Multibeam echosounder (MBES) data were collected almost continuously throughout the cruise, 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 or were held from publication. The columns "LineName" and "LineName7k" in the attribute table contain the filenames for equivalent MBES files recorded in the HYPACK HYSWEEP (HSX format) and ResonUI (s7k format) acquisition software, respectively. Navigation for each of the file formats is identical (though files may differ in start or end times by several seconds) and represented by a single polyline. In some instances, loading of the POSPac SBET data necessitated splitting the HIPS survey lines due to small gaps in the post-processed data; e.g. a and b files for 329_0409, 326_0842, 322_1355, and 322_1935; Additionally, SBET data would not load into data from 5/21/2017 (JD141) between 02:27 and 13:08, and GPS heights were loaded from the raw POS MV files. No equivalent s7k format files were recorded for HSX lines 001_0227, 002_0242, 003_0257, or 101_1827.
This shapefile includes trackline navigation for all the multibeam echosounder data collected during the cruise, except for the time periods 19:19 (UTC) 5/21/17 (JD141) - 02:20 5/22/17 (JD142) and 22:52 5/23/17 (JD143) - 23:03 5/23/17 (JD143), which were held from publication at the request of a cooperating agency. While the line navigation for all the data are included in this shapefile, all the data are not included in the final bathymetry grids or backscatter mosaics.
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 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).
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: Unpublished Material
Title: raw multibeam echosounder data
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: 20170521
Ending_Date: 20170526
Source_Currentness_Reference: ground condition
Source_Citation_Abbreviation: Reson T20P multibeam echosounder data
Source_Contribution:
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.
Process_Step:
Process_Description:
Shipboard multibeam processing within Caris HIPS (version 10.2) consisted of the following flow:
1) Caris HIPS projects (version 10.2) were created to process T20P data in the HSX and s7k formats. Projection information was set to Universal Transverse Mercator (UTM) Zone 16N, WGS 84 in each.
2) Vessel configuration files were created in each Caris project 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) Raw files were imported to the Caris projects 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.
This process step and all subsequent process steps were conducted by the same person - Wayne Baldwin.
Process_Date: 20175
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Wayne Baldwin
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
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:
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 (In some instances, loading of the POSPac SBET data necessitated splitting the HIPS survey lines due to small gaps in the post-processed data; e.g. a and b files for 329_0409, 326_0842, 322_1355, and 322_1935; Additionally, SBET data would not load into data from 5/21/2017 (JD141) between 02:27 and 13:08, and GPS heights were loaded from the raw POS MV files).
2) Where applicable, lines were updated with Applanix SBET set as the navigation source, and navigation was reviewed and edited as needed using the Navigation Editor tool.
Process_Date: 201711
Process_Step:
Process_Description:
Use AWK, Python, and Shell scripts 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 the directory of TXT navigation files for each survey line in the Caris project
2) The output TXT files from the printfNav process are parsed to remove rejected navigation records then reformatted into CSV files containing additional fields for survey ID, vessel name, and system name using Shell and AWK scripts
3) A Python script (pySQLBathNav) runs on each reformatted CSV file parsing the file from each record and adding points to a SQLite database (which is created if it does not already exist). The pySQLBathNav script creates both point and polyline navigation for each survey line.
Process_Date: 201712
Process_Step:
Process_Description:
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 2017-003-FA_T20P_Tracklines.shp
Process_Date: 201712
Process_Step:
Process_Description:
Create field for Reson SeaBat User Interface s7k filenames in shapefile attribute table:
A new attribute field named "LineName7k" was added to the shapefile attribute table and manually populated with the name of the Reson SeaBat User Interface s7k filename corresponding to the Hypack Hysweep HSX file listed in the "LineName" field.
Process_Date: 201712
Process_Step:
Process_Description:
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'. The remaining field headers were unchanged.
Process_Date: 201712
Process_Step:
Process_Description:
Added keywords section with USGS persistent identifier as theme keyword.
Process_Date: 20200807
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
