Q1_1MCTR.SHP - 1-m interval contours of smoothed multibeam bathymetry in western Massachusetts Bay map Quadrangle 1

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Frequently-anticipated questions:

What does this data set describe?

Title:
Q1_1MCTR.SHP - 1-m interval contours of smoothed multibeam bathymetry in western Massachusetts Bay map Quadrangle 1
Abstract:
The U.S. Geological Survey has conducted geologic mapping to characterize the sea floor offshore of Massachusetts. The mapping was carried out using a Simrad Subsea EM 1000 Multibeam Echo Sounder on the Frederick G. Creed on four cruises conducted between 1994 and 1998. The mapping was conducted in cooperation with the National Oceanic and Atmospheric Administration (NOAA) and with support from the Canadian Hydrographic Service and the University of New Brunswick. The long-term goal of this mapping effort is to produce high-resolution geologic maps and a Geographic Information System (GIS) project that presents images and grids of bathymetry, shaded relief bathymetry, and backscatter intensity data from these surveys that will serve the needs of research, management and the public.
  1. How should this data set be cited?

    Butman, Bradford, 2007, Q1_1MCTR.SHP - 1-m interval contours of smoothed multibeam bathymetry in western Massachusetts Bay map Quadrangle 1: Data Series 99, 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.

    Butman, Bradford, Valentine, Page C., Middleton, Tammie J., and Danforth, William W., 2007, A GIS Library of Multibeam Data for Massachusetts Bay and the Stellwagen Bank National Marine Sanctuary, Offshore of Boston, Massachusetts: Data Series 99, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -70.781416
    East_Bounding_Coordinate: -70.600055
    North_Bounding_Coordinate: 42.322212
    South_Bounding_Coordinate: 42.203387

  3. What does it look like?

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

    Beginning_Date: 1994
    Ending_Date: 1998
    Currentness_Reference: publication date

  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 (1710)

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

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000000. Longitudes are given to the nearest 0.000000. Latitude and longitude values are specified in Decimal degrees.

      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.

      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: Mean lower low water
      Depth_Resolution: 0.5
      Depth_Distance_Units: Meters
      Depth_Encoding_Method: Explicit depth coordinate included with horizontal coordinates

  7. How does the data set describe geographic features?

    q1_1mctr

    FID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    FNODE_
    internal number of start x,y coordinate pair for the arc (Source: USGS)

    Range of values
    Minimum:1
    Maximum:2824
    Units:integer

    TNODE_
    internal number of end x,y coordinate pair for the arc (Source: USGS)

    Range of values
    Minimum:1
    Maximum:2821
    Units:integer

    RPOLY_
    internal number of the polygon to the right of the arc (Source: USGS)

    Range of values
    Minimum:1
    Maximum:2
    Units:integer

    LPOLY_
    internal number of the polygon to the left of the arc (Source: USGS)

    Range of values
    Minimum:1
    Maximum:2
    Units:integer

    LENGTH
    length of the arc (Source: USGS)

    Range of values
    Minimum:0.8518
    Maximum:2140.2153
    Units:meters

    CONTOUR
    depth in meters for bathymetric contours (Source: USGS)

    Range of values
    Minimum:17
    Maximum:64
    Units:meters
    Resolution:1

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?

    U.S. Geological Survey
    c/o Bradford Butman
    Oceanographer
    384 Woods Hole Rd
    Woods Hole, MA 02543-1598
    USA

    (508) 548-8700 x2212 (voice)
    (508) 457-2309 (FAX)
    bbutman@usgs.gov

    Hours_of_Service: 8 a.m. - 5 p.m.

Why was the data set created?

This shapefile shows sea floor bathymetry as contours at 1-m intervals in western Massachusetts Bay map Quadrangle 1. The contours were derived from a 6-m resolution grid of multibeam data (q1_bathy6m) that had been smoothed over a 9-cell by 9-cell rectangle using the "focalmedian" routine.

How was the data set created?

  1. From what previous works were the data drawn?

    q1_bathy6m (source 1 of 1)
    U.S. Geological Survey, 2007, Q1_BATHY6M - 6 meter grid of the Quad1 multibeam bathymetry for western Massachusetts Bay: Data Series 99, 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.

    Butman, Bradford, Valentine, Page C., Middleton, Tammie J., and Danforth, William W., 2007, A GIS Library of Multibeam Data for Massachusetts Bay and the Stellwagen Bank National Marine Sanctuary, Offshore of Boston, Massachusetts: Data Series 99, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

    Type_of_Source_Media: disc
    Source_Contribution: Grid data contoured using Arc/Info.

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

    Date: Feb-2007 (process 1 of 1)
    Bathymetric contours at 1-m intervals were derived from a 6-m resolution grid of multibeam bathymetry using the "latticecontour" routine. The 6-m grid (q1_bathy6m) was smoothed over a 9-cell by 9-cell rectangle using the "focalmedian" function in ARCGRID. The contours were converted to a shapefile in ArcGIS.

    Person who carried out this activity:

    William Danforth
    U.S. Geological Survey
    Operational Geologist
    384 Woods Hole Road
    Woods Hole, MA 02543-1598
    USA

    (508) 548-8700 x2274 (voice)
    (508) 457-2310 (FAX)
    bdanforth@usgs.gov

    Data sources used in this process:
    • q1_bathy6m

    Data sources produced in this process:

    • q1_1mctr.shp
    • q1_1mctr.dbf
    • q1_1mctr.shx

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

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

  1. How well have the observations been checked?

    Data were verified by plotting over acquired bathymetric data and visually matching contours with depth values.

  2. How accurate are the geographic locations?

    These data were navigated with a Differential Global Positioning System (DGPS); they are accurate to +/- 3 meters, horizontally.

  3. How accurate are the heights or depths?

    These data have been corrected for vessel motion (roll, pitch, heave, yaw) and tidal offsets, and referenced to mean lower low water. The theoretical vertical resolution of the Simrad EM-1000 multibeam echosounder is 1 % of water depth, approximately 0.3 - 1.0 m within the study area.

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

    The multibeam bathymetric data, on which these contours are based, were corrected for tidal elevation during the survey using sea level measured at the NOAA Boston tide gage. This assumes that the tidal elevation and phase are the same as Boston across the survey area. Further processing to correct for the spatial and temporal changes in tidal elevation across the survey area may be undertaken at a later time.

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

    These data are logically consistent.

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 purposes. 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 (USGS) as the source of this information.

  1. Who distributes the data set? (Distributor 1 of 2)

    Bradford Butman
    U.S. Geological Survey
    Oceanographer
    384 Woods Hole Road
    Woods Hole, Massachusetts 02543-1598
    USA

    (508) 548-8700 x2212 (voice)
    (508) 457-2309 (FAX)
    bbutman@usgs.gov

    Hours_of_Service: 8 a.m. to 5 p.m. EST
  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 (USGS), U.S. Department of the Interior (DOI), no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. 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?

  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.

  1. Who distributes the data set? (Distributor 2 of 2)

    U.S. Geological Survey Information Services
    Box 25286 Denver Federal Center
    Denver, Colorado 80225-0046
    USA

    (303) 202-4700 (voice)
    (303) 202-4188 (FAX)

    Hours_of_Service: 8 a.m. to 5 p.m. Mountain Time
  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 (USGS), U.S. Department of the Interior (DOI), no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. 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?

  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: 27-Mar-2007
Metadata author:
Bradford Butman
U.S. Geological Survey
Oceanographer
384 Woods Hole Road
Woods Hole, MA 02543-1598
USA

(508) 548-8700 x2212 (voice)
(508) 457-2310 (FAX)
bbutman@usgs.gov

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

Generated by mp version 2.9.1 on Wed Mar 28 06:56:17 2007