All bathymetric data were collected during USGS cruise 2005-004-FA using a SEA 2000 series 234-kHz swath bathymetric system and an Octopus F180R Attitude and Positioning System. Quality control was conducted during processing of the data. Any spurious data or artifacts were removed or minimized.
This shapefile contains lines 43 - 112 of swath bathymetric data collected on JD 207(07/26/2005) during USGS field activity 2005-004-FA. Lines 1 - 42 were collected during JD206 and completely covered the survey area, however the sidescan-sonar system (Edgetech 4200) failed during survey operations. The backup sidescan-sonar system (Klein 3000 sidescan-sonar) was configured during JD207. As such, the survey area was resurveyed on JD 207 and those data were used for generating bathymetric surfaces and interpretations.
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Navigation was acquired with Wide Area Augmentation System (WAAS), which is accurate to + or - 1 to 2 meters, horizontally. The forward, or primary, Coda Octopus F180R Attitude and Positioning system antenna was used to acquire data and transmit via a network connection to the SEA RTS2000 data collection software. The F180R Attitude and Positioning system uses 2 L1 antennas for position and heading and an Inertial Measurement Unit (IMU) for motion sensing. The F180R IMU is mounted on the rigid bow mount used to deploy the SEA Submetrix 2000 Series bathymetric system, and is located directly above the SEA Submetrix 2000 Series transducers. The F180R antennas are mounted on a rigid horizontal pole, 3 meters above the F180R IMU, offset in a forward/aft configuration. These offsets were corrected within the RTS2000 acquisition software.
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: Unpublished Material
Title: Raw Bathymetric Data
Type_of_Source_Media: online
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 20050726
Source_Currentness_Reference: ground condition of field activity
Source_Citation_Abbreviation: none
Source_Contribution:
Swath-bathymetric and acoustic-backscatter data were acquired with a SEA, Ltd., Submetrix 2000 Series interferometric sonar operating at a 234-kHz frequency. The SEA Submetrix 2000 Series transducers were mounted at the bow of the USGS R/V Rafael. Approximately 37 km of swath bathymetric data were collected.
SEA RTS2000 acquisition software (version year 2005) was used to digitally log the bathymetric data at a maximum 50-meter range (100-meter swath width) and 2048 samples per ping in the SEA SXR format. In shallow water areas, the swath width did not achieve the full 50-meter range, but varied from roughly 5x water depth to the maximum 50-meter range (i.e. swath width varied from approximately 15 meters to 100 meters depending on water depth). Data collection parameters are saved as a RTS2000 session file in SEA SXS format.
An Octopus F180R Attitude and Positioning system (see:
http://www.codaoctopus.com/motion/f180/index.asp) recorded ship motion (heave, pitch, roll, and yaw). These data were transmitted via network connection to the RTS2000 data acquisition software. The Octopus F180R Inertial Measurement Unit (IMU) was mounted directly above the SEA Submetrix 2000 Series transducers, to minimize lever arm offsets that can lead to positioning errors. The F180R uses two L1 antennas for position and heading accuracy. The antennas are mounted on a rigid horizontal pole, 3 meters above the F180R IMU, with a horizontal separation of 1 meter and are offset from the IMU in a forward/aft configuration. The forward offset of the primary antenna from the IMU is 0.5 meters, with no port/starboard offset.
Eight sound-velocity profiles were acquired during survey operations at roughly 1 to 3 hour intervals using an Applied Microsystems SV Plus Velocimeter (Applied Microsystems, 2008). Sound-velocity profiles 1 - 3 were collected during JD 206 for lines 1 - 42. Sound-velocity profiles 4 - 8 were collected during JD207 for lines 43 - 112. Only lines 43 - 112 were used to generate the final bathymetric grid.
Vertical accuracy of the raw data based on system specifications may approximate 1% of water depth, 0.01 to 0.15 meters within the survey area. However, overall vertical accuracies on the order of 0.5 meters are assumed based on the following considerations: WAAS navigation vertical accuracies; the Coda Octopus F180 Attitude and Positioning system, used to correct for vessel roll, pitch, heave, and yaw, has a theoretical vertical accuracy of a few mm; refraction artifacts were minimized by acquiring a range of sound velocity profiles with a hand-casted Applied MicroSystems SV Plus sound velocimeter during the survey. Changes in ship draft due to water and fuel usage were not considered. Vertical resolution is on the order of 0.1 meters.
Process_Step:
Process_Description:
Converting Raw (SXR) to Field-Processed (SXP) Files:
Raw SXR bathymetry data were acquired with the SEA RTS2000 (version year 2005) software and used to generate field-processed SEA RTS2000 SXP files. The following information was stored within the RTS2000 session files and applied to the raw bathymetric soundings: eight sound velocity profiles to minimize refraction artifacts due to fluctuations from the speed of sound in the water column, roll offsets calculated during pre-survey patch test, draft of the transducer below the water line, and the measured angles and relative positions of the swath bathymetric transducers. The RTS2000 software applies the pitch, roll, heave, yaw and heading data supplied by the F180R IMU, to compensate depth solutions across the swath for any ship motion. Some bathymetric filtering was applied during acquisition, however final processing, filtering and editing were completed with The University of New Brunswick, Ocean Mapping Group (OMG) SwathEd software suite (see process step 2).
Jane F. Denny performed this and all subsequent process steps.
Process_Date: 2005
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Jane F. Denny
Contact_Organization: U.S. Geological Survey
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Road
City: Woods Hole
State_or_Province: Massachusetts
Postal_Code: 02543
Country: USA
Contact_Voice_Telephone: 508-548-8700 x2311
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: jdenny@usgs.gov
Process_Step:
Process_Description:
Generating Bathymetric Grid: University of New Brunswick, Ocean Mapping Group (OMG) SwathEd Multibeam Processing Software (Beaudoin, 2002)
Bathymetric data (raw SXR files), sound velocity profiles, and system configuration information (antenna offsets, transducer offsets, water level, attitude and positioning) were used to generate a composite bathymetric grid using the University of New Brunswick's Ocean Mapping Group (OMG) SwathEd multibeam processing software. The raw Submetrix 2000 Series data were "unraveled" and reformatted into the OMG format. This process creates several files on disk:
a) bathymetric soundings (*.merged) b) raw backscatter (*.ss) c) navigation (*.ascii_nav and *.nav) d) parameter files describing the configuration of the system (i.e. offsets between motion reference unit and GPS antenna, etc.). This process also incorporates the sound velocity profiles in order to properly account for any refraction due to fluctuations in the speed of sound within the water column.
Process_Date: 2005
Process_Step:
Process_Description:
Reformatting Navigation:
A C-shell script was used to reformat the ASCII text files (output of the unravel) to include: easting, northing, line number, Julian day, hour, minute, second, longitude, latitude, and concatenate the line files into one comma-delimited ASCII text file.
Process_Date: 2005
Process_Step:
Process_Description:
The text file (*.csv) was imported into Esri ArcMap 9.0 using Tools - Add XY Data and converted to an event theme. The event theme was then saved to a point shapefile and the projection was defined as Geographic Coordinate System, WGS84 (GCS_WGS_1984). The point shapefile was visually inspected for spurious data points and these data points were manually deleted.
Process_Date: 2005
Process_Step:
Process_Description:
The point shapefile containing 10-second navigation was used as an input for a VACExtras (version 1.8), a VB collection of tools developed by VeeAnn Cross (USGS-WHSC), which converts point data to a new polyline shapefile, based on the order of records contained within one attribute field. The line number field was used to define the point grouping to create a line.
Process_Date: 2005
Process_Step:
Process_Description:
System, Freq, Cruise ID, Acq_Date, and Jday fields were added to the attribute table within ArcMap 9.0. The length of each line segment was calculated and included in a new attribute field (Length) using XTools Pro for ArcGIS desktop (version 5.3.0), specifying UTM Zone 19 N, WGS84 - meters.
Process_Date: 2005
Process_Step:
Process_Description:
ArcGIS 9.3, Xtools 7.1.0 (Build 738) was used to convert polyines to points using Xtools, Feature Conversion, Convert Features to Points, generating a new shapefile. Xtools was then used to add X,Y coordinates to the new shapefile table, using Xtools, Table Operations, Add X,Y,Z coordinates. The table was then exported to a text file using, Xtools, Table Operations, Export table to txt. The txt file was saved as a *.csv. The *csv can then be used outside of the ArcGIS 9.3 environment to generate trackline data, if neeed.
Process_Date: 2014
Process_Step:
Process_Description:
The online links to the data were updated to reflect the new server hosting the data. Additionally, other small edits could be made to the metadata, such as modifying http to https where appropriate. The metadata date (but not the metadata creator) was edited to reflect the date of these changes.
Process_Date: 20170406
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
Process_Step:
Process_Description: USGS Thesaurus keywords added to the keyword section.
Process_Date: 20180720
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
Process_Step:
Process_Description:
Added keywords section with USGS persistent identifier as theme keyword.
Process_Date: 20200908
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
