This grid represents interpolated data; processed to account for gaps that occurred along-track and between adjacent lines.
All quality main survey line bathymetric data (generally shore parallel) that were collected within the Duxbury to Hull survey area were incorporated in the grid that this hillshade was derived from. Approximately 125 square-km of additional bathymetric data were collected south of Brant Rock, Massachusetts during these field activities will be published in a subsequent data release focused on Cape Cod Bay. Soundings were processed and edited using Computer Aided Resource Information System (CARIS) Hydrographic Information Processing System (HIPS; ver. 6.1). Although the soundings were manually edited, small data spikes may exist at outer edges of some swaths. In addition, small gaps between adjacent survey lines may exist in depth less than 14 meters. Tielines (generally shore perpendicular) were not used in grid generation but used to verify tide corrections during post-processing.
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Hydrographic survey H10993: Horizontal sounding positional control for the NOAA H10993 survey was determined using the Global Positioning System (GPS) corrected by U.S. Coast Guard Differential GPS (DGPS) beacon stations. The primary and only DGPS beacon used for survey H10993 was Portsmouth Harbor, NH (Beacon No. 771). No horizontal control stations were established for the NOAA survey. Additional information may be found in the NOAA Descriptive Report for survey H10993, the Data Acquisition and Processing Report, and the Horizontal and Vertical Control 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 the Z-Surveyor Extreme for real-time kinematic (RTK) navigation (the Ashtech BR2G DGPS was used as a backup navigation system) and recorded to the raw data files (SXR) via SWATHPlus (version 2.07) on the acquisition computer. During some portions of the survey, technical difficulties caused the GPS systems to malfunction; in some instances the acquisition systems fell back on the DGPS navigation; but in some cases surveying was halted until a reliable GPS signal could be achieved. A conservative estimate of positional accuracy is estimated to be 10 m although when the system was recording RTK navigation the positional accuracy may be <1 m as RTK-GPS provides horizontal positional accuracies on the decimeter scale (
http://www.noaa.gov;
http://www.nos.noaa.gov;
http://www.ngs.noaa.gov). Field activity 07001: The SWATHPlus transducers were mounted on a rigid pole, approximately 0.5 m below the water line, from the bow of the of the R/V Rafael of Woods Hole, MA. Position data were provided by the Ashtech Extreme for real-time kinematic (RTK) navigation (the Ashtech BR2G Differential Global Positioning System (DGPS) was used as a backup navigation system) and recorded to the raw data files (SXR) via SWATHPlus (version 3.X) on the acquisition computer. A conservative estimate of positional accuracy is estimated to be 10 m although when the system was recording RTK navigation the positional accuracy may be <1 m as RTK-GPS provides horizontal positional accuracies on the decimeter scale (
http://www.noaa.gov;
http://www.nos.noaa.gov;
http://www.ngs.noaa.gov).
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report:
NOAA Hydrographic survey H10993: NOAA's National Ocean Service Hydrographic Surveys Specifications and Deliverables closely follow the International Hydrographic Organization’s Standards for Hydrographic Surveys, Special Publication 44, Fifth Edition, February 2008, specifically for Order 1 surveys. Positioning and attitude on Launch 1005 were determined with a TSS POS/MV 320 (version 2) GPS aided inertial navigation system. Positioning and attitudes on Launch 1014 were determined with a TSS POS/MV 320 (version 3) GPS-aided inertial navigation system. Launch 1014 also used a Digibar Pro to measure surface sound velocity and achieve continuous refraction correctors at the transducer. The tidal datum for survey H10993 is Mean Lower Low Water (MLLW). The operating tide station at Boston, MA(844-3970) served as control for datum determination. Observed tide files were e-mailed by Tidbit daily during acquisition and applied to all sounding data using preliminary zoning. Final zoning was received and applied with observed water levels. The verified water level data was received and was compared to the observed data. No difference between these verified and observed water level data were notice. Verified tides using final tide zoning were re-applied by NOAA's Atlantic Hydrographic Branch during post-processing. Refer to the Fall Data Acquisition and Processing Report (DAPR) and the Horizontal and Vertical Control Report, for detailed equipment, vessel configuration and setting information. USGS field activities 06012 and 07001: Vertical accuracy of the raw data based on system specifications may approximate 1% of water depth, 0.1-0.4 meters within the survey area. However, overall vertical accuracies on the order of 0.5 m or more are assumed based on the following considerations. In 2006, ship motion was recorded with a TSS DMS 2-05, used to correct for vessel roll, pitch, heave, and yaw. In 2007, the Octopus F180 Attitude and Positioning system was used to correct ship motion. 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: U.S. Geological Survey
Publication_Date: unpublished material
Title: Information unavailable from original metadata.
Other_Citation_Details:
The source information was incomplete and had to be modified to meet the standard.
Type_of_Source_Media: disc
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20030820
Ending_Date: 20070502
Source_Currentness_Reference:
ground condition of three separate time periods - 20030820 to 20031003; 20060804 to 20060820; 20070422 to 20070502
Source_Citation_Abbreviation: Information unavailable from original metadata.
Source_Contribution:
For USGS field activities 06102 and 07001: Bathymetry data were acquired with a Systems Engineering and Assessment Ltd. (SEA) SWATHPlus 234 kHz interferometric sonar. Survey lines were run at an average speed of 5 knots and were spaced 100 m apart to obtain overlapping swaths of data and full coverage of the seafloor. During USGS field activity 06012, the transducers were mounted on a rigid pole on the starboard side of the RV Megan Miller, about 2.6 m below the waterline. A TSS DMS 2-05 motion reference unit was mounted directly above the sonar transducers and continuously recorded vessel position and attitude data. Heading was determined using an Ashtech ADU2 for lines l1f1-l99f1, and a KVH compass (with processor calculated declination +15.583 to be applied during post-processing) for lines l99f2-end of survey. During USGS field activity 07001, the transducers were mounted on a rigid pole on the bow of the RV Rafael, about 0.5 m below the waterline. A CodaOctopus F-180 inertial-motion unit, mounted directly above the transducers, measured vertical displacement (heave) and attitude (pitch and roll) of the vessel during acquisition. Navigation was based on a Real-Time Kinematic Global Positioning System (RTK-GPS); the RTK-GPS antenna was mounted directly above the interferometric sonar head. The RTK-corrected GPS signal was sent to the ship from a base station established by the USGS on land. Horizontal (x and y) and vertical (z) offsets between the transducers and motion sensor and antenna and motion sensor were precisely measured and recorded within the SWATHPlus acquisition software (SEA Swath Processor (2005)). These offsets are used to establish the motion sensor as the common reference point for data acquisition. Additionally, the depth of the transducers below the water surface was measured and recorded within the SEA Swath Processor acquisition software. This depth was used to derive the speed of sound profile and acoustic ray path based on speed of sound profiles collected within the survey area. Sound-velocity profiles were collected approximately every 2 hours by a hand-casted Applied MicroSystems SV Plus sound velocimeter. 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). For NOAA Hydrographic survey H10993: Launch 1005 acquired multibeam-echosounder data using a hull-mounted RESON SeaBat 8101 multibeam system. All positioning and attitude on Launch 1005 were determined with a TSS POS/MV 320 (version 2) GPS aided inertial navigation system. Launch 1014 acquired multibeam-echosounder data using a RESON SeaBat 8125 multibeam system. For continuous refraction correctors at the transducer, a Digibar Pro was used for the surface sound velocity and all positioning and attitudes on Launch 1014 were determined with a TSS POS/MV 320 (version 3) GPS-aided inertial navigation system. The RESON SeaBat 8101 is a 1.5 degree beam angle system which operates at a frequency of 240 kHz and collects 101 individual soundings in a swath oriented perpendicular to the vessel track. The RESON SeaBat 8125 is a 0.5 degree beam angle system which operates at a frequency of 455 kHz and collects 240 individual soundings in a swath oriented perpendicular to the vessel track. Sounding positional control was determined using the Global Positioning System (GPS) corrected by U.S. Coast Guard Differential GPS (DGPS) beacon stations. The primary and only DGPS beacon used for this survey was Portsmouth Harbor, NH (Beacon # 771). No horizontal control stations were established for this survey. All bathymetry processing, including tide-correction (based on final zone tidal models), were done by NOAA Hydrographers. NOAA's Computer Aided Resource Information System (CARIS) directory was provided to the USGS. Refer to the Fall Data Acquisition and Processing Report (DAPR) and the Horizontal and Vertical Control Report, for detailed equipment, vessel configuration and setting information.
Process_Step:
Process_Description:
Prepare tide correction data for field activity 06012 and 07001: Depths were corrected to Mean Lower Low Water (MLLW) using 1 second RTK-GPS heights of the GPS receiver mounted over the SWATHPlus sonar head. These heights were extracted from each HYPACK navigation file using the AWK script "doRTK1_by_line_FIX" and smoothed in MATLAB (version 7.20.232 R2006a) using a third order polynomial. The smoothed 1 second heights were averaged to 1 minute heights and formatted for input to Swath Processor using the AWK script "DoRTK2". The resulting ASCII text file was then reformatted to comply with the format (HH:MM DD/MM/YYYY TTTTT.TTT) needed in the tide table in the SEA Swath Processor session file (sxs). During the next step the tide data is merged into the bathymetric soundings data during the conversion of SWATHPlus raw (sxr) files to SWATHPlus processed (sxp) files. Processing occurred in 2006, 2007, and 2008.
Process_Date: 2008
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:
Raw to Processed conversion for USGS field activity 06012 and 07001: 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). During the conversion process, sound velocity profiles were used to minimize potential refraction artifacts from fluctuations in the speed of sound within the water column. Various bathymetric filters were applied to eliminate sounding outliers. During this conversion process the tidal information from the previous process step was merged into the new processed file (sxp). The filters in Swath Processor greatly reduced the appearance of an artifact observed in the port side of the bathymetric data from survey 06012; probably the result of a multi-pathing sound wave off the hull of the survey vessel. Although minimized, this artifact may still give the final bathymetry grid a stripy appearance, especially in areas of little local relief.
Process_Date: 2008
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:
CARIS processing for USGS field activity 06012 and 07001: A new CARIS HIPS project (ver. 6.1) was created with for each field activity 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. A 5 meter resolution Bathymetric and Statistical Error (BASE) Surface was created from the files for each Julian day. The BASE surface for each day was reviewed for any inconsistencies or data anomalies. Navigation was edited as needed using the navigation editor tool in CARIS. Filters were applied to each line including beam to beam slopes and across track angle. The CARIS refraction editor was used to adjust the speed of sound in cases where the velocimeter did not provide adequate correction to flatten out the depth profiles produced by localized variations in speed of sound through the water column. CARIS processing for NOAA hydrographic survey H10993: The CARIS HIPS directory was received from the National Oceanic and Atmospheric Administration - National Geophysical Data Center (NOAA-NGDC). The multibeam bathymetric data from NOAA was delivered fully processed and tide-corrected by NOAA Hydrographers. The CARIS HIPS project was reviewed and checked for any inconsistencies. Survey lines outside of the Duxbury to Hull survey area were removed from the project. Processing occurred in 2008 and 2009.
Process_Date: 2009
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:
BASE surface creation for USGS field activity 06012 and 07001: A new CARIS HIPS project was made to create final BASE surfaces for all of the bathymetric data from the NOAA and USGS surveys. A 5 meter BASE surface was created for the entire area of the Duxbury to Hull survey area utilizing all the quality bathymetric soundings data from USGS surveys 06012 and 07001. This surface demonstrates the data gaps especially those resulting from navigation problems during survey 06012 and gaps between survey lines in shallow water during survey 07001. Another 10 meter BASE surface (with 4 iterations of interpolation) was created from the same data from survey 06012 and 07001 in order to fill the data gaps (these two grids will be merged using a technique that preserves the higher-resolution data - see next process step).
BASE surface creation for NOAA hydrographic survey H10993: A 5 meter BASE surface (with 1 iteration of interpolation) was created for the NOAA hydrographic data using all quality bathymetric soundings data within the Duxbury to Hull survey area.
Process_Date: 20090624
Source_Produced_Citation_Abbreviation:
CARIS HIPS BASE surfaces (June24_5m.hns, June24_10m_Interp4.hns, H10993_5m_Interp.hns)
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:
The CARIS HIPS BASE surfaces for the USGS 5 meter grid, USGS 10 meter grid, and NOAA 5 meter grid (June24_5m.hns, June24_10m_Interp4.hns, and H10993_5m_Interp.hns respectively) were converted to IVS Fledermaus Digital Terrain Models (DTM) using Interactive Visualization Systems (IVS 3D) Data Magician (DMagic, version 6.7); [Import Gridded Data - from CARIS BASE surface]. Three DTM files with the same filenames were created. The USGS 5 meter and 10 meter grids were combined using IVS 3D Fledermaus Commander (FMCommand) and the tool "dtmmerge" (highres setting preserves the higher-resolution data and fills the gaps with data from the lower resolution DTM; outputfile: 5 meter grid usgs_combined_temp.dtm). The resulting DTM was then combined with the 5 meter NOAA DTM using the same method (outputfile: June24_ALL_new.dtm). In IVS 3D DMagic, the grid June24_ALL_new.dtm was exported to ARC/INFO ASCII GRID format (outputfile: June24_ALL_new.asc).
Process_Date: 20090624
Source_Produced_Citation_Abbreviation:
IVS 3D Digital Terrain Models (DTM; usgs_combined_temp.dtm, June24_ALL_new.dtm)
Source_Produced_Citation_Abbreviation: ARC/INFO ASCII GRID (June24_ALL_new.asc)
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:
Using ESRI ArcToolbox (version 9.3), converted ARC/INFO ASCII GRID to a temporary ESRI ArcRaster Grid [Conversion Tools, To Raster, ASCIIToRaster]. Removed the NODATA value of zero using ArcToolbox output to a temporary grid [Spatial Analyst Tools, Extraction, ExtractByAttributes - VALUE < 0]. Clipped the temporary grid by a boundary polygon shapefile for the Duxbury to Hull survey area using ArcToolbox creating final interpolated bathymetry grid "DH_bathy5m" [Spatial Analyst Tools, Extraction, ExtractByMask].
Process_Date: 20090624
Source_Produced_Citation_Abbreviation: ESRI ArcRaster Grid (DH_bathy5m)
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:
Using the Spatial Analyst extension in ESRI ArcMap (version 9.3), Surface Analysis - Hillshade with an azimuth of 335 and an altitude of 30; Z-factor of 3; and cell size 5 meters.
Source_Used_Citation_Abbreviation: ESRI ArcRaster Grid (DH_hathy5m)
Process_Date: 20090624
Source_Produced_Citation_Abbreviation: ESRI ArcRaster Grid (DH_hlshd5m)
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:
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. The source information was incomplete and had to be modified to meet the standard. The format of the time period of content had to be fixed. The distribution format was modified in an attempt to be more consistent with other metadata files of the same data format. Other minor edits were probably performed (title, publisher, publication place, etc.). 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: 20151110
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
