EAARL Coastal Topography--Assateague Island National Seashore, Maryland and Virginia, 2002: Bare Earth

Dataset Identification:

Resource Abstract:
ASCII XYZ point cloud data were produced from remotely sensed, geographically referenced elevation measurements acquired cooperatively by the U.S. Geological Survey (USGS) and the National Park Service (NPS). Elevation measurements were collected over Assateague Island National Seashore using the first-generation National Aeronautics and Space Administration (NASA) 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 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 60 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 NASA at Wallops Flight Facility in Virginia, measures ground elevation with a vertical resolution of 3 centimeters. A sampling rate of 3 kilohertz or higher results in an extremely dense spatial elevation dataset. Over 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.
Citation
Title EAARL Coastal Topography--Assateague Island National Seashore, Maryland and Virginia, 2002: Bare Earth
publication  Date   2016-01-01
Edition second
presentationForm  mapDigital
Series
Name U.S. Geological Survey Data Release
Issue doi:10.5066/F7NP22J5
cited responsible party - publisher
organisation Name  U.S. Geological Survey
Contact information
Address
, St. Petersburg, FL
cited responsible party - originator
organisation Name  U.S. Geological Survey
cited responsible party -
organisation Name  
Contact information
Linkage for online resource
URL: https://doi.org/10.5066/F7NP22J5
Topic Category:  elevation
Keywords:
Theme keywords (theme):
Airborne Lidar Processing System
ALPS
EAARL
Experimental Advanced Airborne Research Lidar
laser altimetry
lidar
remote sensing
topography
USGS National Assessment Project
ASCII XYZ (Bare earth)
thesaurus name >
Title General
Theme keywords (theme):
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
thesaurus name >
Title Global Change Master Science Directory
Theme keywords (theme):
LIDAR > LIGHT DETECTION AND RANGING
thesaurus name >
Title GCMD Instrument
Theme keywords (theme):
distributions
bathymetry and elevation
thesaurus name >
Title Data Categories for Marine Planning
Theme keywords (theme):
altimetry
topographic mapping
thesaurus name >
Title Marine Realms Information Bank (MRIB) Keywords
Theme keywords (theme):
LIDAR
topography
digital elevation models
thesaurus name >
Title USGS Thesaurus
Location keywords:
Maryland
Virginia
Assateague Island
Atlantic Ocean
thesaurus name >
Title Geographic Names Information System
Stratum keywords:
Bare earth
thesaurus name >
Title General
Temporal keywords:
2002
thesaurus name >
Title General
purpose:
The purpose of this project was to provide highly detailed and accurate elevation data of the Assateague Island National Seashore in 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 St. Petersburg Coastal and Marine Science Center (SPCMSC) data management protocols were followed, this survey was assigned a USGS field activity number (FAN), 02LTS09. Additional survey and data details are available at http://cmgds.marine.usgs.gov/fan_info.php?fan=02LTS09.
Resource language:  eng; USA
Resource progress code:  completed
Resource Maintenance Information
maintenance or update frequency:  notPlanned
Constraints on resource usage:
Constraints
Use limitation statement:
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.
Constraints on resource usage:
Legal Constraints
use constraint:  otherRestrictions
Other constraints
Use Constraints: The U.S. Geological Survey requests to be acknowledged as originator of these data in future products or derivative research.
Constraints on resource usage:
Legal Constraints
Access Constraints  otherRestrictions
Other constraints
Access Constraints: None
Constraints on resource usage:
Security Constraints
Classification  unclassified
Classification System Unclassified
Handling Description None
Spatial representation type code:  vector
Processing environment:  Native Dataset Environment: Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.3.1.4959
Resource extent
Geographic Extent
Geographic Bounding Box
westBoundLongitude  -75.38897738
eastBoundLongitude  -75.09094815
northBoundLatitude  38.32564756
southBoundLatitude  37.85682683
Temporal Extent
Additional information on resource:
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 USGS'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 originally 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 "first returns" are indicative of vegetation-canopy height, or bare ground in the absence of vegetation, whereas "last returns" typically represent "bare-earth" elevations under vegetation. The terms first surface and bare earth refer to the digital elevation data of the terrain, but while 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, 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 (Geoid 99). The development of custom software for creating these data products has been supported by the USGS CMGP's Lidar for Science and Resource Management project. Processed data products are used by the 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.
Credits:
Acknowledgment of the USGS 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 USGS 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.
point of contact - pointOfContact
individual Name Christine Kranenburg
organisation Name  Cherokee Nation Technologies, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
position Name Computer Scientist
Contact information
Telephone
Voice 727 502-8129
Fax 727 502-8182
Address
600 4th Street South, St. Petersburg, FL, 33701 Country USA
electronic Mail Address ckranenburg@usgs.gov
hoursOfService M-F, 8:00-4:00 ET
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Content information: feature catalog description

Included With Dataset  false
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Scope of quality information
scope level  dataset
Resource lineage description
AbsoluteExternalPositionalAccuracy
name Of Measure Horizontal Positional Accuracy Report
evaluation Method Description  Raw elevation measurements have been determined to be within 1 meter in horizontal accuracy.
AbsoluteExternalPositionalAccuracy
name Of Measure Vertical Positional Accuracy Report
evaluation Method Description  Point elevation measurements have been determined to be within +/- 15 cm in vertical accuracy.
Completeness Commission
evaluation Method Description  These point-cloud data may appear sparse or nonexistent, which is a result of automated filtering, manual removal of artifacts or lack of survey coverage.
Completeness Omission
evaluation Method Description  These point-cloud data may appear sparse or nonexistent, which is a result of automated filtering, manual removal of artifacts or lack of survey coverage.
ConceptualConsistency
measure Description  These data were processed for topography ONLY.

Resource distribution information

Distributor
distributor contact - distributor
individual Name Christine Kranenburg
organisation Name  Cherokee Nation Technologies, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
position Name Computer Scientist
Contact information
Telephone
Voice 727-502-8129
Address
600 4th Street South, St. Petersburg, FL, 33701 Country USA
electronic Mail Address ckranenburg@usgs.gov
Standard ordering process
fees None, if obtained online.
Format
Format name ASCII
Format version 1
specification > XYZ
Digital Transfer Options
Linkage for online resource
name ASCII
URL: https://coastal.er.usgs.gov/data-release/doi-F7NP22J5/data/ASIS2002_EAARLA_BE_z18_n88g99.zip
link function 
Description 

Metadata data stamp:  2017-07-27
Resource Maintenance Information
maintenance or update frequency:  annually
notes: This metadata was automatically generated from the FGDC Content Standards for Digital Geospatial Metadata standard (version FGDC-STD-001-1998) using the 2012-06-20T17:21:00 version of the FGDC RSE to ISO 19115-2 transform.
Metadata contact - pointOfContact
individual Name Christine Kranenburg
organisation Name  Cherokee Nation Technologies, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
position Name Computer Scientist
Contact information
Telephone
Voice (727) 502-8129
Address
600 4th Street South, St. Petersburg, FL, 33701 Country USA
electronic Mail Address ckranenburg@usgs.gov
Metadata scope code  dataset
Metadata language  eng; USA
Metadata character set encoding:   utf8
Metadata standard for this record:  ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data
standard version:  ISO 19115-2:2009(E)
Metadata record identifier:  8fc1dcd1-2e30-4851-b251-4df9010404a8

Metadata record format is ISO19139-2 XML (MI_Metadata)