These swath bathymetry data were collected at 200 meter line spacing. The M/V Scarlet Isabella can only survey in water depths greater than 8 meters, so there are some gaps in the survey lines where the vessel had to avoid crossing shallow shoals. Most of the gaps were planned with breaks in tracklines or maneuvers around the shoals. Most of the data were acquired roughly parallel to the orientation of Assateague Island at an average speed of 5 knots. Line numbering begins at line 1 and ends at line 183. Any spurious bathymetry navigation data points were removed during processing.
This shapefile includes trackline navigation from all the swath bathymetric data that was collected within the survey area. However, only quality sonar data along the main survey lines were included in the final bathymetry grid. Noisy or poor quality data were not included in the grid, but the line navigation are included in this shapefile. Data along tie and transit lines were not included in the final grid or in the navigation shapefile.
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Navigation data were acquired in WGS 84 coordinate system with an Applanix Wavemaster POS MV, which blends Global Navigation Satellite Systems (GNSS) with acceleration data from a Motion Reference Unit (MRU) and GPS azimuthal heading. The POS MV uses a dual antenna array with a designated primary and secondary antenna. Positions from the primary (forward) Applanix antenna were sent via Ethernet satellite link (from a KVH Mini-VSAT Broadband receiver) to shore stations in MD and VA. Returned Radio Technical Commission for Maritime Services (RTCM) 3.1 position corrections were passed through to the Applanix Wavemaster and applied to the Submetrix System for Real Time Kinematic (RTK) position solutions (accurate to less than 1 m, horizontally). Backup Differential Global Positioning System + Wide Area Augmentation System (DGPS+WAAS), which is accurate to within 2 m horizontally, were also acquired using an Ashtech Proflex 800; however, the backup DGPS and WAAS data were not implemented into the bathymetry data since the primary POS MV positioning provided continuous data throughout the survey. Positional offsets from the primary antenna to the MRU were corrected within the BathySwath acquisition software.
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: Unpublished Material
Title: raw swath bathymetry data
Geospatial_Data_Presentation_Form: vector digital data
Type_of_Source_Media: disc
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20150610
Ending_Date: 20150714
Source_Currentness_Reference:
ground condition; data were not collected on 20150628 (transition between Legs 1 and 2 of the survey).
Source_Citation_Abbreviation: raw bathymetry
Source_Contribution:
USGS used a 234 kHz Systems Engineering and Assessment Ltd. (SEA) SWATHplus-M (now Bathyswath) interferometric sonar pole-mounted on the port side of the M/V Scarlett Isabella. Survey lines were run at an average speed of 5 knots and were spaced 200 m apart in the nearshore to approximately 3-km apart in the offshore. Full data coverage was obtained for sidescan sonar data, but not for bathymetric data. The SEA SWATHplus-M operates at a variable range (increased or decreased manually depending on water depth, but generally 85 m on both sides). The system was operated with a transmit power of 80 percent, a transmit length of 43 cycles, and 4096 samples per channel. Sound-velocity profiles were collected continuously with an ODIM MVP30 moving vessel profiler. Tides were corrected using a zone tidal model with observed tides from gauges in Atlantic City, NJ; Lewes, DE; Chesapeake Bay-Bridge-Tunnel, VA; and Duck, NC.
Process_Step:
Process_Description:
Survey navigation information is stored within each raw (.sxr) data file. Each raw SWATHPlus bathymetric sonar file (.sxr) was converted to a SWATHplus processed file (.sxp) using SEA SWATHplus Swath Processor (vers. 3.10.6.0). This step and subsequent steps were performed by Wayne Baldwin.
Process_Date: 2015
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Wayne Baldwin
Contact_Position: Physical Scientist
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:
A new Computer Aided Resource Information System (CARIS) Hydrographic Information Processing System (HIPS) project (vers. 9.0.14) was created with projection information set to Universal Transverse Mercator (UTM) Zone 18N, WGS 84. Each SWATHplus processed file (sxp) was imported to the new CARIS project using the Import/Conversion Wizard. Navigation was checked and edited as needed using the Navigation Editor tool.
Process_Date: 2015
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Wayne Baldwin
Contact_Position: Physical Scientist
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:
AWK, Python and Shell scripts were used to extract and reformat the navigation fixes stored in the CARIS HIPS database and add them to a geospatial SQLite (version 3.7.9) database. The processing flow for this step follows:
A. 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.
B. 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.
C. 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 trackline navigation for each survey line.
D. When all of the survey lines have been processed into SQLite database, a polyline shapefile is exported from the database using the spatialite_tool command (Spatialite version 3.0.1).
Steps B, C and D were all run within a shell script called printfnavconv.
Process_Date: 2015
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Wayne Baldwin
Contact_Position: Physical Scientist
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:
XTools Pro (version 12.0) for ArcGIS desktop was used (TABLE OPERATIONS - TABLE RESTRUCTURE) to rename long attribute headings in the polyline shapefile's attribute table. Table attributes for the survey line ('LineName' remained the same), Year and Julian day ('Year_JD_init' was changed to 'Yr_JD_ini') survey line started, Julian day and UTC time ('JD_UTC_init' was changed to 'JD_UTC_ini') survey line started, Year and Julian day that the survey line ended ('Year_JD_end' was changed to 'Yr_JD_end'), Julian day and UTC time that the survey line ended ('JD_UTC_end' remained the same), survey ID ('SurveyID' remained the same), survey vessel name ('VehicleID' remained the same), device used to collect the data ('DeviceID' remained the same) and length field ('Length_km' remained the same).
Process_Date: 2015
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Edward M. Sweeney
Contact_Position: Physical Scientist
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 x2256
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: emsweeney@usgs.gov
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: 20170419
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
