U.S. Geological Survey
2014
1-Meter Sample Resolution Interferometric Swath Backscatter Data Collected in 2012 from the Chandeleur Islands, Louisiana (U.S. Geological Survey Field Activity Number 12BIM03)
Raster
https://pubs.usgs.gov/ds/0847/data/raster/12BIM03_IFS_Mosaic.zip
Nancy T. DeWitt
Julie C. Bernier
William R. Pfeiffer
Jennifer L. Miselis
James G. Flocks
B.J. Reynolds
Dana S. Wiese
Kyle W. Kelso
2014
Coastal Bathymetry Data Collected in 2012 from the Chandeleur Islands, Louisiana
multimedia presentation
U.S. Geological Survey Data Series
847
St. Petersburg, Florida
U.S. Geological Survey
https://doi.org/10.3133/ds847
As part of the Barrier Island Evolution Research Project, scientists from the U.S. Geological Survey's St. Petersburg Coastal and Marine Science Center conducted nearshore geophysical surveys off the northern Chandeleur Islands, Louisiana, in June of 2012. The overall objective of the study is to better understand barrier-island geomorphic evolution, particularly storm-related depositional and erosional processes that shape the islands over annual to interannual timescales (1-5 years). The collection of geophysical data will allow us to identify relationships between the geologic history of the island and its present day morphology and sediment distribution. This mapping effort was the first in a series of three planned surveys in this area. High resolution geophysical data collected in each of 3 consecutive years along this rapidly changing barrier-island system will provide a unique time-series dataset that will significantly further the analyses and geomorphological interpretations of this and other coastal systems, improving our understanding of coastal response and evolution over short time scales (1-5 years). This report serves as an archive of processed interferometric swath and single-beam bathymetry data that were collected during two cruises (USGS Field Activity Numbers 12BIM03 and 12BIM04) along the northern portion of the Chandeleur Islands, Breton National Wildlife Refuge, Louisiana in July of 2012. Geographic information system data products include a 50 m-cell-size interpolated bathymetry grid surface, trackline maps, and point data files. Additional files include error analysis maps, Field Activity Collection System logs, and formal Federal Geographic Data Committee metadata.
This 1-meter by 1-meter cell size backscatter mosaic that was derived from the processed interferometric swath bathymetry data collected in July of 2012 around the northern Chandeleur Islands, Louisiana.
The swath bathymetry data were collected and processed in the ITRF2005 geodetic reference ellipsoid. There are two components to the raw swath file (*.SXR)bathymetry and backscatter. The backscatter component was processed by importing the *.SXR files into SonarWiz5® version 5.06, applying corrections and exporting a final 1 meter mosaic.
20120712
20120804
ground condition
none planned
-88.917567
-88.794042
30.096374
29.940108
USGS Metadata Identifier
USGS:877784c4-0098-4953-89bb-7495c6ad8c7f
ISO 19115 Topic Category
elevation
geoscientificInformation
imageryBaseMapsEarthCover
oceans
General
marine geology
bathymetry
interferometry
swath
Systems Engineering and Assessment
SEA
SWATHplus-M
hydrography
geophysical
U.S. Geological Survey
USGS
Coastal and Marine Geology Program
CMGP
St. Petersburg Coastal and Marine Science Center
SPCMSC
Barrier Island Evolution Research Project
Barrier Island Mapping
12BIM03
backscatter
Geographic Names Information System (GNIS)
Chandeleur Islands
Gulf of Mexico
Chandeleur Sound
Louisiana
None
The U.S. Geological Survey requests that it be referenced as the originator of this dataset in any future products or research derived from these data. These data should not be used for navigational purposes.
U.S. Geological Survey
Nancy T. DeWitt
Geologist
Mailing and physical
600 4th Street South
St. Petersburg
FL
33701
USA
(727) 502-8000
ndewitt@usgs.gov
U.S. Geological Survey, Coastal and Marine Geology Program, St. Petersburg Coastal and Marine Science Center
Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1
The accuracy of the data is determined during data collection. This dataset is from one research cruise and is therefore internally consistent. Methods are employed to maintain data collection consistency aboard the platform. During mobilization, each piece of equipment is isolated to obtain internal and external offset measurements with respect to the survey platform. All the critical measurements are recorded manually and digitally entered into their respective programs. For the interferometric swath bathymetry, offsets between the sonar head and the differential geographic positioning system (DGPS) antennas were measured and entered into the CodaOctopus F190R internal setup program. The DGPS was provided through the OmniSTAR High Performance wide-area GPS service. DGPS is always implemented for navigational accuracy either during acquisition or as a post-processing step. These bathymetric data have not been independently verified for accuracy.
This archive contains the post-processed interferometric swath backscatter data from a single research cruise in July, 2012. Refer to the online data series linkage for field logs, vessel platform descriptions, and other survey information.
This is a TIFF file of the backscatter samples derived from acoustic interferometric swath data collected in July 2012 from around the northern Chandeleur Islands. The backscatter intensity value is displayed as a digital number from 0 to 71 and the mosaic is 1-meter resolution.
The stated horizontal accuracy of the OmniSTAR HP navigation subscription used during swath bathymetry acquisition is reported by the service as +/-15 centimeters (cm) (95 percent of the time). The Coda Octopus F190R IMU, which integrates the OmniSTAR HP position with motion, measures vessel velocity (manufacturer's specified accuracy +/- 0.014 m/s), roll and pitch(+/- 0.025 degrees), heading (1 m baseline 0.1 degrees), and heave (5 percent of heave amplitude or 5 cm).
The stated horizontal accuracy of the OmniSTAR HP navigation subscription used during swath bathymetry acquisition is reported by the service as +/-15 cm (95 percent of the time). The Coda Octopus F190R IMU, which integrates the OmniSTAR HP position with motion, measures vessel velocity (manufacturer's specified accuracy +/- 0.014 meters per second (m/s)), roll and pitch(+/- 0.025 degrees), heading (1 m baseline 0.1 degrees), and heave (5 percent of heave amplitude or 5 cm). The vertical accuracy for the SWATHplus-M system varies with depth and across track range. At 57 m it is accurate to 10 cm vertically.
Swath Bathymetry Acquisition: The interferometric swath bathymetry data were collected aboard the R/V SurveyCat using a SEA SWATHplus-m 234 kHz interferometric sonar system mounted on a sled attached to a rail system, fastened between the catamaran halls allowing the instrument to align directly below the GPS antennae to minimize geometry errors. Boat position and motion data were recorded in real-time using a CodaOctopus F190R wetpod inertial measurement unit (IMU) mounted underwater between the transducer heads to minimize lever arm geometry errors between the observed depths and vessel motion. Real-time corrected positions were acquired via the OmniSTAR HP (High-Precision differential global navigation satellite system) satellite constellation subscription. OmniSTAR HP position correction data and motion data from the IMU were integrated with interferometric soundings in the SWATHplus software package, with positional and calibration offsets pre-defined by a session file (.sxs), allowing for real-time- corrected depths. Prior to deployment, all equipment offsets were surveyed in dry dock with the use of a laser total station. During the survey all swath data were recorded in SEA raw data format (.sxr). A Valeport Mini Sound Velocity Sensor (SVS) was attached to the transducer mount and collected continuous speed of sound (SOS) measurements at the depth of the transducers. These values were directly read and incorporated into the SWATHplus acquisition software giving real-time speed of sound at the transducer while underway. In addition, a separate sound velocity profiler (Valeport miniSVP) was used to collect speed of sound profiles (water surface to seafloor) at intervals throughout the survey.
2012
U.S. Geological Survey
Nancy T. DeWitt
Geologist
mailing and physical
600 4th Street South
St. Petersburg
FL
33701
USA
(727) 502-8000
ndewitt@usgs.gov
Interferometric Swath Bathymetry Acquisition and Processing: Position data recorded by the Coda-Octopus F190R IMU system were corrected in real time via the OmniSTAR HP differential navigation service. The IMU applied real-time motion corrections for heave, roll, and pitch to the vertical component of each position fix. The corrected positions were integrated with the observed bathymetric values to calculate a final position and ellipsoid height representing the elevation of the seafloor with respect to the geodetic reference frame ITRF2005 (ITRF05) across the swath range.
The Systems Engineering and Assessment Ltd program SWATHplus serves as both an acquisition software and initial processing software. Preliminary roll calibration data were collected and processed using SWATHplus and Grid Processor software versions 3.7.17. Instrument offset and calibration values were input into the session file (.sxs). The raw data files (.sxr) were then collected and processed with the updated system configuration file, which contained roll calibration values, measured equipment offsets, acquisition parameters, navigation parameters, speed of sound (SOS) at sonar head, and the SVP cast data. Any acoustic filtering applied in SWATHplus was also written to the processed data file (.sxp). The initial datum for the swath and backscatter data was ITRF05, which is the real-time acquisition datum of OmniSTAR HP position and navigation data.
raw files *.sxr
2012
processed files *.sxp
U.S. Geological Survey
Nancy T. DeWitt
Geologist
mailing and physical
600 4th Street South
St. Petersburg
FL
33701
USA
(727) 502-8000
ndewitt@usgs.gov
Acoustic backscatter analysis: The same raw data files (.sxr) were imported into SonarWiz5® version 5.06, and bottom tracking was applied to define the first returns from the seafloor through the water column directly below the swath transducers. Once the seafloor was defined, sonar beam angle correction was applied to remove the water column from the data and minimize target shadows in the data. A comprehensive backscatter mosaic was created from the individual swath lines and was adjusted for contrast and brightness. The final mosaic was exported in GeoTIFF format and imported into the ArcGIS project where the histogram was adjusted to enhance the display of seafloor surface.
raw files *.sxr
2013
GeoTIFF
U.S. Geological Survey
Nancy DeWitt
Geologist
mailing and physical
600 4th Street South
St. Petersburg
FL
33701
USA
(727) 502-8000
ndewitt@usgs.gov
Added keywords section with USGS persistent identifier as theme keyword.
20201013
U.S. Geological Survey
VeeAnn A. Cross
Marine Geologist
Mailing and Physical
384 Woods Hole Road
Woods Hole
MA
02543-1598
508-548-8700 x2251
508-457-2310
vatnipp@usgs.gov
Raster
Grid Cell
17136
11640
Universal Transverse Mercator
16
0.9996
-87.0
0.0
500000.0
0.0
row and column
1
1
meter
D North American 1983
GRS 1980
6378137.0
298.257222101
North American Vertical Datum 88 (NAVD88)
0.1
meter
Implicit coordinate
U.S. Geological Survey
Nancy T. DeWitt
Geologist
mailing and physical
600 4th Street South
St. Petersburg
FL
33701
USA
(727) 502-8000
ndewitt@usgs.gov
Downloadable Data
This DVD publication was prepared by an agency of the United States Government. Although these data were 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 herein 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.
GeoTIFF
ZIP
50.7
https://pubs.usgs.gov/ds/0847/data/raster/12BIM03_IFS_Mosaic.zip
DVD-ROM
UDF
none
The raster contained in the .zip file is available as a GeoTIFF file. To utilize this data, the user must have a GIS software package capable of reading .tif format. The ASCII text files contained in the .zip archive can be accessed with any standard text file reader.
20201013
U.S. Geological Survey
Nancy DeWitt
Geologist
mailing and physical
600 4th Street South
St. Petersburg
FL
33701
USA
(727) 502-8000
ndewitt@usgs.gov
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
The U.S. Geological Survey requests that it be referenced as the originator of this dataset in any future products or research derived from these data.
None
unclassified
None