U.S. Geological Survey
2012
EAARL Coastal Topography--North Shore, Lake Pontchartrain, Louisiana, 2010
first
remote-sensing image
U.S. Geological Survey Data Series
674
St. Petersburg, FL
U.S. Geological Survey
This shapefile was produced from the extent of remotely sensed, geographically referenced elevation measurements by the U.S. Geological Survey (USGS). These elevation measurements were collected over the area on February 28, March 1, and March 5, 2010 using the 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, resulting in a laser swath of approximately 240 meters with an average point spacing of 2-3 meters. The EAARL, developed originally by the National Aeronautics and Space Administration (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. When resultant 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 highly detailed and accurate digital elevation maps of a portion of the north shore of Lake Pontchartrain, Louisiana, 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 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 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 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 (using the GEOID09 model). Each file contains data located in a 2-kilometer by 2-kilometer tile, where the upper-left bound can be ascertained quickly through the filename. 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 (for example, ct_e123_n4567_15). These 2-kilometer by 2-kilometer tile extents were used to create this shapefile.
The development of custom software for creating these data products has been supported by the U.S. Geological Survey CMGP's Decision Support for Coastal Science and Management project. Processed data products are used by the U.S. Geological Survey CMGP'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.
20100228
20100301
20100305
ground condition
None planned
-90.067819
-90.003856
30.357039
30.301552
ISO 19115 Topic Category
elevation
General
Airborne Lidar Processing System
ALPS
Digital Elevation Model
DEM
EAARL
Experimental Advanced Airborne Research Lidar
laser altimetry
lidar
Pilatus PC-6
remote sensing
topography
Global Change Master Science Directory
LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION
Global Change Master Science Directory
DOI/USGS/CMG > COASTAL AND MARINE GEOLOGY, U.S. GEOLOGICAL SURVEY, U.S. DEPARTMENT OF INTERIOR
GCMD Instrument
LIDAR > LIGHT DETECTION AND RANGING
Geographic Names Information System
North Shore
Lake Pontchartrain
Louisiana
Saint Tammany
United States
North America
General
Coastal Topography
General
2010
None
The U.S. Geological Survey requests to be acknowledged as the originator of this file in future products or derivative research.
Jamie M. Bonisteel-Cormier
U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
Lidar Analyst
mailing and physical address
600 4th Street South
St. Petersburg
FL
33701
USA
727 803-8747 (x3124)
727 803-2031
jcormier@usgs.gov
M-F, 8:00-4:00 ET
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 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.
Unclassified
Unclassified
None
Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.3.1.3000
The data were split into 2-kilometer by 2-kilometer tiles where the upper-left bound can be ascertained quickly through the filename. 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 (for example, ct_e123_n4567_15). These 2-kilometer by 2-kilometer tile extents were used to create this shapefile.
This shapefile completely encompasses the provided lidar data.
EAARL data were split into 2-kilometer by 2-kilometer tiles using ALPS, or the Airborne Lidar Processing System (20101022) and these extents were exported to an .xyz file (20110728).
20101022 through 20110728
Xan Fredericks
Jacobs Technology, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
Geographer/Lidar Analyst/Metadata Specialist
mailing and physical address
600 4th Street South
St. Petersburg
FL
33701
USA
727 803-8747 (x3086)
afredericks@usgs.gov
M-F, 8:00-4:00 ET
The shapefile was created from the .xyz file using Global Mapper 12 by exporting vector areas to shapefile format.
Global Mapper 12
20110803
Xan Fredericks
Jacobs Technology, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
Geographer/Lidar Analyst/Metadata Specialist
mailing and physical address
600 4th Street South
St. Petersburg
FL
33712
USA
727 803-8747 (x3086)
afredericks@usgs.gov
M-F, 8:00-4:00 ET
Vector
G-polygon
6
D_NORTH_AMERICAN_1983
Geodetic Reference System 80
6378137.000000
298.25722210100002
NRSH_tile_extents_zone15
Shapefile.
ESRI
FID
Internal feature number.
ESRI
Sequential unique whole numbers that are automatically generated.
Shape
Feature geometry.
ESRI
Coordinates defining the features.
TILE_NAME
Tile name described by UTM Zone 15 easting and northing values (in meters).
U.S. Geological Survey DSCSM
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 (for example, t_e123_n4567_15).
TILE_NUMBE
Sequential unique whole number assigned to tiles (west-to-east, north-to-south) for identification.
U.S. Geological Survey DSCSM
16
LABEL_POS
Spatial coordinates used to center display labels within tiles.
U.S. Geological Survey DSCSM
UTM Zone 15 easting and northing coordinates (in meters) used to center display labels within tiles.
The shapefile includes sequential tile number labels, tile names, and label position coordinates.
https://pubs.usgs.gov/of/2009/1078/
U.S. Geological Survey
Emily S. Klipp
Lidar Operations Manager
mailing and physical address
600 4th Street South
St. Petersburg
FL
33701
USA
727 803-8747 (x3089)
M-F, 8:30-4:30 ET
DS 674
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, or for general or scientific purposes, nor shall the act of distribution constitute 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. Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, expressed or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights.
shapefile
20110803
DVD
DVD
None
Contact U.S. Geological Survey
Vary
20100228
20100301
20100305
20120224
Xan Fredericks
Jacobs Technology, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
Geographer/Lidar Analyst/Metadata Specialist
mailing and physical address
600 4th Street South
St. Petersburg
FL
33701
USA
727 803-8747 (x3086)
afredericks@usgs.gov
M-F, 8:00-4:00 ET
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
local time
http://www.esri.com/metadata/esriprof80.html
ESRI Metadata Profile