ASCII grid of bathymetry data collected by the U.S. Geological Survey and the National Oceanic and Atmospheric Administration offshore of Massachusetts between Duxbury and Hull with data gaps (DH_bathy_wgaps.asc, ARC/INFO ASCII GRID, UTM Zone 19, WGS84)

Metadata also available as - [Outline] - [Parseable text] - [XML]

Frequently anticipated questions:

What does this data set describe?

Title:
ASCII grid of bathymetry data collected by the U.S. Geological Survey and the National Oceanic and Atmospheric Administration offshore of Massachusetts between Duxbury and Hull with data gaps (DH_bathy_wgaps.asc, ARC/INFO ASCII GRID, UTM Zone 19, WGS84)
Abstract:
These data were collected under a cooperative agreement with the Massachusetts Office of Coastal Zone Management (CZM) and the U.S. Geological Survey (USGS), Coastal and Marine Geology Program, Woods Hole Science Center (WHSC). Initiated in 2003, the primary objective of this program is to develop regional geologic framework information for the management of coastal and marine resources. Accurate data and maps of sea-floor geology are important first steps toward protecting fish habitat, delineating marine resources, and assessing environmental changes due to natural or human impacts. The project is focused on the inshore waters (5-30 m deep) of Massachusetts between the New Hampshire border and Cape Cod Bay. Data collected for the mapping cooperative have been released in a series of USGS Open-File Reports (http://woodshole.er.usgs.gov/project-pages/coastal_mass/html/current_map.html). This spatial dataset is from the study area located between Duxbury and Hull Massachusetts, and consists of high-resolution geophysics (bathymetry, backscatter intensity, and seismic reflection) and ground validation (sediment samples, video tracklines and bottom photographs). The data were collected during four separate surveys conducted between 2003 and 2007 (NOAA survey H10993 in 2003, USGS-WHSC survey 06012 in 2006, and USGS-WHSC surveys 07001 and 07003 in 2007) and cover more than 200 square kilometers of the inner continental shelf.
  1. How might this data set be cited?
    U.S. Geological Survey, 2010, ASCII grid of bathymetry data collected by the U.S. Geological Survey and the National Oceanic and Atmospheric Administration offshore of Massachusetts between Duxbury and Hull with data gaps (DH_bathy_wgaps.asc, ARC/INFO ASCII GRID, UTM Zone 19, WGS84): Open-File Report 2009-1072, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts.

    Online Links:

    This is part of the following larger work.

    Barnhardt, Walter A., Ackerman, Seth D., Andrews, Brian D., and Baldwin, Wayne E., 2010, Geophysical and Sampling Data from the Inner Continental Shelf: Duxbury to Hull, Massachusetts.: Open-File Report 2009-1072, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -70.829915
    East_Bounding_Coordinate: -70.596158
    North_Bounding_Coordinate: 42.346323
    South_Bounding_Coordinate: 42.077031
  3. What does it look like?
    http://pubs.usgs.gov/of/2009/1072/GIS/browse_jpg/big/DH_bathy_wgaps.jpg (JPEG)
    ASCII grid of bathymetry
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 20-Aug-2003
    Ending_Date: 02-May-2007
    Currentness_Reference:
    ground condition of three separate time periods - 20030820 to 20031003; 20060804 to 20060820; 20070422 to 20070502
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: raster digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Raster data set. It contains the following raster data types:
      • Dimensions 6052 x 3761 x 1, type Pixel
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 19
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -69.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000
      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 5.001330
      Ordinates (y-coordinates) are specified to the nearest 5.001330
      Planar coordinates are specified in meters
      The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257224.
  7. How does the data set describe geographic features?

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • U.S. Geological Survey
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?

Why was the data set created?

This grid represents approximately 200 square kilometer of bathymetric data that were collected in 2003, 2006 and 2007. This is a merged grid of interferometric (Systems Engineering and Assessment Ltd. SWATHPlus-M) and multibeam (RESON SeaBat 8101 and 8125) bathymetric sonar data that were collected by the U.S. Geological Survey and the National Oceanic and Atmospheric Administration, respectively, during three surveys (NOAA survey H10993 and USGS surveys 06012 and 07001) offshore of Massachusetts, between Duxbury and Hull. These data are used to define the sea-floor morphology as part of the Massachusetts Sea-floor Mapping Project. This grid shows the extent of data collected along each swath with no interpolation, therefore it demonstrates the data gaps where adjacent swaths did not meet and where gaps exist because the bathymetric data along a particular track were deemed usable in the final grid.

How was the data set created?

  1. From what previous works were the data drawn?
    Information unavailable from original metadata. (source 1 of 1)
    U.S. Geological Survey, unpublished material, 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_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 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.
  2. How were the data generated, processed, and modified?
    Date: 2008 (process 1 of 10)
    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. Person who carried out this activity:
    Seth Ackerman
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2315 (voice)
    508-457-2310 (FAX)
    sackerman@usgs.gov
    Date: 2008 (process 2 of 10)
    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. Person who carried out this activity:
    Seth Ackerman
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2315 (voice)
    508-457-2310 (FAX)
    sackerman@usgs.gov
    Date: 2009 (process 3 of 10)
    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 some cases 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 took place in 2008 and 2009. Person who carried out this activity:
    Seth Ackerman
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2315 (voice)
    508-457-2310 (FAX)
    sackerman@usgs.gov
    Date: 24-Jun-2009 (process 4 of 10)
    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 (see note in completeness report) and gaps between survey lines in shallow water during survey 07001. BASE surface creation for NOAA hydrographic survey H10993: A 5 meter BASE surface was created for the NOAA hydrographic data using all quality bathymetric soundings data within the Duxbury to Hull survey area. Person who carried out this activity:
    Seth Ackerman
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2315 (voice)
    508-457-2310 (FAX)
    sackerman@usgs.gov
    Data sources produced in this process:
    • CARIS HIPS BASE surfaces (June24_5m.hns, H10993_5m.hns)
    Date: 24-Jun-2009 (process 5 of 10)
    The CARIS HIPS BASE surfaces for the USGS 5 meter grid and NOAA 5 meter grid (June24_5m.hns, H10993_5m.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]. Two DTM files with the same filenames were created. The USGS 5 meter and the 5 meter NOAA dtm were combined using IVS 3D Fledermaus Commander (FMCommand) and the tool "dtmmerge" (outputfile: June24_ALL_gaps.dtm). The floating-point grid was exported to ARC/INFO ASCII GRID format (outputfile: June24_ALL_gaps.asc). Person who carried out this activity:
    Seth Ackerman
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2315 (voice)
    508-457-2310 (FAX)
    sackerman@usgs.gov
    Data sources produced in this process:
    • IVS 3D Digital Terrain Model (DTM; June24_ALL_gaps.dtm)
    • ARC/INFO ASCII GRID (June24_ALL_gaps.asc)
    Date: 08-Jul-2009 (process 6 of 10)
    The ARC/INFO ASCII GRID format was renamed from June24_ALL_gaps.asc to DH_bathyhlshd_wgaps.asc Person who carried out this activity:
    Seth Ackerman
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2315 (voice)
    508-457-2310 (FAX)
    sackerman@usgs.gov
    Data sources produced in this process:
    • ARC/INFO ASCII GRID (DH_bathyhlshd_wgaps.asc)
    Date: 10-Nov-2015 (process 7 of 10)
    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. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 20-Jul-2018 (process 8 of 10)
    USGS Thesaurus keywords added to the keyword section. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 18-Nov-2019 (process 9 of 10)
    Crossref DOI link was added as the first link in the metadata. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 08-Sep-2020 (process 10 of 10)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
  3. What similar or related data should the user be aware of?
    Barnhardt, Walter A., Andrews, Brian D., and Butman, Bradford, 2006, High-Resolution Mapping of the Inner Continental Shelf: Nahant to Gloucester, Massachusetts: Open-File Report 2005-1293, U.S. Geological Survey, Reston, VA.

    Online Links:

    Ackerman, Seth D., Butman, Bradford, Barnhardt, Walter A., Danforth, William W., and Crocker, James M., 2006, High-Resolution Geologic Mapping of the Inner Continental Shelf: Boston Harbor and Approaches, Massachusetts: Open-File Report 2006-1008, U.S. Geological Survey, Reston, VA.

    Online Links:

    Barnhardt, Walter A., Andrews, Brian D., Ackerman, Seth D., Baldwin, Wayne E., and Hein, Christopher J., 2009, High-Resolution Geological Mapping of the Inner Continental Shelf: Cape Ann to Salisbury Beach, Massachusetts: Open-File Report 2007-1373, U.S. Geological Survey, Reston, VA.

    Online Links:

    National Oceanic and Atmospheric Administration, 2003, Data Acquisition and Process Report - NOAA Ship Thomas Jefferson (August - November 2003): Data Acquisition and Process Report (DAPR) NOAA Ship Thomas Jefferson (August - November 2003), National Oceanic and Atmospheric Administration, National Geophysical Data Center (NGDC), National Geophysical Data Center, Boulder, CO.

    Online Links:

    NOAA (National Oceanic and Atmospheric Administration), 2003, Descriptive Report, Basic Hydrographic Survey H10993, Approaches to Boston Harbor, Massachusetts Bay, Massachusetts: Descriptive Report (DR) H10993, National Oceanic and Atmospheric Administration, National Geophysical Data Center (NGDC), National Geophysical Data Center, Boulder, CO.

    Online Links:

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
    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 Differential Global Positioning System (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).
  3. How accurate are the heights or depths?
    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 TideBot 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.
  4. Where are the gaps in the data? What is missing?
    All quality main survey line bathymetric data (generally shore parallel for the USGS surveys) that were collected within the Duxbury to Hull survey area were incorporated in this grid. 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 from the USGS surveys 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. NOAA's CARIS directory for survey H10993 was provided to the USGS. No additional swath processing or navigation editing was performed to the NOAA data in CARIS. The GPS navigation and bathymetric attitude data were significantly hindered by interference during the first leg of survey 06012 (lines l1f1 - l99f2, 4-14 Aug 2006). Frequent navigation dropouts halted data collection for extended periods during the survey and problems with the ADU2 compass resulted in un-usable bathymetric data along survey tracklines that have valid navigation.
  5. How consistent are the relationships among the observations, including topology?
    This grid represents the un-interpolated data; gaps occurred along-track and between adjacent lines. The NOADATA value when converted to a raster and loaded into ArcMap is 0; although the head of the ASCII file indicates that the NODATA value is 0.000100.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints None
Use_Constraints These data are NOT to be used for navigation. Mariners should refer to the appropriate nautical chart. Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset.
  1. Who distributes the data set? (Distributor 1 of 1)
    Seth Ackerman
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2315 (voice)
    508-457-2310 (FAX)
    sackerman@usgs.gov
  2. What's the catalog number I need to order this data set? Downloadable Data
  3. What legal disclaimers am I supposed to read?
    Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  4. How can I download or order the data?
    • Availability in digital form:
      Data format: WinZip file containing the ARC/INFO ASCII GRID of swath bathymetric data from the Duxbury to Hull survey area. in format AAIGrid (version 9.0) ESRI Raster GRID format Size: 15
      Network links: http://pubs.usgs.gov/of/2009/1072/GIS/raster/bathy/DH_bathy_wgaps.zip
      Media you can order: DVD-ROM (Density 4.75 Gbytes) (format UDF)
      Note: None
    • Cost to order the data: None

  5. What hardware or software do I need in order to use the data set?
    This zip file contains an ARC/INFO ASCII GRID in Environmental Systems Research Institute (ESRI) format. To utilize this data, the user must have a GIS software package capable of importing or converting the ARC/INFO ASCII GRID. A depth-colored hillshade GeoTIFF image of this dataset is also on this report (DH_bathyhlshd_wgaps.tif). The GeoTIFF image version can be viewed with any software capable of opening a TIFF image or in ArcExplorer, a free GIS viewer capable of displaying the GeoTIFF image data (available from ESRI at www.esri.com).

Who wrote the metadata?

Dates:
Last modified: 18-Mar-2024
Metadata author:
Seth Ackerman
U.S. Geological Survey
Geologist
384 Woods Hole Rd.
Woods Hole, MA
USA

508-548-8700 x2315 (voice)
508-457-2310 (FAX)
whsc_data_contact@usgs.gov
Contact_Instructions:
The metadata contact email address is a generic address in the event the person is no longer with USGS. (updated on 20240318)
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/open_file_report/ofr2009-1072/DH_bathy_wgaps.asc.faq.html>
Generated by mp version 2.9.51 on Mon Mar 25 16:05:28 2024