5 meter ArcRaster grid of swath bathymetry of inshore area of Cape Ann - Salisbury Beach Massachusetts survey area (BATH_IS5m, UTM Zone 19, WGS84)

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Frequently anticipated questions:


What does this data set describe?

Title:
5 meter ArcRaster grid of swath bathymetry of inshore area of Cape Ann - Salisbury Beach Massachusetts survey area (BATH_IS5m, 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, Coastal and Marine Geology Program, Woods Hole Science Center. 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 reserves, and assessing environmental changes due to natural or human impacts. The project is focused on the inshore waters (5-30m 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/>. This spatial dataset is from the Cape Ann and Salisbury Beach Massachusetts project area. They were collected in two separate surveys in 2004 and 2005 and cover approximately 325 square kilometers of the inner continental shelf. High resolution bathymetry and backscatter intensity were collected in 2004 and 2005. Seismic profile data, sediment samples and bottom photography were also collected in 2005.
  1. How might this data set be cited?
    U.S. Geological Survey, 2008, 5 meter ArcRaster grid of swath bathymetry of inshore area of Cape Ann - Salisbury Beach Massachusetts survey area (BATH_IS5m, UTM Zone 19, WGS84): Open-File Report 2007-1373, 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., Andrews, Brian D., Ackerman, Seth D., Baldwin, Wayne E., and Hein, Christopher J., 2008, 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:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -70.811735
    East_Bounding_Coordinate: -70.650661
    North_Bounding_Coordinate: 42.864755
    South_Bounding_Coordinate: 42.660515
  3. What does it look like?
    http://pubs.usgs.gov/of/2007/1373/GIS/browse_jpg/bath_is5m.jpg (JPEG)
    black and white thumbnail image of bathymetry.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 08-Sep-2005
    Ending_Date: 16-Sep-2005
    Currentness_Reference:
    ground condition
  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 4484 x 2544 x 1, type Grid Cell
    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 5.001966
      Ordinates (y-coordinates) are specified to the nearest 5.001966
      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.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: mean lower low water
      Altitude_Resolution: 0.1
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method: attribute values
  7. How does the data set describe geographic features?
    Value
    Depth in meters below mean lower low water (Source: ESRI)
    Information unavailable from original metadata.
    Information unavailable from original metadata. (Source: Information unavailable from original metadata.)
    Range of values
    Minimum:-2.5
    Maximum:-28.8
    Units:meters
    Entity_and_Attribute_Overview:
    Swath bathymetry in ESRI ArcRaster format. Data values represent depth in meters referenced to mean lower low water (MLLW).
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey

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?
    Brian Andrews
    U.S. Geological Survey
    Geographer
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2348 (voice)
    508-457-2310 (FAX)
    bandrews@usgs.gov

Why was the data set created?

The purpose of these data is to establish high-resolution acoustic depth measurements of the seafloor for regional geologic framework investigations. These data cover 69 square kilometers of the near shore survey area between Cape Ann and Salisbury Beach, Massachusetts, in depths between 2m and 30m.

How was the data set created?

  1. From what previous works were the data drawn?
    raw data (source 1 of 1)
    Information unavailable from original metadata., unpublished material, Raw data collected for field activitie 2005-005-FA.

    Other_Citation_Details:
    The source citation information is inferred from other information in the metadata and was not part of the original metadata file. Source time period of content was inferred from the time period of the dataset.
    Type_of_Source_Media: Information unavailable from original metadata.
    Source_Contribution:
    System Setup and Operation: The Systems Engineering and Assessment (SEA) Ltd. SwathPlus bathymetric sonar was configured in a rigid pole-mount and deployed from the starboard side of the R/V Connecticut. A TSS DMS 2-05 motion sensor was mounted directly above and in-line with the transducers. An RTK-GPS antenna was mounted adjacent to the rigid-pole mount. 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. An Applied Microsystems SV Plus sound velocity profiler was used to collect speed of sound profiles at forty-two stations. A patch test was conducted at the beginning of the survey in order to measure roll angle offsets. Roll angle offsets can have a strong effect on the accuracy of depth measurements. (The roll angle offset is the difference between the motion sensor vertical measurement and the nominal mount angle of the transducers (30 degrees)). The calculated roll angle offsets were stored within the SEA Swath Processor acquisition software. Navigation: The USGS established a Real-Time Kinematic Global Positioning System (RTK-GPS) that provided horizontal (x and y) and vertical (z) positioning during the survey. The RTK-corrected GPS signal was sent to the ship once every second from a base station positioned on the roof of the Air Force Antenna Station (USAF/AFRC/SNHA) in Ipswich, Massachusetts. Shipboard navigation data (x, y, and z) were stored in Hypack, Inc. Hydrographic Survey Software (http://www.hypack.com) raw data files and used for positioning of geophysical instrumentation. The offset between orthometric (NAVD88) and local chart datum (MLLW) as reported at the NOAA Tidal Station #8440452, Parker River National Wildlife Refuge, was applied to the RTK signal. This allows for elevations (z) received at the shipboard RTK antenna to be referenced to Mean Lower Low Water (MLLW) (that is, elevations are stored as distance of the RTK antenna above MLLW). During post-processing, the distance of the RTK antenna above the water-line is removed from the stored RTK elevations. The resulting value is then applied to the bathymetric soundings, yielding data referenced to MLLW.
  2. How were the data generated, processed, and modified?
    Date: Apr-2008 (process 1 of 6)
    Tidal correction: 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" and smoothed in MatLab (ver. 7.1.0.183 R14) 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" . This text file was then inserted in the tide table in the SEA Swath Processor file (*.sxs) for merging with the SwathPlus Raw (*.sxr) file. Person who carried out this activity:
    Brian Andrews
    U.S. Geological Survey
    Geographer
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2348 (voice)
    508-457-2310 (FAX)
    bandrews@usgs.gov
    Date: Apr-2008 (process 2 of 6)
    Raw to Processed Conversion: Each raw SwathPlus bathymetric sonar file (*.sxr) was converted to a SwathPlus processed file (*.sxp) using SEA Swath Processor (ver. 3.05.92). 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 such as range and nadir to eliminate outliers. During this conversion process the tidal information from the previous process step was merged into the new processed file (*.sxp). Person who carried out this activity:
    Brian Andrews
    U.S. Geological Survey
    Geographer
    384 Woods Hole Rd
    Woods Hole, MA
    USA

    508-548-8700 x2348 (voice)
    508-457-2310 (FAX)
    bandrews@usgs.gov
    Date: Apr-2008 (process 3 of 6)
    CARIS Processing: A new CARIS 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. 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 anomalies. Filters were applied to each line including beam to beam slopes and across track angle = 6.0 degrees. The CARIS refraction editor was used to adjust the speed of sound in some cases to flatten out the depth profiles produced by local differences in speed of sound. Person who carried out this activity:
    Brian Andrews
    U.S. Geological Survey
    Geographer
    384 Woods Hole Rd
    Woods Hole, MA
    USA

    508-548-8700 x2348 (voice)
    508-457-2310 (FAX)
    bandrews@usgs.gov
    Date: Apr-2008 (process 4 of 6)
    CARIS to ESRI Conversion: The CARIS HIPS BASE surface was converted to an ArcGIS 32-bit floating point raster grid in a three step process. First, the CARIS BASE surface was imported to Interactive Visualization Systems (IVS) Data Magician (DMagic ver. 6.5.1) .dtm and .geo format. Second, the DMagic file was exported to an ASCII Raster format with ESRI header. Finally the third step imported the ASCII raster file into an ArcGIS 32-bit floating point raster grid (bath_is5m) using the ArcToolbox (ArcGIS ver. 9.2) Conversion Tools-"ASCII to Raster Tool". Person who carried out this activity:
    Brian Andrews
    U.S. Geological Survey
    Geographer
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2348 (voice)
    508-457-2310 (FAX)
    bandrews@usgs.gov
    Date: 05-Nov-2015 (process 5 of 6)
    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. This file had a source contribution, but no source citation information. This information was populated based on information in the source contribution. The distribution format was edited from zip to AIG, based on information contained in the last original process step. AIG indicates Arc/Info Binary Grid. 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: 14-Feb-2017 (process 6 of 6)
    Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alan O. Allwardt
    Contractor -- Information Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7551 (voice)
    831-427-4748 (FAX)
    aallwardt@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:


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?
    These data were navigated using Real-Time Kinematic Global Positioning System (RTK-GPS) which provides horizontal positional accuracies (x and y) 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?
    Vertical accuracy of the acquisition system may approximate 1% of water depth, 0.1-0.3 meters within the survey area. However, overall vertical accuracies of <= 0.5 m are assumed based on the following considerations. Ship motion was recorded with a TSS DMS 2-05 and used to correct for heave, pitch, roll and yaw. RTK-GPS was used to establish water-level heights relative to Mean Lower Low Water (MLLW), providing decimeter-scale accuracies. 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. Fluctuations in the vessel draft due to fuel and water usage were not determined.
  4. Where are the gaps in the data? What is missing?
    Soundings were processed and edited using CARIS 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. Swath bathymetry was collected along additional offshore tie-lines for use with the seismic profiles and for cross-track depth comparison. Bathymetric data collected on these offshore tie lines are not included in this grid.
  5. How consistent are the relationships among the observations, including topology?
    Information unavailable from original metadata.

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:
Intended scale of data is 1:25,000. Data are not intended for navigational use. Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information.
  1. Who distributes the data set? (Distributor 1 of 1)
    Brian Andrews
    U.S. Geological Survey, Woods Hole Science Center
    Geographer
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2348 (voice)
    bandrews@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 ArcRaster grid of swath bathymetric data collected in the near shore survey area of the Cape Ann to Salisbury Beach Survey Area. in format AIG (version 9.0) ESRI Raster GRID format Size: 6.2
      Network links: http://pubs.usgs.gov/of/2007/1373/GIS/raster/bathymetry/bath_is5m.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?
    These data are available as a ArcInfo 32-bit floating point binary grid in Environmental Systems Research Institute (ESRI) format. The grid consists of two folders, one with the "grid name", and one "info" folder. The two folders for each grid are compressed into one file using WinZip (ver. 9.0) software. To utilize these data, the user must have software capable of uncompressing the WinZip file and importing and viewing an ESRI ArcRaster grid. The two folders for each grid must be uncompressed to the same folder. If during the process of extracting multiple grids in WinZip format to the same folder, the user is prompted by WinZip software to "overwrite existing files" in the info folder select the "yes" option.

Who wrote the metadata?

Dates:
Last modified: 02-Dec-2017
Metadata author:
Brian Andrews
U.S. Geological Survey
Geographer
384 Woods Hole Rd.
Woods Hole, MA
USA

508-548-8700 x2348 (voice)
508-457-2310 (FAX)
bandrews@usgs.gov
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/eastcoast/gome/capeann_salisbury/bath_is5m.grd.faq.html>
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