Originator: U.S. Geological Survey
Topographic Lidar Survey of Dauphin Island, Alabama and Chandeleur, Stake, Grand Gosier and Breton Islands, Louisiana, July 12-14, 2013 -- Classified Point Data
Geospatial_Data_Presentation_Form: binary point cloud
Series_Name: U.S. Geological Survey Data Series
Publication_Place: St. Petersburg, Fla.
Publisher: U.S. Geological Survey
A topographic lidar survey was conducted July 12-14, 2013 over Dauphin Island, Alabama and Chandeleur, Stake, Grand Gosier and Breton Islands, Louisiana.
Lidar data exchange format (LAS) 1.2 formatted classified point data files were generated based on these data.
Photo Science, Inc. was contracted by the U.S. Geological Survey (USGS) to collect and process the lidar data.
The lidar data were collected at a nominal pulse spacing (NPS) of 1.0 meter (m).
The horizontal projection and datum of the data are Universe Transverse Mercator, zone 16N, North American Datum 1983 (UTM Zone 16N NAD83), meters. The vertical datum is North American Vertical Datum 1988, Geoid 2012a (NAVD88, GEOID12A), meters.
Eighty-five LAS files, based on a 2-kilometer by 2-kilometer tiling scheme, cover the entire survey area.
These lidar data are available to Federal, State and local governments, emergency-response officials, resource managers, and the general public.
Lidar_Specification USGS-NGP Base Lidar Specification v1.0
Lidar_Sensor Leica ALS 70
Lidar_Geoid National Geodetic Survey (NGS) Geoid03
Lidar_LAS_Witheld_Point_Identifier Withheld (ignore) points were identified in these files using the standard LAS Withheld bit.
Lidar_LAS_Overage_Point_Identifier Swath "overage" points were identified in these files by adding 16 to the standard classification values.
Lidar_LAS_Class_Description Processed, but unclassified
Lidar_LAS_Class_Description Bare earth ground
Lidar_LAS_Class_Description Ignored ground
Lidar_LAS_Class_Description Overlap default (unclassified)
Lidar_LAS_Class_Description Overlap bare-earth ground
This lidar survey was acquired to document the short- and long-term changes of several different barrier island systems. Specifically, this survey supports detailed studies of Chandeleur and Dauphin Islands that resolve annual changes in beaches, berms and dunes associated with processes driven by storms, sea-level rise, and even human restoration activities.
Lidar data acquisition, calibration, and follow-on processing were completed by Photo Science, Inc. Photo Science was contracted by the U.S. Geological Survey to conduct the work.
The geographic extent of each tile falls on even 2000 x and y UTM Zone 16N NAD83 meters.
The tile names are assigned according to the U.S. National Grid (USNG) spatial address (http://www.fgdc.gov/usng/how-to-read-usng/index_html)
The last 6 digits of the file name are based on the lower-left (LL) xy coordinate of the tile.
For example, tile name 16RCU324308 uses 324 to represent an LL x-coordinate of 324,000, and uses 308 to represent an LL y-coordinate of 3,308,000 (ignoring the first digit).
Currentness_Reference: ground condition
Maintenance_and_Update_Frequency: None planned
Access_Constraints: No restrictions apply to these data.
Theme_Keyword_Thesaurus: USGS Metadata Identifier
Theme_Keyword: remote sensing
Theme_Keyword: elevation data
Theme_Keyword: laser altimetry
Theme_Keyword: bare earth
Theme_Keyword_Thesaurus: Global Change Master Science Directory (GCMD)
Theme_Keyword: LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION
Theme_Keyword: OCEAN > COASTAL PROCESSES > BARRIER ISLANDS
Theme_Keyword: COASTAL PROCESSES > BEACHES
DOI/USGS/CMG > COASTAL AND MARINE GEOLOGY, U.S. GEOLOGICAL SURVEY, U.S. DEPARTMENT OF INTERIOR
Theme_Keyword_Thesaurus: GCMD Instrument
Theme_Keyword: LIDAR > LIGHT DETECTION AND RANGING
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: Gulf of Mexico
Place_Keyword: Barrier Islands
Place_Keyword: Gulf of Mexico Barrier Islands
Place_Keyword: Stake Island
Place_Keyword: Grand Gosier Island
Place_Keyword: Breton Island
Place_Keyword: Chandeleur Islands
Place_Keyword: Dauphin Island
Place_Keyword: United States
None. However, users should be aware that temporal changes may have occurred since this dataset was collected and some parts of these data may no longer represent surface conditions. Users should not use these data for critical applications without a full awareness of its limitations. Acknowledgement of the U.S. Geological Survey would be appreciated for products derived from these data.
Contact_Organization: U.S. Geological Survey
Contact_Person: Nathaniel Plant
Address_Type: mailing and physical
Hours_of_Service: Monday through Friday 9:00 AM to 5:00 PM (Eastern Time)
Address: 600 4th St. S.
City: St. Petersburg
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. 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.
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