bathy.shp: Digital vector bathymetric/topographic contours of the sea floor in the Stellwagen Bank National Marine Sanctuary region.

Metadata also available as

Frequently-anticipated questions:


What does this data set describe?

Title:
bathy.shp: Digital vector bathymetric/topographic contours of the sea floor in the Stellwagen Bank National Marine Sanctuary region.
Abstract:
This data set contains the sea floor topographic contours generated from a multibeam sonar survey of the Stellwagen Bank National Marine Sanctuary region off Boston, Massachusetts, an area of approximately 1100 square nautical miles. The Stellwagen Bank NMS Mapping Project is designed to provide detailed maps of the Stellwagen Bank region's environments and habitats and the first complete multibeam topographic and sea floor characterization maps of a significant region of the shallow EEZ. Data were collected on four cruises over a two year period from the fall of 1994 to the fall of 1996. The surveys were conducted aboard the Canadian Hydrographic Service vessel Frederick G. Creed, a SWATH (Small Waterplane Twin Hull) ship that surveys at speeds of up to 16 knots. The multibeam data were collected utilizing a Simrad Subsea EM 1000 Multibeam Echo Sounder (95 kHz) that is permanently installed in the hull of the Creed.
  1. How should this data set be cited?

    Valentine, Page C. , Baker, Jessica L. , and Unger, Tanya S. , 2005, bathy.shp: Digital vector bathymetric/topographic contours of the sea floor in the Stellwagen Bank National Marine Sanctuary region.: Scientific Investigations Map 2840, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Page C. Valentine, editor, 2005, Sea Floor Image Maps Showing Topography, Sun-illuminated Topography, Backscatter Intensity, Ruggedness, Slope, and the Distribution of Boulder Ridges and Bedrock Outcrops in the Stellwagen Bank National Marine Sanctuary Region off Boston, Massachusetts: Scientific Investigations Map 2840, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

    Other_Citation_Details: scale 1:60,000, 6 maps, 12 sheets

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -71.021510
    East_Bounding_Coordinate: -69.816685
    North_Bounding_Coordinate: 42.851518
    South_Bounding_Coordinate: 41.666379

  3. What does it look like?

    <http://pubs.usgs.gov/sim/2005/2840/data/bathy/bathy-thumb.gif> (GIF)
    Thumbnail image showing extent and location of bathymetric contours in the Stellwagen Bank National Marine Sanctuary region.
    <http://pubs.usgs.gov/sim/2005/2840/data/bathy/bathy-browse.gif> (GIF)
    Browse image showing extent and location of bathymetric contours in the Stellwagen Bank National Marine Sanctuary region.

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 1994
    Ending_Date: 1998
    Currentness_Reference: ground condition

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: vector digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • String (2335)

    2. What coordinate system is used to represent geographic features?

      The map projection used is Mercator.

      Projection parameters:
      Standard_Parallel: 41.650000
      Longitude_of_Central_Meridian: -70.316667
      False_Easting: 0.000000
      False_Northing: 0.000000

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.000256
      Ordinates (y-coordinates) are specified to the nearest 0.000256
      Planar coordinates are specified in meters

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

  7. How does the data set describe geographic features?

    bathy
    Shapefile Attribute Table (Source: ESRI)

    FID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    FNODE_
    From-node identifier of linear feature carried over from Arc/Info processing and the Arc/Info attribute FNODE_. It is an ArcInfo internal control parameter and has no applicable relevance to the use of the data. (Source: Software Computed)

    Range of values
    Minimum:10
    Maximum:2633
    Units:integer count
    Resolution:1

    TNODE_
    To-node identifier of linear feature carried over from Arc/Info processing and the Arc/Info attribute TNODE_. It is an ArcInfo internal control parameter and has no applicable relevance to the use of the data (Source: Software Computed)

    Range of values
    Minimum:1
    Maximum:2634
    Units:integer count
    Resolution:1

    LPOLY_
    Internal number of polygon to left of arc carried over from Arc/Info processing and the Arc/Info attribute LPOLY_. It is an ArcInfo internal control parameter and has no applicable relevance to the use of the data (Source: Software Computed)

    Range of values
    Minimum:-1
    Maximum:-1
    Units:integer count
    Resolution:1

    RPOLY_
    Internal number of polygon to right of arc carried over from Arc/Info processing and the Arc/Info attribute RPOLY_. It is an ArcInfo internal control parameter and has no applicable relevance to the use of the data. (Source: Software Computed)

    Range of values
    Minimum:-1
    Maximum:-1
    Units:integer count
    Resolution:1

    LENGTH
    Length of the line in native units (Source: User defined)

    Range of values
    Minimum:35.215
    Maximum:116472.308
    Units:meters
    Resolution:.001

    BATHYMER_
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    CONTOUR
    Depth of bathymetric contour. Values are in meters above sea level, so all values are negative. Double of width 13, but values are integer. Another attribute "INTERVAL" contains the same data stored as an integer. (Source: USGS)

    Frequency of measurement: 5 m

    Range of values
    Minimum:-270
    Maximum:-5
    Units:meters
    Resolution:.000

    INTERVAL
    Depth of bathymetric contour, in meters above sea level. (Source: USGS)

    Frequency of measurement: 5 m

    Range of values
    Minimum:-270
    Maximum:-5
    Units:meters
    Resolution:5


Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

  3. To whom should users address questions about the data?

    Page C. Valentine
    U.S. Geological Survey
    Research Geologist
    U.S. Geological Survey
    Woods Hole, MA 02543-1598
    USA

    (508) 548-8700 x2239 (voice)
    (508) 457-2310 (FAX)
    pvalentine@usgs.gov


Why was the data set created?

Development of interpretive seabed maps, sea floor imagery, and a GIS database that are accessible to scientists, policymakers, managers, and the general public.


How was the data set created?

  1. From what previous works were the data drawn?

  2. How were the data generated, processed, and modified?

    (process 1 of 1)
    The navigation and topographic data were both processed using SwathEd, a suite of bathymetric and multibeam software editing and display tools developed by Dr. John Hughes Clarke of the Ocean Mapping Group, University of New Brunswick (UNB). Tidal corrections were obtained from NOAA's Boston Tide Gauge (Station 8443970) and merged into the data set using UNB's tidal routines. The topographic information was converted into an ASCII text file containing lat, long, and depth fields, using a script created by Bill Danforth at the U.S. Geological Survey. The ASCII file was brought into Arc/Info, and a grid was generated and processed using ESRI's Arc/Info version 7.0.4 software. A point coverage containing depth values was created using the routine point-generate. The grid was created based on the depth values for each of the points using the command pointgrid. The grid was filtered with a 9 by 9 focalmedian filter. Contours were generated using latticecontour. All editing and edgematching was done by hand using arcedit.

  3. What similar or related data should the user be aware of?

    Valentine, Page C. , Middleton, Tammie J. , and Fuller, Sarah J. , 2001, Sea floor maps showing topography, sun-illuminated topography, and backscatter intensity of the Stellwagen Bank National Marine Sanctuary region off Boston, Massachusetts: Open-File Report 00-410, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

    Valentine, Page C. , Baker, Jessica L. , and Unger, Tanya S. , 2003, Sea floor topography of the Stellwagen Bank National Marine Sanctuary off Boston, Massachusetts: Geologic Investigations Map I-2676-A, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Valentine, Page C. , Unger, Tanya S. , and Baker, Jessica L. , 2003, Sun-illuminated sea floor topography of the Stellwagen Bank National Marine Sanctuary off Boston, Massachusetts: Geologic Investigations Map I-2676-B, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Valentine, Page C. , Unger, Tanya S. , and Baker, Jessica L. , 2003, Backscatter intensity and sun-illuminated sea floor topography of the Stellwagen Bank National Marine Sanctuary off Boston, Massachusetts: Geologic Investigations Map I-2676-C, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.


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

  1. How well have the observations been checked?

    The ship's position was determined with an accuracy of 10 m or better using a Magnavox 4200 geographic positioning system (GPS) receiver in conjunction with differential GPS corrections transmitted by U.S. Coast Guard radio beacons. Sound velocity information was updated during the day whenever the survey moved from one area to another. Tidal corrections based on NOAA's Boston tide gauge were used to reference depth data to mean lower low water. Sounding rates depend on water depth but vary from 2 to 4 per second in water depths less than 100 meters. Horizontal spatial resolution at these sounding rates is on the order of 10% of the water depth at 16 knots; however, vertical resolution is approximately 1% or better in the same depth range.

  2. How accurate are the geographic locations?

    Sounding rates depend on water depth but vary from 2 to 4 per second in water depths less than 100 meters. Horizontal spatial resolution at these sounding rates is on the order of 10% of the water depth at 16 knots; however, vertical resolution is approximately 1% or better in the same depth range.

  3. How accurate are the heights or depths?

    Sounding rates depend on water depth but vary from 2 to 4 per second in water depths less than 100 meters. Horizontal spatial resolution at these sounding rates is on the order of 10% of the water depth at 16 knots; however, vertical resolution is approximately 1% or better in the same depth range.

  4. Where are the gaps in the data? What is missing?

    The bathymetric data are displayed in real time on the Sun workstation using software designed and written by the Ocean Mapping Group, University of New Brunswick. This display allows data gaps to be identified during the survey and also gives a measure of the data quality.

  5. How consistent are the relationships among the observations, including topology?

    No additional checks for topological consistency were performed on the data.


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:
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.

Bathymetry is not to be used for navigational purposes.

  1. Who distributes the data set? (Distributor 1 of 1)

    Page C. Valentine
    U.S. Geological Survey
    Research Geologist
    U.S. Geological Survey
    Woods Hole, MA 02543-1598
    USA

    (508) 548-8700 x2239 (voice)
    (508) 457-2310 (FAX)
    pvalentine@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?

    Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. 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?

  5. What hardware or software do I need in order to use the data set?

    These data are available in Environmental Systems Research Institute (ESRI) shapefile format. The user must have ArcGIS® or ArcView® 3.0 or greater software to read and process the data file. In lieu of ArcView or ArcGIS, the user may utilize another GIS application package capable of the importing data. A free data viewer, arcexplorer, capable of displaying the data is available from ESRI at www.esri.com.


Who wrote the metadata?

Dates:
Last modified: 22-Aug-2005
Last Reviewed: 22-Aug-2005
Metadata author:
U.S. Geological Survey
c/o Page C. Valentine
Research Geologist
U.S. Geological Survey
Woods Hole, MA 02543-1598
USA

(508) 548-8700 x2239 (voice)
(508) 457-2310 (FAX)
pvalentine@usgs.gov

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:


Generated by mp version 2.8.6 on Mon Aug 22 09:18:36 2005