U.S. Geological Survey
2018
Multibeam Echosounder, Reson T-20P Southwest Pass site bathymetry (8-m), USGS field activity 2017-003-FA, Mississippi River Delta front offshore of southeastern Louisiana (32-bit GeoTIFF, UTM Zone 16N, NAD 83, NAVD 88 Vertical Datum)
1.0
raster digital data
data release
DOI:10.5066/F7X929K6
Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts
U.S. Geological Survey, Coastal and Marine Geology Program
https://doi.org/10.5066/F7X929K6
https://www.sciencebase.gov/catalog/item/5a946742e4b069906068fb47
Wayne E. Baldwin
Seth D. Ackerman
Charles R. Worley
William W. Danforth
Jason D. Chaytor
2018
High-resolution geophysical data collected along the Mississippi River Delta front offshore of southeastern Louisiana, U.S. Geological Survey Field Activity 2017-003-FA
1.0
data release
DOI:10.5066/F7X929K6
Reston, VA
U.S. Geological Survey
Suggested citation: Baldwin, W.E., Ackerman, S.D., Worley, C.R., Danforth, W.W., and Chaytor, J.D, 2018, High-resolution geophysical data collected along the Mississippi River Delta front offshore of southeastern Louisiana, U.S. Geological Survey Field Activity 2017-003-FA: U.S. Geological Survey data release, https://doi.org/10.5066/F7X929K6.
https://doi.org/10.5066/F7X929K6
https://www.sciencebase.gov/catalog/item/5a8c4bcbe4b00f54eb44044c
High resolution bathymetric, sea-floor backscatter, and seismic-reflection data were collected offshore of southeastern Louisiana aboard the research vessel Point Sur on May 19-26, 2017, in an effort to characterize mudflow hazards on the Mississippi River Delta front. As the initial field program of a research cooperative between the U.S. Geological Survey, the Bureau of Ocean Energy Management, and other Federal and academic partners, the primary objective of this cruise was to assess the suitability of sea-floor mapping and shallow subsurface imaging tools in the challenging environmental conditions found across delta fronts (for example, variably distributed water column stratification and widespread biogenic gas in the shallow subsurface). Approximately 675 kilometers (km) of multibeam bathymetry and backscatter data, 420 km of towed chirp data, and 550 km of multichannel seismic data were collected. Varied mudflow (gully, lobe), prodelta morphologies, and structural features were imaged in selected survey areas from Pass a Loutre to Southwest Pass.
This 8-m per pixel grid represents the processed dual Reson T20P multibeam echosounder bathymetry data collected adjacent to Southwest Pass, the main shipping channel on the southwestern edge of the Mississippi River Delta. The survey was conducted to image a series of previously identified mudflow features in the area. The grid is intended to be used in conjunction with other geophysical and sample data to investigate the morphology and geologic framework of the mudflow features.
Additional information on the field activity is available from https://cmgds.marine.usgs.gov/fan_info.php?fan=2017-003-FA.
20170522
20170523
ground condition
None planned.
-89.555783
-89.452097
28.900822
28.812366
USGS Metadata Identifier
USGS:5a946742e4b069906068fb47
None
U.S. Geological Survey
USGS
Woods Hole Coastal and Marine Science Center
WHCMSC
Coastal and Marine Geology Program
CMGP
Bureau of Ocean Energy Management
BOEM
field activity number 2017-003-FA
GeoTIFF
multibeam echosounder
multibeam bathymetry
Reson
T20P
bathymetry
Marine Geology
ISO 19115 Topic Category
oceans
geoscientificInformation
imageryBaseMapsEarthCover
elevation
USGS Thesaurus
multibeam sonar
bathymetry
marine geophysics
marine geology
None
Gulf of Mexico
Mississippi River Delta front
Southwest Pass
South Pass
Southeast Louisiana
Pass a Loutre
None
sea floor
seafloor
none
2017
none
These data are not to be used for navigation. Mariners should refer to the appropriate nautical chart. Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset.
U.S. Geological Survey
Wayne E. Baldwin
Geologist
mailing and physical
384 Woods Hole Road
Woods Hole
Massachusetts
02543-1598
US
508-548-8700 x2226
508-457-2310
wbaldwin@usgs.gov
https://www.sciencebase.gov/catalog/file/get/5a946742e4b069906068fb47/?name=2017-003-FA_T20P_Bathy_swpasssite_browse.jpg
Thumbnail image of 8-m multibeam echosounder bathymetry data collected adjacent to Southwest Pass on the Mississippi River Delta front offshore of southeastern Louisiana.
JPEG
This grid represents processed dual Reson T20P multibeam echosounder (MBES) bathymetry data gridded at 8-m resolution. Quality control and data processing were conducted to remove spurious points and reduce sound speed artifacts (refraction) using Computer Aided Resource Information System (Caris) Hydrographic Information Processing System (HIPS; versions 10.2 and 10.4). Despite processing, noticeable vessel motion and refraction artifacts remain in the data, particularly in the area surveyed adjacent to Southwest Pass (this data set). Several factors contributed to difficulty during acquisition and processing. As the initial deployment of the dual system configuration on a vessel of opportunity, considerable testing and troubleshooting was expected. Environmental conditions were also challenging over the five-day cruise, including several periods of inclement weather with high winds and waves and the Mississippi River in flood stage, a combination of factors that certainly contributed to the residual artifacts present in the data. While the navigation and attitude data in the backscatter and bathymetry data are identical, the extents of the processed bathymetry grid and backscatter mosaic differ slightly due to differences in processing of the HYPACK HSX bathymetry and SeaBat User Interface s7k backscatter data. Relatively poor MBES data quality at the Southwest Pass site necessitated rejection of larger numbers of soundings than other areas. As such, a larger grid cell size (8 m versus 2 m) was utilized to create a relatively continuous surface, and smooth some of the residual motion artifacts.
Most T20P MBES bathymetry data collected near Southwest Pass during the cruise were used to produce this grid. This includes the time periods: 04:09 (UTC) 5/22/2017 (JD142) - 09:03 5/23/2017 (JD143). The only omissions consisted of data collected during transits, dip lines (lines run generally perpendicular to the shoreline, occupied primarily for seismic-reflection acquisition), and some turns.
Navigation data were acquired using the WGS 84 coordinate system with an Applanix POS MV Wavemaster (model 220, V5), which blends Global Navigation Satellite Systems (GNSS) with acceleration data from a Motion Reference Unit (MRU) and GPS azimuthal heading. The POS MV was configured with two AeroAntenna Technologies GPS antennas located at either end of a 2-m baseline, which was oriented fore and aft and mounted atop the MBES pole, approximately amidships on the starboard side of vessel. DGPS positions were obtained from the primary antenna located on the forward end of the baseline, and the positional offsets between the antenna and the navigational reference point (the POS MV IMU) were accounted for in the Applanix POSView (version 8.60) acquisition software. DGPS positions are horizontally accurate to 0.5 - 2 meters, but accuracy can increase to less than 10 cm after post-processing with Applanix POSPac (version 8.1).
Vertical accuracy of the raw data based on system specifications may be approximately 1 percent of water depth (0.3 to 0.7 m within the area covered by this grid). The Applanix Wavemaster POS MV Attitude and Positioning system, used to correct for vessel roll, pitch, heave, and yaw, has a theoretical vertical accuracy of a few mm. Post-Processed Kinematic (PPK) GPS height corrections (from Applanix POSPac smoothed best estimate of trajectory (SBET) files) were used to reference soundings to the World Geodetic System 1984 (WGS 84) ellipsoid and remove water depth variations caused by tides. Sound speed profiles (more than 70) acquired with an ODIM MVP30 moving vessel profiler were used during post-processing to minimize acoustic refraction artifacts in the bathymetry data. Changes in ship draft due to water and fuel usage were not considered.
U.S. Geological Survey
Unpublished Material
raw MBES data in HSX format
digital data
disc
20170522
20170523
ground condition
Reson T20P multibeam echosounder raw bathymetry
Multibeam echosounder bathymetry, backscatter, and water column data were collected using dual Reson T20P MBES. The pair of Mills Cross transmit and receive arrays were placed side-by-side within a bracket that oriented them at opposing 30 degree angles (relative to horizontal). The bracket was pole-mounted on the starboard side of the R/V Point Sur so that the sonar arrays were oriented athwart ships (primary and secondary arrays facing outward and down to port and starboard, respectively) and located approximately 3.04 m below the waterline when deployed. Vessel navigation and attitude data were acquired with an Applanix POS MV Wavemaster (model 220, V5) configured with two AeroAntenna Technologies GPS antennas located at either end of a 2-m baseline, which was oriented fore and aft and mounted atop the MBES pole approximately amidships on the starboard side of vessel, and the wet pod MRU mounted atop the sonar bracket just aft of the pole. An AML Micro X SV mounted on the sonar bracket monitored sound speed near the sonars during acquisition, and an ODIM MVP30 moving vessel profiler (MVP), mounted on the stern, was used to collect water column sound speed profiles at 1 to 5 hour intervals while underway (See shapefile 2017-003-FA_MVPdata.shp available from the larger work citation). The Reson SeaBat User Interface (version 5.0.0.6) was used to control the sonars, which were operated in intermediate mode at full power (220 db), with frequency modulated pulses between 200 to 300 kHz. The range of the 1024 across track beams formed by the sonars were adjusted manually depending on water depth, and resulted in combined swath widths of 60 to 500 meters or typically 3 to 6 times the water depth. Data were monitored and recorded using the Reson SeaBat User Interface (version 5.0.0.6) and HYPACK/HYSWEEP (version 2017, 17.1.3.0). The SeaBat User Interface logged the navigation, attitude, bathymetry, time-series backscatter, and water column data to s7k format files for each sonar. HYSWEEP logged the navigation, attitude, and bathymetry data for both sonars to a single HSX format file, the time series backscatter data for both sonars to a single 7k format file, and water column data to 7k format files for each sonar. HYPACK HSX data were used to produce the final processed bathymetry grids, and Reson SeaBat User Interface s7k data were used to produce the final processed backscatter mosaics.
Shipboard multibeam bathymetry processing within Caris HIPS (version 10.2) consisted of the following flow:
1) A Caris HIPS project (version 10.2) was created with projection information set to Universal Transverse Mercator (UTM) Zone 16N, WGS 84.
2) A vessel configuration file was created in Caris for the R/V Point Sur, which included relevant linear and angular installation offsets for each T20P unit as well as vendor specified uncertainty values for each of the survey sensors.
3) Each HYPACK HSX file was imported to the new Caris project using the Import/Conversion Wizard.
4) Delayed heave data from raw POS MV files were used to update HIPS survey lines using the import auxiliary data function.
5) Navigation was reviewed and edited as needed using the Navigation Editor tool.
6) Sound velocity correction was applied using the Caris algorithm, a master SVP file containing all the sound velocity profiles collected during the cruise and specifying the nearest in distance method, delayed heave source, and use surface sound speed.
7) Data were merged selecting no tide and the delayed heave source.
8) 5-m resolution Bathymetry Associated with Statistical Error (BASE) surfaces were created to incorporate files for each Julian day as they were processed, and the BASE surfaces were reviewed for inconsistencies and anomalies.
9) The swath and subset editors were used to remove spurious points through manual editing and filter application, and the refraction editor was used to adjust sound speed values in areas where velocimeter data did not adequately correct depth profiles obviously influenced by local anomalies in speed of sound through the water column.
10) Survey lines adjusted for refraction anomalies were remerged, and the respective BASE surfaces were recomputed to reflect the changes. Shipboard processing was primarily focused on QA/QC during acquisition. Editing processes did require trial and error, and were at times iterative.
This process step and all subsequent process steps were conducted by the same person - Wayne Baldwin.
201705
U.S. Geological Survey
Wayne Baldwin
Geologist
mailing and physical address
384 Woods Hole Rd.
Woods Hole
MA
02543-1598
508-548-8700 x2226
508-457-2310
wbaldwin@usgs.gov
Post-cruise processing within Caris HIPS (version 10.4) consisted of the following flow:
1) Post-processed navigation, vessel attitude, and GPS height data from POSPac SBET files, and post-processed rms attitude error data from POSPac smrmsg files were used to update HIPS survey lines using the import auxiliary data function.
2) All lines were updated with Applanix SBET set as the navigation source, and navigation was reviewed and edited as needed using the Navigation Editor tool.
3) GPS tide was computed using delayed heave data, the vessel water line, and a single datum value of 0 m (referencing the data to the WGS 84 ellipsoid).
4) Sound velocity correction was reapplied using the Caris algorithm, the master SVP file containing all the sound velocity profiles collected during the cruise and specifying the nearest in distance method, delayed heave source, and use surface sound speed.
5) Data were remerged selecting the GPS tide and delayed heave sources.
6) Total Propagated Uncertainty (TPU) was computed specifying POSPac smrmsg and delayed heave values.
7) An 8-m resolution Combined Uncertainty Bathymetry Estimator (CUBE) surface was created with all files incorporated in the Southwest Pass survey area, using IHO S-44 Order, Special Order specifications, with a Density and Locale Disambiguation method as a CUBE parameter.
8) Additional editing was conducted using the swath and subset editors to minimize inconsistencies and artifacts, and the CUBE surface was recomputed to reflect the changes.
201711
Gridded surface export and datum transformation:
The Caris CUBE surface was exported from HIPS as an 8-m per pixel Esri ASCII raster (UTM Zone 16N, WGS 84), with pixel values (depths) ranging from -51.91 to -99.46 m. The National Oceanic and Atmospheric Administration's Vertical Datum Transformation tool (VDatum version 3.7) was used to transform the Esri ASCII raster WGS 84, UTM 16N, meters to the North American Datum of 1983 (NAD 83), UTM 16N, North American Vertical Datum of 1988 (NAVD 88), meters, using the GEIOD12B geoid model. The resulting Esri ASCII raster was imported into Global Mapper (version 17.1.0) and exported as the 32-bit floating point GeoTIFF '2017-003-FA_T20P_Bathy_swpasssite.tif', which has pixel values (depths) ranging from -27.32 to -74.92 m.
201801
Added keywords section with USGS persistent identifier as theme keyword.
20200807
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
Pixel
1200
1240
1
Universal Transverse Mercator
16N
0.9996
-87
0
500000
0
row and column
8.0
8.0
meters
D_North_American_1983
GRS_1980
6378137.000000
298.257222
North American Vertical Datum of 1988
0.1
meters
Explicit depth coordinate included with horizontal coordinates
Elevation values in 32-bit GeoTIFF format. Data values represent depths below the North American Vertical Datum of 1988 (NAVD 88). The "no data" value is set to -32767.
U.S. Geological Survey
U.S. Geological Survey - ScienceBase
mailing and physical address
Federal Center
Building 810
Mail Stop 302
Denver
CO
80225
1-888-275-8747
USGS data release 2017-003-FA multibeam echosounder 8-m bathymetry adjacent to Southwest Pass: includes the GeoTIFF 2017-003-FA_T20P_Bathy_swpasssite.tif, the browse graphic 2017-003-FA_T20P_Bathy_swpasssite_browse.jpg, and the Federal Geographic Data Committee (FGDC) Content Standards for Digital Geospatial Metadata (CSDGM) metadata file 2017-003-FA_T20P_Bathy_swpasssite_meta.xml.
Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express 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. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
GeoTIFF
Global Mapper (version 17.1.0)
32-bit GeoTIFF
GeoTIFF grid derived from MBES bathymetry data collected by the U.S. Geological Survey - Woods Hole Coastal and Marine Science Center along the Mississippi River Delta front and the associated metadata.
none
5.7
https://www.sciencebase.gov/catalog/item/5a946742e4b069906068fb47
https://www.sciencebase.gov/catalog/file/get/5a946742e4b069906068fb47
https://doi.org/10.5066/F7X929K6
The first link is to the page containing the data, the second link downloads all data available from the page as a zip file, and the third link is to the publication landing page.
WCS
32-bit GeoTIFF 2017-003-FA_T20P_Bathy_swpasssite.tif provided through a WCS (web coverage service).
https://www.sciencebase.gov/catalogMaps/mapping/ows/5a946742e4b069906068fb47?service=wcs&request=getcapabilities&version=1.0.0
https://www.sciencebase.gov/catalog/item/5a946742e4b069906068fb47
https://doi.org/10.5066/F7X929K6
The first link in the network resources accesses the data through a coverage service, the second is to the page containing the data, and the third link is to the publication landing page.
WMS
32-bit GeoTIFF 2017-003-FA_T20P_Bathy_swpasssite.tif provided through a WMS (web mapping service).
https://www.sciencebase.gov/catalogMaps/mapping/ows/5a946742e4b069906068fb47?service=wms&request=getcapabilities&version=1.3.0
https://www.sciencebase.gov/catalog/item/5a946742e4b069906068fb47
https://doi.org/10.5066/F7X929K6
The first link in the network resources accesses the data through a mapping service, the second is to the page containing the data, and the third link is to the publication landing page.
none
To utilize these data, the user must have software capable of viewing GeoTIFF files, or GIS software capable of utilizing web mapping or coverage services.
20200807
U.S. Geological Survey
Wayne E. Baldwin
Geologist
mailing and physical
384 Woods Hole Rd.
Woods Hole
MA
02543-1598
(508) 548-8700 x2226
(508) 457-2310
wbaldwin@usgs.gov
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
local time