Multibeam echosounder (MBES) data were collected almost continuously during daylight survey operations, usually 8-10 hours per day, but acquisition was suspended briefly during file changes or for longer periods during turns and system calibration, malfunction, or troubleshooting. Gaps between the polyline features in this shapefile reflect those time periods where data were not recorded.
Data were not collected on October 23, 2017 while the base of operations was moved from Bullfrog, UT in the northeast to Page, AZ in the southwest. Data were not collected between Nov 10 and 14 because of a cable failure of the Applanix navigation and attitude system. Operations resumed (and were completed) November 15, 2017 after installation of the new cable.
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
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 midships 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).
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: Unpublished Material
Title: raw MBES data in s7k format
Geospatial_Data_Presentation_Form: digital data
Type_of_Source_Media: disc
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20171008
Ending_Date: 20171115
Source_Currentness_Reference: ground condition
Source_Citation_Abbreviation: RAW RESON T20-P MULTIBEAM ECHOSOUNDER FILES
Source_Contribution:
Multibeam echosounder (MBES) bathymetry and backscatter data were collected using dual-head Reson T20-P sonars. The pair of mills cross transmit and receive arrays were mounted 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 Stephens 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 1.235 m below the waterline when deployed. Vessel navigation and attitude data were acquired using 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 midships on the starboard side of vessel, and the wetpod 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 AML Minos X SVPT deployed using an electric downrigger mounted on the port quarter was used to collect water column sound speed profiles 1 to 3 times each survey day (See shapefile 2017-049-FA_SVPdata.shp available from the larger work citation). The Reson SeaBat User Interface (UI)(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 200 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. The line files were created by the Reson UI using the following naming convention: YYYYMMDD_HHMMSS_M/S. The line files were appended with a "M" and "S" suffix to denote the port (or primary) "M" and "S" starboard (or secondary) sonar heads
Process_Step:
Process_Description:
PROCESSING STEP 1: CARIS HIPS DATA PROCESSING.
Multibeam bathymetry processing within CARIS HIPS (version 10.2) during the survey consisted of the following flow:
1) Vessel configuration files were created in CARIS for the port ("M"=main, or primary) and starboard ("S"=secondary) sonars (RVStephens_DualT20P_M.hvf, and RVStephens_DualT20P_S.hvf) which included relevant, linear and angular installation offsets for each T20-P unit as well as vendor specified uncertainty values for each of the survey sensors.
2) A CARIS HIPS project (version 10.2) was created with projection information set to Universal Transverse Mercator (UTM) Zone 12N, NAD 83. Separate HIPS projects were created for the Port (M), and Starboard (S) line files using the two vessel configuration files in #1 above.
3) Each Reson s7k file (M and S) were imported to the new CARIS projects (M and S respectively) 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 survey 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) 2-m resolution Swath Angle Weighted (SWATH) surfaces were created to incorporate all the files (M and S) as they were processed, and the SWATH 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, which were 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 SWATH surfaces were recomputed to reflect the changes. Processing during the survey was primarily focused on QA/QC during acquisition. Editing processes did require trial and error, and were at times iterative. The contact person for Processing steps 1 and 2 is Brian Andrews.
Process_Date: 201711
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Brian Andrews
Contact_Position: Geographer
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Country: US
Contact_Voice_Telephone: 508-548-8700 x2348
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: bandrews@usgs.gov
Process_Step:
Process_Description:
PROCESSSING STEP 2: APPLY POST PROCESSED SBET FILES.
Post-survey 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) Navigation source was set to Applanix SBET, 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 (vertically 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 survey 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) 2-m resolution SWATH surfaces using both the M and S files were created using the Swath Angle method and a maximum footprint of 9.
7) Additional editing was conducted using the swath and subset editors to minimize inconsistencies and artifacts, and the SWATH surface was recomputed to reflect the changes. Finally, small "no data" holidays were filled using the "Fill Raster Holiday" tool and a 5x5 cell filter using data from a minimum of 5 neighboring cells.
Process_Date: 201804
Process_Step:
Process_Description:
PROCESSING STEP 3: EXTRACT NAVIGATION.
Use Caris printfNav and Python to extract and reformat the navigation fixes stored in the Caris HIPS database and add them to a geospatial SQLite (version 3.21.0) database:
1) Extract navigation for each line in Caris HDCS directory using the Caris program printfNav for all the lines. (Extracted navigation file is tab-delimited in format YYYY-JD HH:MM:SS:FFF DD.LAT DD.LONG SSSSS_VVVVV_YYYY-JD_LLLL AR where YYYY=year, JD=Julian Day, HH=hour, MM=minute, SS=seconds, FFF=fractions of a second, DD.LAT=latitude in decimal degrees, DD.LONG=longitude in decimal degrees, SSSSS=survey name, VVVVV=vessel name, LLLL=linename, AR=accepted or rejected navigation fix). This step creates TXT navigation files for each survey line in the Caris project.
2) A Python script (pySQLBathNav) runs on the navigation TXT files, creating a new line in the SQLite database (which is created if it does not already exist) for each record, with new fields survey ID, vessel name, and system name. The pySQLBathNav script creates both point and polyline navigation for each survey line. The contact person for Processing steps 3-5 is Wayne Baldwin.
Process_Date: 201804
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Wayne E. Baldwin
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical
Address: 384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: (508) 548-8700 x2226
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: wbaldwin@usgs.gov
Process_Step:
Process_Description:
PROCESSING STEP 4: CREATE ESRI SHAPEFILE CONTAINING THE POLYLINE DATA:
The T20P polyline features were added (Add Data) into ArcMap (version 10.3.1) from the SQLite database, then exported (Right click on database feature class >Data> Export Data) to the new Esri polyline shapefile 2017-049-FA_T20P_Tracklines.shp. Create new string attributes "SurveyID", "VehicleID, and "DeviceID" and populate using the "field calculator" context menu.
Process_Date: 201804
Process_Step:
Process_Description:
PROCESING STEP 5: RENAME SHAPEFILE ATTRIBUTE TABLE FIELDS:
XTools Pro (version 12.0) for ArcGIS desktop was used (TABLE OPERATIONS - TABLE RESTRUCTURE) to rename some attribute field headings in the polyline shapefile's attribute table. 'Year_JD_ini' was changed to 'YJD_start', 'JD_UTC_ini' was changed to 'JDUT_start', 'Year_JD_end' was changed to 'YJD_end', and 'JD_UTC_end' was changed to 'JDUT_end'. A new attribute field "Length_km" was added to the shapefile attribute table populated with the length in kilometers of the feature using the "calculate geometry" context menu in ArcMap (v.10.3.1). The UTM 12 WGS 84 coordinate system was used to calculate the lengths of each line. The remaining field headers were unchanged.
Process_Date: 201804
Process_Step:
Process_Description:
Added keywords section with USGS persistent identifier as theme keyword.
Process_Date: 20200806
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
