Originator: U.S. Geological Survey
ATM Coastal Topography--Louisiana, 2001: UTM Zone 16 (Part 2 of 2)
Geospatial_Data_Presentation_Form: remote-sensing image
Series_Name: U.S. Geological Survey Data Series
Publication_Place: St. Petersburg, FL
Publisher: U.S. Geological Survey
A first-surface elevation map was produced cooperatively from remotely sensed, geographically referenced elevation measurements by the U.S. Geological Survey (USGS) and National Aeronautics and Space Administration (NASA). Elevation measurements were collected over the area using the NASA Airborne Topographic Mapper (ATM), a scanning lidar system that measures high-resolution topography of the land surface. The ATM system is deployed on a Twin Otter or P-3 Orion aircraft and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser-ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters.
For more information on Lidar science and the Experimental Advanced Airborne Research Lidar (EAARL) system and surveys, see http://ngom.usgs.gov/dsp/overview/index.php
The purpose of this project is to produce highly detailed and accurate elevation maps of a portion of the Louisiana coastline within UTM Zone 16 for natural-resource managers and research scientists. For the corresponding Louisiana coastline data within UTM Zone 15, refer to USGS Data Series 465 (part 1 of 2).
Raw lidar data are not in a format that is generally usable by resource managers and scientists. 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 Advanced Lidar Processing System (ALPS), a multi-tiered processing system developed by a USGS-NASA collaborative project. The zero crossing of the second derivative (that is, detection of local maxima) is used to detect "first surface" topography. Statistical filtering, known as the Random Consensus Filter (RCF), is used to remove false bottom returns and other outliers from the ATM 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 converted to the North American Datum of 1983 and the North American Vertical Datum of 1988 (using the GEOID03 model). The files are in the Quarter-Quad tiling format, and the exact tile location is contained in the filename at ########_fs, where ####### is the Quarter-Quad tile ID.The development of custom software for creating these data products has been supported by the USGS CMG Program's Decision Support for Coastal Parks, Sanctuaries, and Preserves Project. Processed data products are used by the USGS 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.
Currentness_Reference: ground condition
Maintenance_and_Update_Frequency: None planned
Theme_Keyword_Thesaurus: USGS Metadata Identifier
Theme_Keyword_Thesaurus: ISO Topic Keywords 19115
Theme_Keyword: Airborne Lidar Processing System
Theme_Keyword: Digital Elevation Model
Theme_Keyword: Airborne Topographic Mapper
Theme_Keyword: laser altimetry
Theme_Keyword: remote sensing
Theme_Keyword_Thesaurus: Data Categories for Marine Planning
Theme_Keyword: bathymetry and elevation
Theme_Keyword_Thesaurus: Marine Realms Information Bank (MRIB) Keywords
Theme_Keyword: topographic mapping
Theme_Keyword_Thesaurus: USGS Thesaurus
Theme_Keyword: digital elevation models
Place_Keyword: UTM Zone 16
Place_Keyword: Gulf of Mexico
The U.S. Geological Survey and National Aeronautics and Space Administration request to be acknowledged as originators of the dataset in future products or derivative research.
Contact_Person: Xan Yates
Contact_Position: GIS/Image Analyst/Metadata Specialist
Contact_Organization: Jacobs Technology, U.S. Geological Survey, FISC
Address_Type: mailing and physical address
Contact_Voice_Telephone: 727-803-8747 (x3086)
Hours_of_Service: M-F, 9:00-5:30 EST
Address: 600 4th Street South
City: St. Petersburg
Acknowledgment 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 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.
Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcMap 126.96.36.1990
Originator: Nayegandhi, Amar, Brock, J.C., Wright, C.W.
Small footprint, waveform-resolving lidar estimation of submerged and subcanopy topography in coastal environments
Series_Name: International Journal of Remote Sensing
Issue_Identification: 30(4), p. 861-878