remote-sensing image
U.S. Geological Survey2008UnknownEAARL Coastal Topography–Pearl River DeltafirstU.S. Geological Survey Data Series417Saint Petersburg, FLU.S. Geological Survey
A first surface elevation map (also known as a Digital Surface Model or DSM) of the Pearl River Delta in Louisiana and Mississippi was produced from remotely sensed, geographically referenced elevation measurements cooperatively by the U.S. Geological Survey (USGS), the National Park Service (NPS), and the National Aeronautics and Space Administration (NASA). Elevation measurements were collected over the area using the 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 50 meters per second at an elevation of approximately 300 meters. The EAARL, developed by 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 time period. When subsequent 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 a highly detailed and accurate first surface digital elevation map of the Pearl River Delta in Louisiana and Mississippi 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 (CMG) Program 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. These data are then converted to the North American Datum of 1983 and the North American Vertical Datum of 1988 (using the Geoid 03 model). Each file contains data located in a 2 km by 2 km tile, where the upper left bound can be quickly assessed through the file name. 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 CMG Program's Decision Support for Coastal Parks, Sanctuaries, and Preserves project. Processed data products are used by the U.S. Geological Survey CMG Program'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.
en
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ground condition
None planned
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Airborne Lidar Processing System
ALPShttp://remotesensing.usgs.govDigital Surface ModelDSMEAARLExperimental Advanced Airborne Research Lidarlaser altimetryLidarremote sensingtopography
http://nationalmap.govPearl River DeltaLouisianaMississippiNorthern Gulf of Mexico
http://lidar.cr.usgs.gov/First Surfacehttp://www.esri.com/news/arcuser/1104/temporal.html2008
None
The U.S. Geological Survey, National Park Service, and National Aeronautics and Space Administration request to be acknowledged as originators of this data in future products or derivative research.
mailing and physical address
600 4th Street South
Saint Petersburg
FL
33701
USA
727-803-8747 (x3026)
M-F, 8:00-5:00 EST
Amar NayegandhiJacobs Technology, U.S. Geological Survey, FISC, St. Petersburg, FLanayegandhi@usgs.gov727-803-2031Computer Scientist
Acknowledgement of the U.S. Geological Survey, Florida Integrated Science Center, as a data source would be appreciated in products developed from these data, and such acknowledgement as is standard for citation and legal practices for data source is expected by users of this data. Sharing 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.
Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.2.1350
Point Data
UnclassifiedUnclassifiedNone
The expected accuracy of the measured variables is as follows: attitude within 0.07 degree, 3 cm nominal ranging accuracy, and vertical elevation accuracy of +/-15 cm for the topographic surface. Quality checks are built into the data-processing software.
Raw elevation measurements have been determined to be within 1 meter horizontal accuracy.
Elevations are vertically consistent with the point elevation data, +/-15 cm.
The data are collected using a Cessna 310 aircraft. The NASA Experimental Advanced Airborne Research Lidar (EAARL) laser scanner collects the data using a green (532-nm) 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 and the NASA office at Wallops Flight Facility in Virginia. The navigational data are processed at Wallops Flight Facility. The navigational and raw data are then downloaded into the Airborne Lidar Processing System (ALPS). Data are converted from units of time to x,y,z points for elevation. The derived surface data can then be converted into raster data (GeoTIFFs).
Airborne Lidar Processing System
20080309 through 20080808mailing and physical address600 4th Street SouthSaint PetersburgFL33701USA727-803-8747 (x3026)M-F, 8:00-5:00 ESTComputer Scientistanayegandhi@usgs.govAmar NayegandhiJacobs Technology, U.S. Geological Survey, FISC, St. Petersburg, FL
U.S. Geological Survey2008UnknownEAARL Coastal Topography–Pearl River Deltafirstremote-sensing imageU.S. Geological Survey Data Series417Saint Petersburg, FLU.S. Geological Survey1Point elevation measurements collected by the EAARL sensor.200803092008031020080311nonenoneMetadata Specialistmailing and physical address600 4th Street SouthSaint PetersburgFL33701USA727-803-8747M-F, 8:00-5:00 ESTMetadata SpecialistU.S. Geological SurveyMetadata imported into ArcCatalog from XML file.ESRI ArcCatalog 9.2.2.135020080808
Each file contains data located in a 2 km by 2 km tile, where the upper left bound can be quickly assessed through the file name. 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).Several regions of the dataset are labeled as "No Data", which corresponds to a cell value of -32767 m in the ASPRS LAS file. These "No Data" areas are a result of the survey not covering a particular region, optical water depth of greater than 1.5 Secchi disc depths, or the manual removal of lidar processing artifacts.
Point
row and column
1.000000
1.000000
meters
Universal Transverse Mercator
North American Datum of 1983
Geodetic Reference System 80
6378137.000000
298.257222
GCS_North_American_1983
NAD_1983_UTM_Zone_
North American Vertical Datum of 1988
0.15 m
meters
Explicit elevation coordinate included with horizontal coordinates
The variables measured by EAARL are distance between aircraft and GPS satellites (m), attitude information (roll, pitch, heading in degrees), scan angle (degrees), second of the epoch (sec), and 1-ns time-resolved return intensity waveform (digital counts). Z value is referenced to orthometric elevations derived from National Geodetic Survey Geoid Model, Geoid03.
This raster represents Lidar-derived elevations.
The ASPRS LAS grid is encoded with a 1 meter resolution.
mailing and physical address
600 4th Street South
Saint Petersburg
FL
33701
USA
727-803-8747
U.S. Geological SurveyProject ManagerProject ManagerM-F, 8:00-5:00 EST
DS 417
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, nor shall the act of distribution imply 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. Reference herin to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
VaryBINARYASPRS LAS1.2DVDDVDContact U.S. Geological SurveyVary
Contact U.S. Geological Survey for details.
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20080808
mailing and physical address
Saint Petersburg
FL
33701
600 4th Street SouthUSA
727-803-8747
Metadata SpecialistU.S. Geological SurveyM-F, 8:00-5:00 ESTMetadata Specialist
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
local time
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