U.S. Geological Survey
2014
EAARL-B Submerged Topography—Barnegat Bay, New Jersey, pre-Hurricane Sandy, 2012 (.tif file)
first
raster digital data
U.S. Geological Survey Data Series
885
St. Petersburg, FL
U.S. Geological Survey
https://dx.doi.org/10.3133/ds885
A digital elevation model for part of Barnegat Bay, New Jersey, pre-Hurricane Sandy (October 2012 hurricane), was produced from remotely sensed, geographically referenced elevation measurements by the U.S. Geological Survey. Elevation measurements were collected over the area using the second-generation Experimental Advanced Airborne Research Lidar, 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 55 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 0.5-1.6 meters. The nominal vertical elevation accuracy expressed as the root mean square error (RMSE) is 20 centimeters. A peak sampling rate of 15-30 kilohertz results in an extremely dense spatial elevation dataset. More than 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.
The purpose of this project was to produce highly detailed and accurate digital elevation maps for part of Barnegat Bay, New Jersey, pre-Hurricane Sandy (October 2012 hurricane), 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 natural-resource managers and research 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 multitiered 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-B 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 although 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, whereas the trailing edge algorithm (that is, the algorithm searches for the location before 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 part 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-B 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 GEOID12A model). Each file contains data located in a 10-kilometer by 10-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 east bounding coordinate (e###000) in meters, the next 4 numbers represent the top-most UTM north bounding coordinate (n####000) in meters, and the last 2 numbers (##) represent the UTM zone in which the tile is located (for example, pre_e123_n4567_18).
The development of custom software for creating these data products has been supported by the U.S. Geological Survey CMGP's Lidar for Science and Resource 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.
20121018
20121022
20121023
20121026
ground condition
None planned
ISO 19115 Topic Category
elevation
General
Airborne Lidar Processing System
ALPS
Cessna 310
Digital Elevation Model
DEM
EAARL-B
Experimental Advanced Airborne Research Lidar
laser altimetry
lidar
remote sensing
topography
Global Change Master Science Directory
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
GCMD Instrument
LIDAR > LIGHT DETECTION AND RANGING
Geographic Names Information System
Ocean
Barnegat Bay
New Jersey
Atlantic Ocean
General
Submerged
General
2012
Pre-Hurricane Sandy
None
The U.S. Geological Survey requests to be acknowledged as originators of these data in future products or derivative research.
Xan Fredericks
Cherokee Nation Technology Solutions, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
Lidar Validation and Processing Analyst
mailing and physical address
600 4th Street South
St. Petersburg
FL
33701
USA
727 502-8086
727 502-8182
afredericks@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 periods may be inaccurate because of 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 2; Esri ArcCatalog 10.1.1.3143
5.7000 E+5
5.8000 E+5
4.41000 E+6
4.40000 E+6
-74.1829530180392
-74.0650267641200
39.8371240843687
39.7461518323065
Nayegandhi, A., Brock, J.C., and Wright, C.W.
2009
Small footprint, waveform-resolving lidar estimation of submerged and subcanopy topography in coastal environments
International Journal of Remote Sensing
v. 30, no. 4, p. 861-878
The expected accuracy of the measured variables is as follows: attitude within 0.05 degree, 3 centimeters nominal ranging accuracy, and vertical elevation accuracy of 20 centimeters RMSE for the topographic surface. Quality checks are built into the data-processing software.
Each file contains data located in a 10-kilometer by 10-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 east bounding coordinate (e###000) in meters, the next 4 numbers represent the top-most UTM north bounding coordinate (n####000) in meters, and the last 2 numbers (##) represent the UTM zone in which the tile is located (for example, pre_e123_n4567_18).
Several regions of the raster dataset are labeled as "No Data," which corresponds with a cell value of -32767 in the GeoTIFF 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. The presence of "No Data" values does not necessarily indicate an absence of land, but rather an absence of survey coverage or the presence of prolific vegetation that the laser is not able to penetrate to return bare-earth data.
Raw elevation measurements have been determined to be within 1 meter in horizontal accuracy.
Typical vertical elevation accuracies for these data are consistent with the point elevation data; however, a ground-control survey is not completed simultaneously with every lidar survey. Vertical accuracies may differ based on the type of terrain and the accuracy of the GPS and aircraft-attitude measurements.
The data were collected using a Cessna 310 aircraft. The EAARL-B laser scanner collects the data using a green-wavelength (532-nanometer) 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. The navigational data are processed and then, along with the raw data, are downloaded into ALPS, or the Airborne Lidar Processing System (20130318 - 20140106). Data are converted from units of time to x,y,z points for elevation and formatted into .las and .xyz files, and the derived surface data are converted into raster data (GeoTIFFs).
20121018 through 20140106
Xan Fredericks
Cherokee Nation Technology Solutions, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
Lidar Validation and Processing Analyst
mailing and physical address
600 4th Street South
St. Petersburg
FL
33701
USA
727 502-8086
afredericks@usgs.gov
M-F, 8:00-4:00 ET
A bias correction of -16 centimeters (value determined from instrument calibrations) was applied to the point-cloud data using ALPS (20140822) to account for a change in configuration parameters. Data are formatted into .las and .xyz files, and the derived surface data are converted into raster data (GeoTIFFs).
20140822
Christine Kranenburg
Cherokee Nation Technology Solutions, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
Programmer/Analyst
mailing and physical address
600 4th Street South
St. Petersburg
FL
33701
USA
727 502-8129
M-F, 7:30-3:30 ET
ckranenburg@usgs.gov
Metadata imported into ArcCatalog 10.1.1.3143 from XML file.
20140127
Xan Fredericks
Cherokee Nation Technology Solutions, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
Lidar Validation and Processing Analyst
mailing and physical address
600 4th Street South
St. Petersburg
FL
33701
USA
727 502-8086
M-F, 8:00-4:00 ET
afredericks@usgs.gov
Tiling Index
Raster
Pixel
row and column
2.500000
2.500000
meters
Universal Transverse Mercator
18
0.999600
-75.000000
0.000000
500000.000000
0.000000
North American Datum of 1983
Geodetic Reference System 80
6378137.000000
298.25722210100002
North American Vertical Datum of 1988
0.20
meters
Explicit elevation coordinate included with horizontal coordinates
The input parameters for the random consensus filter (RCF) were: grid cell size (buffer) = 1500 centimeters x 1500 centimeters; vertical tolerance (vertical width) = 40 centimeters.
https://pubs.usgs.gov/of/2009/1078/
U.S. Geological Survey
Xan Fredericks
Lidar Validation and Processing Analyst
mailing and physical address
600 4th Street South
St. Petersburg
FL
33701
USA
727 502-8086
M-F, 8:00-4:00 ET
DS 885
Although these data have been processed successfully on a computer system at the U.S. Geological Survey (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 describe 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.
GeoTIFF
GeoTIFF
2
https://dx.doi.org/10.3133/ds885
None
Contact U.S. Geological Survey.
Vary
Contact U.S. Geological Survey for details.
20121018
20121022
20121023
20121026
20140127
Xan Fredericks
Cherokee Nation Technology Solutions, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
Lidar Validation and Processing Analyst
mailing and physical address
600 4th Street South
St. Petersburg
FL
33701
USA
727 502-8086
M-F, 8:00-4:00 ET
afredericks@usgs.gov
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
local time
http://www.esri.com/metadata/esriprof80.html
Esri Metadata Profile