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 from some survey lines were omitted where they overlapped with equal or better quality data (for example lines l148f2 and l19f3 are nearly collocated and only data from l148f2 are included in the grid because attitude positioning was not useable from l19f3). 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 was acquired with a Coda Octopus F185 Differential Global Positioning System + Wide Area Augmentation System (DGPS+WAAS), which is accurate to + or - 1 to 2 meters, horizontally and RTK positioning from an Ashtech Proflex 800, which is accurate to less than 1-meter, horizontally. X,Y data are referenced to WGS84. The SWATHPlus transducers were mounted on a rigid pole, approximately 4.195 m below the water line, along the port side of the M/V Scarlett Isabella. The DGPS antenna and an Ashtech ProFlex 800 RTK GPS were located on the same pole approximately 4.6m above the sea surface. RTCM corrections were being delivered via the web (ethernet) to the Ashtech ProFlex 800 from shore stations in MD and VA (ethernet satellite link is from a KVH Mini-VSAT Broadband receiver). The RTK corrections were passed through to the F185R giving the submetrix system kinematic (x,y) positioning accuracy from Julian Day 170 and later. Lines (l1f1-l7f1) collected prior to 20140719 at 12:40:00 UTC were recorded with WAAS-enabled DGPS because the F185 was not receiving RTCM corrections from the Ashtech ProFlex800. Positional offsets from antennae to MRU were corrected within the SWATHPlus acquisition software.
WAAS enabled DGPS accuracy is estimated to be less than 3 m and the accuracy of RTK-GPS is estimated to be less than 1 m.
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: Unpublished Material
Title: raw swath navigation
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: 20140618
Ending_Date: 20140722
Source_Currentness_Reference:
ground condition; data were not collected on 20140702-20140704; 20140709; and 20140714-20140715 due to weather.
Source_Citation_Abbreviation: raw bathymetry
Source_Contribution:
USGS used a 234 kHz Systems Engineering and Assessment Ltd. (SEA) SWATHplus interferometric sonar 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 frequency of 234 kHz and 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:
2014-002-FA: Raw to Processed Conversion: 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 (ver. 3.10.04).
Process_Date: 2014
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Elizabeth Pendleton
Contact_Organization: U.S. Geological Survey
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) 548-8700x2259
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: ependleton@usgs.gov
Process_Step:
Process_Description:
CARIS Processing: A new Computer Aided Resource Information System (CARIS) Hydrographic Information Processing System (HIPS) project (ver. 9.0) was created with projection information set to Universal Transverse Mercator (UTM) Zone 18, WGS84. 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: 2014
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Seth Ackerman
Contact_Organization: U.S. Geological Survey
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) 548-8700x2315
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: sackerman@usgs.gov
Process_Step:
Process_Description:
Perl and AWK (no version) programming scripts were used to extract and subsample the navigation fixes stored in the CARIS HIPS database. The processing flow for this step follows:
A. Extract navigation for each line in CARIS HDCS directory using Perl script do_CARIS_nav3.pl (which runs the CARIS program printfnav for all the lines in the HDCS dir). (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 file combined.txt
B. The navigation files extracted from CARIS HIPS contained 4-5 navigation fixes per second. These files were subsampled to produce files containing 1 fix per second using AWK to remove the fractions-of-a-second from the time column then grabbing the first occurrence of each second. AWK was also used to eliminate spurious fixes outside the survey area and reformat the navigation for conversion from comma separated value (CSV) data to Esri point feature class
Process_Date: 2014
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Seth Ackerman
Contact_Organization: U.S. Geological Survey
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 x2315
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: sackerman@usgs.gov
Process_Step:
Process_Description:
In ArcCatalog (version 10.2), navigation text in CSV format was converted to a point feature class by right-clicking on the comma separated value text file -- Create Feature Class -- from XY table using the defined projection Geographic (Decimal_Degrees_WGS84.prj).
Process_Date: 2014
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Seth Ackerman
Contact_Organization: U.S. Geological Survey
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
Country: USA
Contact_Voice_Telephone: 508-548-8700 x2315
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: sackerman@usgs.gov
Process_Step:
Process_Description:
VAC Extras tool (version: 4.1 FeatConv - Points to Line v2; USGS in-house software) was then used within ArcMap (version 10.2) to convert the navigation points to a trackline shapefile. The 'uniqueline' field was used to define which points were used to generate each polyline feature, and the first occurrence of fields 'linename', 'yrjd', 'jd_time', 'vessel', and the last occurrence of 'jd_tim_end' were chosen to be included as attributes in the output shapefile. The trackline shapefile was checked to ensure there were no severely spurious navigation fixes. XTools Pro (version 10.2.1257) for ArcGIS desktop was used (Table Operations - Table Restructure) to reorganize and add fields to the polyline shapefile's attribute table. The length field ('Length_km') was also added and then populated using 'Calculate Geometry' (Property = Length, Use coordinate system of the data frame = WGS 1984 UTM Zone 18N, Unit = Kilometers), which can be accessed by right clicking on the attribute field name in the table view.
Process_Date: 2014
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Seth Ackerman
Contact_Organization: U.S. Geological Survey
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
Country: USA
Contact_Voice_Telephone: 508) 548-8700 x2315
Contact_TDD/TTY_Telephone: sackerman@usgs.gov
Contact_Facsimile_Telephone: (508) 457-2310
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: 20170418
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
