All navigation from seismic reflection data collected during cruise ACAD07007 was used to generate this shapefile.
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
The SB-0512i was towed approximately 6 m astern and approximately 1.5 m below the sea surface. DGPS navigation (assumed to be accurate within 1-2 m) was obtained from the receiver mounted above the interferometric sonar head, but towfish layback was not accounted for. The layback of the towfish adds additional uncertainty due to changes in angle and scope of the tow cable in response to sea state and vessel speed. The use of J-Star acquisition software during the ACAD07007 cruise caused a reduction in the resolution of navigation values recorded to the trace headers from the onboard DGPS. During acquisition, J-Star truncates the three least significant digits from the raw navigation string, which reduces the resolution of each navigation fix on the order of 1-2 meters. Due to this acquisition flaw, the ship-track polylines in this shapefile display a "sawtooth" pattern when viewed at scales finer than approximately 1:3000. Based on horizontal offsets between the fish and GPS receiver, fish motion behind the vessel, and error associated with the acquisition system, the resulting positional accuracy is assumed to be +/- 20 m.
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: Unpublished material
Title: Seismic data collection
Type_of_Source_Media: disc
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20070610
Ending_Date: 20070622
Source_Currentness_Reference: ground condition
Source_Citation_Abbreviation: raw seismic data
Source_Contribution:
Trackline acquisition at sea (2007):
Chirp seismic data were collected using an EdgeTech Geo-Star FSSB sub-bottom profiling system and an SB-0512i towfish (0.5-12 kHz) on the R/V Acadiana of Loreauville, LA. EdgeTech J-Star acquisition software was used to control the Geo-Star topside unit and digitally log trace data in the EdgeTech JSF format. Data were acquired using a 0.25-s fire rate, a 5-ms pulse length, and a 0.5 to 8 kHz sweep (swept frequency). Tracklines are spaced 100 to 125 m apart in the shore parallel direction and about 1 km apart in the shore perpendicular direction.
Process_Step:
Process_Description:
jsftosegy (no version), a C script developed by Tom O'Brien (USGS - Woods Hole Seafloor Mapping Group) was used to convert raw chirp traces in the JSF format to chirp-processed, envelope traces in the SEG-Y rev. 1 standard format.
Process_Date: 2007
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Wayne E. Baldwin
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) 548-8700x2226
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: wbaldwin@usgs.gov
Process_Step:
Process_Description:
A script was run that used Seismic Unix (version 4.1) to read the SEG-Y files, write a Seismic Unix file, and extract SEG-Y trace header information, which included shot number, longitude, latitude, year, day, and time of day. Geographic coordinates were converted to UTM zone 16 coordinates using PROJ (version 4.6.0). Before saving the header information to a text file, the data were filtered using AWK to save only unique shot point locations. In addition, a separate text file containing even 500 shot intervals was saved. The 500 shot text file maintains the start and end shots, which may not necessarily by unique fixes. A 500 shot interval was chosen because it corresponds to the annotaion interval provided along the top of the seismic-reflection profile JPEG images, which are included in the "Seisimage" folder of the "GIS_Catalog".
Process_Date: 2007
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Wayne E. Baldwin
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) 548-8700x2226
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: wbaldwin@usgs.gov
Process_Step:
Process_Description:
Text files for each seismic line were concatenated into two comma-delimited text files, one containing unique shot point positions ('seismic_shtunique_07007.csv', which is provided in the zip-compressed package of the shapefile 'seismic_sht_07007.shp')
, and another containing the 500 shot intervals.
Process_Date: 2007
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Wayne E. Baldwin
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) 548-8700x2226
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: wbaldwin@usgs.gov
Process_Step:
Process_Description:
Both concatenated, comma-delimited text files were imported into ArcMap (version 9.2) and saved as points in the ESRI shapefile format.
Process_Date: 2007
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Wayne E. Baldwin
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) 548-8700x2226
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: wbaldwin@usgs.gov
Process_Step:
Process_Description:
The point shapefile containing unique shot point positions was used as an input for a VACExtras (version 1.9.4), 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 shot number field was used to define the point order. The length of each line segment was calculated and inluded in a new attribute field using Xtools Pro for ArcGIS desktop (version 4.1.0), specifying UTM Zone 16 N - kilometers.
Process_Date: 2007
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Wayne E. Baldwin
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) 548-8700x2226
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: wbaldwin@usgs.gov
Process_Step:
Process_Description:
Edits to the metadata were made to fix any errors that MP v 2.9.34 flagged. This is necessary to enable the metadata to be successfully harvested for various data catalogs. In some cases, this meant adding text "Information unavailable" or "Information unavailable from original metadata" for those required fields that were left blank. Other minor edits were probably performed (title, publisher, publication place, etc.). The source information was incomplete and had to be modified to meet the standard. Formatting of the cross-references was fixed to meet the metadata standard. Minor fixes to the attribute format for some attributes were needed. The distribution format name was modified in an attempt to be more consistent with other metadata files of the same data format. The metadata date (but not the metadata creator) was edited to reflect the date of these changes. The metadata available from a harvester may supersede metadata bundled within a download file. Compare the metadata dates to determine which metadata file is most recent.
Process_Date: 20161103
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
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: Crossref DOI link was added as the first link in the metadata.
Process_Date: 20191118
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
