Any spurious data points were removed during processing. Duplicate names may exist for the linename attribute; however further querying the data by the "Survey", "Device", or "JD" attributes will distinguish a unique trackline for each record in this spatial dataset.
Only the subsets of interferometric bathymetric sonar collected during field activities 06012 and 07001 that are within the study area in the northern Cape Cod Bay survey area south of Brant Rock, Massachusetts and have been included in this spatial dataset.
This shapefile includes all bathymetric tracklines collected in the northern Cape Cod Bay survey area, however, not all of these tracklines were included in the final bathymetric grid published in this same report. Data collected along transit lines, east-west seismic tie lines, and other lines of poor quality were excluded from this grid. The " Mosaic" attribute in this shapefile identifies the 528 lines that were included and the 60 lines that were not included in the final grid.
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Field activity 06012: The SWATHplus transducers were mounted on a rigid pole, approximately 2.6 m below the water line, along the starboard side of the R/V Megan T. Miller. Position data were provided by an Ashtech Z-Surveyor Extreme for real-time kinematic (RTK) navigation (an Ashtech BR2G Differential Global Positioning System (DGPS) was used as a backup navigation system) and recorded to the raw data files (SXR) via Swath Processor (version 2.07) acquisition software. During some portions of the survey, technical difficulties caused the GPS systems to malfunction and lose the "fixed" RTK signal. When this occurred, the navigation system defaulted to a "float" RTK, and then to a GPS (stand alone) signal, after which the navigation signal was lost completely. Surveying was halted until a reliable GPS signal was restored. A conservative estimate of positional accuracy is +/- 2 meters, but when the navigation system was providing the "fixed" RTK signal, positional accuracy is <1 m.
Field activities 07001, 07002, and 08002: The SWATHplus transducers were mounted on a rigid pole from the bow of the R/V Rafael, approximately 0.5 m below the water line during surveys 07001 and 08001, and 2.6 m below the water line on the starboard side for survey 07002. Position data were recorded by Hypack software to Hypack raw files using an Ashtech Z-Surveyor Extreme for real-time kinematic (RTK) navigation, and an Ashtech BR2G for Differential Global Positioning System (DGPS) navigation. DGPS navigation from the primary F180 antenna was recorded to the raw sonar data files (SXR) via SWATHplus acquisition software. A conservative estimate of positional accuracy is +/- 2 meters.
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report:
Based on SWATHplus interferometric sonar system specifications, vertical accuracy of the raw data may approximate 1% of water depth, which translates to 0.1 0.6 meters within the northern Cape Cod Bay survey area. RTK-GPS was used to establish water-level heights relative to Mean Lower Low Water (MLLW), providing decimeter-scale accuracies. Tide-correction was done in post-processing (see process steps). Refraction artifacts were minimized by acquiring a range of sound velocity profiles throughout the survey area to model the sound velocity structure of the water column. Changes in vessel draft due to fuel and water usage were not considered.
Source_Information:
Source_Citation:
Citation_Information:
Originator:
Information unavailable from original metadata. Assumed to be USGS.
Publication_Date: unknown
Title: Information unavailable from original metadata.
Other_Citation_Details:
This file had a source contribution, but no other source information. This information had to be modified to meet the standard.
Type_of_Source_Media: Information unavailable from original metadata.
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20060816
Ending_Date: 20080507
Source_Currentness_Reference:
Information unavailable from original metadata, but assumed to be the same as the time period of content. Ground condition of four separate date ranges - 20060816 to 20060823; 20070429 to 20070503; 20070725 to 20070807; 20080429 to 20080507.
Source_Citation_Abbreviation: Information unavailable from original metadata.
Source_Contribution:
Sonar Configuration: Bathymetry data were acquired using a Systems Engineering and Assessment Ltd. (SEA) SWATHplus interferometric sonar operating at 234 kHz (06012, 07001, 08002) or 117 kHz (07002). Survey lines were run at an average speed of 5 knots and were spaced 75-200 m apart to obtain overlapping swaths of data and full coverage of the seafloor. During USGS field activities 06012 and 07002, the SWATHplus transducers were mounted on a rigid pole on the starboard side of the R/V Megan Miller, about 2.6 m below the waterline.
During 06012, a TSS DMS 2-05 motion reference unit was mounted directly above the sonar transducers and continuously recorded and sent vertical displacement (heave) and attitude (pitch and roll) of the vessel during acquisition to the SWATHplus software. During 06012 vessel heading was determined by a KVH compass that was corrected for magnetic variation of +15.583 degrees (from NOAA Chart number13246 36th ed., Mar. 10/01) during post processing. During 07002, a Coda Octopus F180 inertial-motion unit, mounted directly above the transducers, measured true heading, vertical displacement (heave) and attitude (pitch and roll) of the vessel during acquisition.
Field activities 07001 and 08002: the SWATHplus transducers were mounted on a rigid pole on the bow of the R/V Rafael, about 0.5 m below the waterline. A Coda Octopus F180 inertial-motion unit, mounted directly above the transducers, measured true heading, vertical displacement (heave) and attitude (pitch and roll) of the vessel during acquisition.
Navigation:
Field activity 06012: Real-Time Kinematic (RTK) GPS navigation was used to determine the horizontal and vertical position (xyz) of the GPS antenna mounted directly above the SWATHplus transducers with sub-meter accuracy. The RTK-corrected coordinates were transmitted to the ship from a land-based RTK-GPS station established by the USGS at NOAA Tidal Station #8446009 in Brant Rock Harbor, MA.
Field activities 07001, 07002, and 08002: Differential GPS (DGPS) navigation was used to determine the horizontal position (x,y) of the GPS antenna mounted directly above and forward (F180R primary antenna, 0.5 meters) of the SWATHplus transducers with +/- 1-2 meter accuracy. RTK-GPS was used to determine the vertical position of the Ashtech GPS antenna (z) with sub-meter accuracy.
Vertical coordinates for all four surveys were referenced to Mean Lower Low Water (MLLW) using the offset between the North American Vertical Datum of 1988 (NAVD 88) and MLLW published for the tidal benchmark. Horizontal (x and y) and vertical (z) offsets between the transducers, motion sensor, and GPS antenna were precisely measured and recorded within the SWATHplus acquisition software (SEA Swath Processor (2005)), which established the motion sensor as the common reference point during data acquisition.
Speed of Sound:
Sound-velocity profiles were collected approximately every 2 hours by a hand-casted Applied MicroSystems SV Plus sound velocimeter. The depth of the transducers below the sea surface was measured and recorded within the SWATHplus acquisition software, and used as a reference point for deriving the acoustic ray path based on sound velocity profiles.
Tides: During post-processing, soundings were referenced to local MLLW by using orthometric to chart datum offsets obtained from NOAA Tidal Station #8446009 at Brant Rock Harbor, Massachusetts. Data were processed and gridded by using the SEA SWATHplus Swath Processor (version 10.0) CARIS Hydrographic Information Processing System (HIPS version 6.1).
Process_Step:
Process_Description:
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. 3.05.19.0). Processing occurred in 2006, 2007, and 2008.
Process_Date: 2008
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Brian Andrews
Contact_Organization: U.S. Geological Survey
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: USA
Contact_Voice_Telephone: 508-548-8700 x2348
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: bandrews@usgs.gov
Process_Step:
Process_Description:
CARIS Processing: A new Computer Aided Resource Information System (CARIS) Hydrographic Information Processing System (HIPS) project (ver. 6.1) was created with projection information set to Universal Transverse Mercator (UTM) Zone 19, 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: 2008
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Brian Andrews
Contact_Organization: U.S. Geological Survey
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: USA
Contact_Voice_Telephone: 508-548-8700 x2348
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: bandrews@usgs.gov
Process_Step:
Process_Description:
A series of Perl and AWK 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_nav2.pl (which runs the CARIS program printfnav for all the lines in the HDCS dir) and the grep statement below. (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) > grep Accepted combined.txt > greped_combined.txt.
B. The files extracted from CARIS HIPS have 4-5 navigation fixes per second. Each file was subsampled to 1 fix per second by using AWK (see code below) to remove the fractions-of-a-second from the time column then grabbing the first occurrence of each second. > awk '{print $1" "substr($2,1,8)" "$3" "$4" "$5}' greped_combined.txt | awk '$2 != prev { print; prev = $2 }' > 2.CCB_NAV_awked.txt
C. Checked that there were no additional spurious fixes outside the survey area using another series of AWK code (see code below), and reformatted for conversion from comma separated value (CSV) data to ESRI point feature class > awk -F" " '{if(substr($4,1,3)=="-70") print $0}' 2.* | awk -F" "
'{if(substr($3,1,1)=="4") print $0}'| awk -f reformat_CARIS2Arc_CCB.awk >
CCB_bathyNAV_all.csv
Process_Date: 201001
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:
In ArcCatalog (version 9.3), navigation text (CCB_bathyNav_all.csv) 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). {output file: XYCCB_bathyNAV_all.shp]
Process_Date: 201001
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: 2.1 FeatConv - Points to Line v2; USGS in-house software) was then used within ArcMap (version 9.3) to convert the navigation points (XYCCB_bathyNAV_all.shp) to a temporary trackline shapefile (CCB_bathyNAV_all_trk.shp). The trackline shapefile was checked to ensure no spurious fixes. XTools Pro (version 5.3.0) for ArcGIS desktop was used to reorganize and add fields to the polyline shapefile's attribute table. Fields for device used to collect the data ('DEVICE'), survey vessel name ('Vessel'), and year ('YEAR') were added and populated using the table editor in ArcMap (version 9.3). Table attributes for the survey ("SURVEY') and Julian day ('JD') of data collection, were already populated but edited to be consistent with the other trackline shapefile in this report. The length field ('LENGTH_KM') was populated using 'Calculate Geometry' (Property=Length; Use coordinate system of the data frame=WGS 1984 UTM Zone 19N; Unit=Kilometers), which can be accessed by right-clicking on the attribute field name in the table view. (output file: CCB_BathTracklines.shp)
Process_Date: 201001
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Brian Andrews
Contact_Organization: U.S. Geological Survey
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: USA
Contact_Voice_Telephone: 508-548-8700 x2348
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: bandrews@usgs.gov
Process_Step:
Process_Description:
Edits to the metadata were made to fix any errors that MP v 2.9.30 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 format of the time period of content and some process dates had to be fixed. This file had a source contribution, but no other source information. This information had to be modified to meet the standard. 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: 20151120
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
Address: 384 Woods Hole Rd.
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
