CABATH5MHS - 5 meter ArcRaster Bathymetric Hillshade of both the inshore and offshore portions of the Cape Ann - Salisbury Beach Massachusetts Survey Area

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Frequently-anticipated questions:

What does this data set describe?

Title:
CABATH5MHS - 5 meter ArcRaster Bathymetric Hillshade of both the inshore and offshore portions of the Cape Ann - Salisbury Beach Massachusetts Survey Area
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/html/current_map.html>. 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 should this data set be cited?

    U.S. Geological Survey, 2008, CABATH5MHS - 5 meter ArcRaster Bathymetric Hillshade of both the inshore and offshore portions of the Cape Ann - Salisbury Beach Massachusetts Survey Area: Open-File Report 2007-1373, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole 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, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, Massachusetts.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -70.823419
    East_Bounding_Coordinate: -70.544036
    North_Bounding_Coordinate: 42.900113
    South_Bounding_Coordinate: 42.660349

  3. What does it look like?

    <https://pubs.usgs.gov/of/2007/1373/GIS/browse_jpg/cabath5mhs.jpg> (JPEG)
    black and white thumbnail image of hillshade grid

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

    Beginning_Date: 23-Feb-2004, 20050908
    Ending_Date: 16-Mar-2004, 20050916
    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 5238 x 4468 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 5.000000
      Ordinates (y-coordinates) are specified to the nearest 5.000000
      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?

    cabath5mhs.vat
    Value Attribute Table (Source: ESRI)

    Rowid
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    VALUE
    Calculated Hillshade value (Source: ESRI)

    Range of values
    Minimum:0
    Maximum:254

    COUNT
    Pixel Count (Source: ESRI)

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?

    Brian Andrews
    U.S. Geological Survey
    Geographer
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598
    USA

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

Why was the data set created?

The purpose of this grid is to provide a merged hillshade data set of both the near shore and offshore areas that have no gaps between survey lines in shallow water.

How was the data set created?

  1. From what previous works were the data drawn?

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

    Date: Apr-2008 (process 1 of 1)
    Calculated bathymetric hillshade (cabath5mhs) using the "Hillshade" tool in Spatial Analyst Tools (ArcGIS ArcToolbox ver. 9.2) with following parameters: Input raster: cabath5m Azimuth: 335 Altitude: 45 Model Shadows: NO_SHADOWS Z factor (vertical exaggeration): 1

    No vertical exaggeration was applied.

    Person who carried out this activity:

    Brian Andrews
    U.S. Geological Survey
    Geographer
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598
    USA

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

    Data sources used in this process:
    • cabath5m (This publication)

  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, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    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, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

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

  1. How well have the observations been checked?

    These data have been qualitatively compared to a 1947 NOAA single beam survey. The mean difference between these data and the 1947 survey is 0.18 meters.

  2. How accurate are the geographic locations?

    The horizontal accuracy of this merged grid varies, based on the accuracy of the input grids. The data in "bath_is5m" was collected using a Real-Time Kinematic GPS signal from a USGS base station established for the survey. The data in "bath_os5m" was collected using the Differential Global Positioning System signal from the U.S. Coast Guard.

  3. How accurate are the heights or depths?

    The mean depth differences between nearshore (USGS) survey and the offshore (SAIC) data is 0.24 meters. The data from the two surveys overlap 150-200 meters along there common boundary. In the area of overlap, the offshore data is 0.24 meters (mean) shallower. These differences can be can be attributed to the use of differing tidal models for the two surveys. SAIC utilized a zoned tidal model provided by NOAA, whereas the USGS used kinematic water level heights recorded in real time aboard the R/V Connecticut. A zoned tidal model is based on a compilation of historical water level heights, which take into account extreme highs and lows, and is generally very accurate. However, water level heights at the time of data collection are influenced by local wind and wave setup conditions that are not taken into account by the zoned tidal model. The kinematic water level heights recorded by the USGS aboard the R/V Connecticut reflect these local variations due to wind and wave setup and thus could account for the observed differences in the bathymetric surfaces generated by SAIC and the USGS.

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

    Survey lines run for cross line junction analysis are not included in this grid.

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

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:
Data are not intended for navigational use. The intended scale for these data is 1:25,000. 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 02543
    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?

  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: 06-Jan-2009
Metadata author:
Brian Andrews
U.S. Geological Survey
Geographer
384 Woods Hole Rd.
Woods Hole, MA 02543-1598
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)
Metadata extensions used:

Generated by mp version 2.8.25 on Thu Jan 08 09:07:38 2009