and other manmade structures, bare-earth data do 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, whereas the trailing edge algorithm (that is, the algorithm searches for the location before 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 part 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-A 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 GEOID96 model); please note that these data are not suitable for determining absolute elevation measurements. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 20030916 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -75.75078270 East_Bounding_Coordinate: -75.50819490 North_Bounding_Coordinate: 35.31414370 South_Bounding_Coordinate: 35.18720550 Keywords: Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:c3ee3b1d-1c3d-4dc5-a9d0-cb82d38ed7f4 Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: elevation Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: lidar Theme_Keyword: remote sensing Theme_Keyword: topography Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: Airborne Lidar Processing System Theme_Keyword: ALPS Theme_Keyword: Cessna 310 Theme_Keyword: EAARL Theme_Keyword: Experimental Advanced Airborne Research Lidar Theme_Keyword: laser altimetry Theme_Keyword: point cloud data Theme: Theme_Keyword_Thesaurus: Global Change Master Science Directory Theme_Keyword: OCEAN > BATHYMETRY/SEAFLOOR TOPOGRAPHY > SEAFLOOR TOPOGRAPHY Theme_Keyword: OCEAN > COASTAL PROCESSES > COASTAL ELEVATION Theme_Keyword: DOI/USGS/CMG > COASTAL AND MARINE GEOLOGY, U.S. GEOLOGICAL SURVEY, U.S. DEPARTMENT OF INTERIOR Theme: Theme_Keyword_Thesaurus: GCMD Instrument Theme_Keyword: LIDAR > LIGHT DETECTION AND RANGING Place: Place_Keyword_Thesaurus: Geographic Names Information System Place_Keyword: Cape Hatteras Place_Keyword: North Carolina Stratum: Stratum_Keyword_Thesaurus: None Stratum_Keyword: Bare Earth Temporal: Temporal_Keyword_Thesaurus: None Temporal_Keyword: 2003 Access_Constraints: None Use_Constraints: 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. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Xan Fredericks Contact_Organization: U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL Contact_Position: Cartographer/Lidar Coordinator Contact_Address: Address_Type: mailing and physical address Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: 727 502-8086 Contact_Facsimile_Telephone: 727 502-8182 Contact_Electronic_Mail_Address: afredericks@usgs.gov Hours_of_Service: M-F, 8:00-4:00 ET Data_Set_Credit: 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. Security_Information: Security_Classification_System: Unclassified Security_Classification: Unclassified Security_Handling_Description: None Native_Data_Set_Environment: Microsoft Windows 7 Enterprise Service Pack 1; Esri ArcCatalog 10.2.2 Cross_Reference: Citation_Information: Originator: Nayegandhi, A., Brock, J.C., and Wright, C.W. Publication_Date: 2009 Title: Small footprint, waveform-resolving lidar estimation of submerged and subcanopy topography in coastal environments Series_Information: Series_Name: International Journal of Remote Sensing Issue_Identification: v. 30 no. 4, p. 861-878 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The expected accuracy of the measured variables are as follows: attitude within 0.07 degree, 3-cm nominal ranging accuracy, and vertical elevation accuracy of +/-30 cm for the topographic surface. Quality checks are built into the data-processing software. Logical_Consistency_Report: These data are located in UTM Zone 18. Completeness_Report: These point-cloud data may appear sparse or nonexistent in some areas, which may be a result of manual removal during the editing process, or from lack of survey coverage. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Raw lidar measurements have been determined to be within 1 meter in horizontal accuracy. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: Typical vertical elevation accuracies for these data are consistent with the point elevation data, +/-30 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. Lineage: Process_Step: Process_Description: The data are collected using a Cessna 310 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 (20110812 - 20111011). Data are converted from units of time to x,y,z points for elevation and formatted into .xyz files, with quality checks built into the software. Synchronously (or nearly synchronously) with the post-Hurricane Isabel (20030921) airborne mission, a Coastal Research Amphibious Buggy (CRAB), a rolling 35-foot tripod survey station features instrumentation to survey transects from the dry beach out to approximately 25 feet of water, was conducted. This instrument was used to measure elevations along the beach and shallow water areas. The expected root mean square error (rmse) accuracy of these ground data was approximately 10 cm. Based on comparison to data collected for this mission, the mean offset between the ground-based surveys and bare earth lidar was 27 cm (lidar elevations higher than the ground-based measurements) and the rmse between the two measurements was 1.94 m. The data are then datum converted to the North American Vertical Datum of 1988 using GEOID96. Process_Date: 20111011 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Xan Fredericks Contact_Organization: U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL Contact_Position: Cartographer/Lidar Coordinator Contact_Address: Address_Type: mailing and physical address Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: 727 502-8086 Contact_Electronic_Mail_Address: afredericks@usgs.gov Hours_of_Service: M-F, 8:00-4:00 ET Process_Step: Process_Description: Metadata imported into ArcCatalog 10.2.2 from XML file. Process_Date: 20161013 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Xan Fredericks Contact_Organization: U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL Contact_Position: Cartographer/Lidar Coordinator Contact_Address: Address_Type: mailing and physical address Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: 727 502-8086 Contact_Electronic_Mail_Address: afredericks@usgs.gov Hours_of_Service: M-F, 8:00-4:00 ET Process_Step: Process_Description: Keywords section of metadata optimized by adding USGS theme keywords. Process_Date: 20180524 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Arnell S. Forde Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical address Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Contact_Voice_Telephone: 727-502-8000 Contact_Electronic_Mail_Address: aforde@usgs.gov Process_Step: Process_Description: Added keywords section with USGS persistent identifier as theme keyword. Process_Date: 20201013 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: VeeAnn A. Cross Contact_Position: Marine Geologist Contact_Address: Address_Type: Mailing and Physical Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: 508-548-8700 x2251 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: vatnipp@usgs.gov Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Point Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 1e-07 Longitude_Resolution: 1e-07 Geographic_Coordinate_Units: Decimal degrees Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1983 Ellipsoid_Name: Geodetic Reference System 80 Semi-major_Axis: 6378137.000000 Denominator_of_Flattening_Ratio: 298.25722210100002 Vertical_Coordinate_System_Definition: Altitude_System_Definition: Altitude_Datum_Name: North American Vertical Datum of 1988 (GEOID96) Altitude_Resolution: 0.20 Altitude_Distance_Units: meters Altitude_Encoding_Method: Explicit elevation coordinate included with horizontal coordinates Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: The input parameters for the random consensus filter (RCF) were: grid cell size (buffer) = 800 centimeters x 800 centimeters; vertical tolerance (vertical width) = 1000 centimeters for bare-earth topography. Entity_and_Attribute_Detail_Citation: https://pubs.usgs.gov/of/2009/1078/ Detailed_Description: Entity_Type: Entity_Type_Label: CAHA2003_PreIsabel_EAARLA_BE_n88g96.xyz Entity_Type_Definition: This file contains location and elevation data (.xyz), which is provided in ASCII space-delimited format. Entity_Type_Definition_Source: Internally devised to maintain naming consistency. Attribute: Attribute_Label: X Attribute_Definition: Longitude in decimal degrees Attribute_Definition_Source: North American Datum of 1983 Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -75.75078270 Range_Domain_Maximum: -75.50819490 Attribute: Attribute_Label: Y Attribute_Definition: Latitude in decimal degrees Attribute_Definition_Source: North American Datum of 1983 Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 35.18720550 Range_Domain_Maximum: 35.31414370 Attribute: Attribute_Label: Z Attribute_Definition: Altitude in meters Attribute_Definition_Source: North American Vertical Datum of 1988 (GEOID96) Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -1.61 Range_Domain_Maximum: 11.92 Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Xan Fredericks Contact_Position: Cartographer/Lidar Coordinator Contact_Address: Address_Type: mailing and physical address Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: 727 502-8086 Hours_of_Service: M-F, 8:00-4:00 ET Resource_Description: CAHA2003_PreIsabel_EAARLA_BE_n88g96.xyz Distribution_Liability: Although these data have been processed successfully on a computer system at the U.S. Geological Survey (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 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. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: ASCII Format_Specification: XYZ Format_Version_Number: 1 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://coastal.er.usgs.gov/data-release/doi-F76W9879/data/CAHA2003_PreIsabel_EAARLA_BE_n88g96.zip Fees: None Ordering_Instructions: Contact U.S. Geological Survey. Turnaround: Vary Custom_Order_Process: Contact U.S. Geological Survey for details. Metadata_Reference_Information: Metadata_Date: 20201102 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Xan Fredericks Contact_Organization: U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL Contact_Position: Cartographer/Lidar Coordinator Contact_Address: Address_Type: mailing and physical address Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: 727 502-8086 Contact_Electronic_Mail_Address: afredericks@usgs.gov Hours_of_Service: M-F, 8:00-4:00 ET Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time