Attribute_Accuracy_Report:
The accuracy of the data was determined during data collection. This dataset was from one research cruise and was therefore internally consistent. Methods were employed to maintain data collection consistency aboard the platform. During mobilization, each piece of equipment was isolated to obtain internal and external offset measurements with respect to the survey platform. All the critical measurements were recorded manually and digitally entered into their respective programs. For the interferometric swath bathymetry, offsets between the sonar head and the Differential Global Positioning System (DGPS) antennas were measured and entered into the Coda Octopus F190R+ internal setup program. The DGPS correction was obtained from Marinestar High-precision (HP) differential global navigation satellite system, a satellite positioning service, from Fugro, Incorporated (Inc.). This signal was received through the Coda Octopus F190R+ GPS antennas. These bathymetric data have not been independently verified for accuracy. The dataset was collected in the native format of WGS84 (G1762), which is equivalent to ITRF08.
This file includes the post-processed bathymetric data (x,y,z) collected during an interferometric swath bathymetry survey (2016-347-FA, subFAN 16BIM04) acquired from nearshore waters surrounding Ship Island and Horn Island, Mississippi. Refer to the supplemental information section of the data release for field logs, vessel platform descriptions, and other survey information.
These are complete, post-processed xyz bathymetric data points from interferometric swath data collected in July 2016 from the nearshore areas of Ship and Horn Islands, Mississippi.
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Navigation information was recorded in real-time kinematic mode via the Coda Octopus F190R+ Precision Attitude and Positioning System. Differential GPS correction was obtained through the Marinestar HP broadcast subscription from Fugro, Inc. The manufacturer's stated horizontal accuracy is 10 centimeters (cm) 95% of the time. The trackline position data were recorded using HYPACK version 16.1.1.0 hydrographic acquisition and processing software.
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report:
The manufacturer's stated vertical accuracy of Marinestar GPS subscription is 15 cm, 95% of the time. The Coda Octopus F190R+ inertial measurement unit (IMU), which integrates the Marinestar position with motion, measures vessel velocity (+/- 0.014 meters/second [m/s]), roll and pitch (less than 0.025 degrees), heading (1 m baseline 0.1 degrees), and heave (5 cm per m of depth). The vertical accuracy for the SWATHplus-H system varies with depth and across track range.
Vertical transformation error reported by VDatum version 3.6 is the following:
Transformation from ITRF08 to ITRF00 (equivalent to WGS84 [G1150]) is 0.00 m or 0.00 cm for the vertical area named conus (Continental U.S.).
Transformation from ITRF00 to NAD83, NAVD88 with respect to GEOID12B is 0.0762 m or 7.62 cm for the vertical area named GEOID12B.
Transformation from NAD83, NAVD88 with respect to GEOID12B to NAD83, MLLW is 0.163 m or 16.30 cm for the vertical area named LAmobile02-8301.
Process_Step:
Process_Description:
Swath Bathymetry Acquisition: The interferometric swath bathymetry data were collected aboard the R/V Sallenger in July 2016, using the SEA SWATHplus-H 468 kHz interferometric sonar system. The transducer system was fastened to a static pole mount deployed over the starboard side gunnel. The Novatel GPS antennas were mounted atop the cabin. Boat position and motion data were recorded in real-time using a Coda Octopus F190R+ wetpod IMU. The IMU was mounted underwater between the transducer heads to minimize lever arm geometry errors between observed depths and vessel motion. Real-time corrected positions were acquired via Marinestar HP DGPS subscription service from Fugro, Inc. Marinestar HP position correction data and motion data from the IMU were integrated with interferometric soundings using Bathyswath software, version 3.10.2.0, with positional and calibration offsets pre-defined by a session file (.sxs), allowing for real-time-corrected depths. Before deployment, all equipment offsets were measured. During the survey, all swath tracklines were recorded in Bathyswath raw data format (.sxr). A Valeport Mini Sound Velocity Sensor (miniSVS) 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 Bathyswath raw data format during acquisition, providing a real-time speed of sound at the transducer while underway. In addition, a separate YSI Castaway Conductivity, Temperature, and Depth (CTD) probe was used to collect speed of sound profiles (water surface to seafloor) throughout the survey.
Process_Date: 2016
Source_Produced_Citation_Abbreviation:
raw data files including: Bathyswath specific (*.sxs, *.sxr), F190R+ specific (*.csv, *.mcom), and Castaway CTD (*.ctd, *.svp, *.csv)
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Jake Fredericks
Contact_Position: Physical Scientist/Hydrographic Tech
Contact_Address:
Address_Type: mailing and physical
Address: 600 4th Street South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: (727) 502-8033
Contact_Electronic_Mail_Address: jfredericks@usgs.gov
Process_Step:
Process_Description:
Swath Bathymetry Processing: Data were collected with Bathyswath 3.10.2, an acquisition and initial processing program. Preliminary roll calibration trackline data were collected and processed using Bathyswath Swath Processor version 3.10.2.0 and Bathyswath Grid Processor software version 3.10.0.0. Instrument offsets and calibration values were input into the session file (.sxs) and the raw data files (.sxr) were then processed using the updated system configuration file containing roll calibration values, measured equipment offsets, acquisition parameters, navigation and motion from the F190R+, SOS at the sonar head, and SVP cast data. Any calibration offsets and acoustic filtering utilized in Bathyswath was then applied to each raw data file to create a processed data file (.sxp), and then imported into advanced sounding data processing software CARIS HIPS and SIPS (CARIS) version 9.1. The initial real-time processing datum for the swath and backscatter data was WGS84(G1762), which is the acquisition datum for Marinestar HP position and navigation data.
Within CARIS, outliers for the navigation data and processed soundings were removed using program filters. Any remaining data outliers were then removed manually. A CARIS BASE surface with associated CUBE sample surface was created from the edited soundings. A CUBE hypothesis is the estimated value of a grid node representing all the soundings within a chosen resolution or grid-cell size (for example, 5 m) weighted by uncertainty and proximity, giving the final value as a "sample" of the data within the specific grid cell. This algorithm allows for multiple grid-node hypotheses to be verified or overridden by the user while maximizing processing efficiency. A final visual inspection of the dataset in addition to Quality Control and Quality Assurance (QA/QC) procedures were implemented to ensure all outliers and erroneous data points had been removed from the final BASE surface. In order to provide the dataset in a non-proprietary format, the final x,y,z data were exported as an ASCII comma-separated file.
Source_Used_Citation_Abbreviation:
raw data files including: Bathyswath specific (*.sxs, *.sxr), F190R+ specific (*.csv, *.mcom), and Castaway CTD (*.ctd, *.svp, *.csv)
Process_Date: 2016
Source_Produced_Citation_Abbreviation: 16BIM04_IFB_ITRF08_5m_xyz.txt
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Jake Fredericks
Contact_Position: Physical Scientist/Hydrographic Technician
Contact_Address:
Address_Type: mailing and physical
Address: 600 4th Street South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: (727) 502-8033
Contact_Electronic_Mail_Address: jfredericks@usgs.gov
Process_Step:
Process_Description:
Trackline file export: The interferometric swath trackline file was produced by creating an HOB file in CARIS version 10.2.1, which could then be exported as a shapefile. This shapefile was then imported into Arcmap version 10.4.1 and additional attributes were added for the data release. The resultant polyline shapefile was then projected in ITRF00 and NAD83, respectively.
Source_Used_Citation_Abbreviation:
16BIM04_Tracklines.hob
16BIM04_IFB_ITRF00_Level_004_tracklines.shp
Process_Date: 2016
Source_Produced_Citation_Abbreviation:
Ship_Horn_Island_2016_IFB_ITRF00_tracklines.zip
Ship_Horn_Island_2016_IFB_NAD83_tracklines.zip
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Nancy T. DeWitt
Contact_Position: Geologist
Contact_Address:
Address_Type: Mailing and physical
Address: 600 4th Street South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: U.S.
Contact_Voice_Telephone: (727) 502-8000
Contact_Electronic_Mail_Address: ndewitt@usgs.gov
Process_Step:
Process_Description:
VDATUM Conversion: Using the National Oceanic and Atmospheric Administration (NOAA) VDatum version 3.6 transformation software (
http://vdatum.noaa.gov/) the IFB dataset was transformed from ITRF08 to ITRF00 to match the SBB dataset. The dataset was then transformed from ITRF00 to NAD83 and NAVD88 with respect to the GEOID12B model and finally into NAD83 and MLLW, for inclusion in this data release. The datasets were renamed for this data release.
Ship_Horn_Island_2016_IFB_ITRF00_5m_xyz.txt
Ship_Horn_Island_2016_IFB_NAD83_MLLW_5m_xyz.txt
Ship_Horn_Island_2016_IFB_NAD83_NAVD88_GEOID12B_5m_xyz.txt
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Nancy T. DeWitt
Contact_Position: Geologist
Contact_Address:
Address_Type: Mailing and physical
Address: 600 4th Street South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: U.S.
Contact_Voice_Telephone: (727) 502-8058
Contact_Electronic_Mail_Address: ndewitt@usgs.gov
Process_Step:
Process_Description:
Added keywords section with USGS persistent identifier as theme keyword.
Process_Date: 20201013
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: VeeAnn A. Cross
Contact_Position: Marine Geologist
Contact_Address:
Address_Type: Mailing and Physical
Address: 384 Woods Hole Road
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: 508-548-8700 x2251
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: vatnipp@usgs.gov
