CABATH5M - 5 meter ArcRaster Bathymetric grid of both the inshore and offshore area of Cape Ann - Salisbury Beach Survey Area.

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Frequently-anticipated questions:


What does this data set describe?

Title:
CABATH5M - 5 meter ArcRaster Bathymetric grid of both the inshore and offshore area of Cape Ann - Salisbury Beach 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, CABATH5M - 5 meter ArcRaster Bathymetric grid of both the inshore and offshore area of Cape Ann - Salisbury Beach 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/cabath5m.jpg> (JPEG)
    black and white thumbnail image of bathymetry

  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?

    value
    Depth in meters below mean lower low water (Source: ESRI)

    Range of values
    Minimum:-2.9
    Maximum:-91.37
    Units:meters

    Entity_and_Attribute_Overview:
    Data depth values represent depth in meters referenced to mean lower low water (MLLW).


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 bathymetric dataset of the nearshore and offshore survey areas that covers 100 percent of the seafloor inside the Cape Ann to Salisbury Beach survey areas.


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 3)
    Filled in the small gaps between adjacent lines in the near shore survey area (bath_is5m) using several steps outlined below:

    1) Calculated new grid by selecting all areas in bath_is5m with a depth less than 14m deep using ESRI ArcInfo Workstation (ver 9.2 ) Grid Module Syntax= EXT14M = select((bath5mfinal), 'value > -14')

    2) Converted the temporary grid of depth less than 14 meters to a point feature class using the "Raster to Point" tool (ArcGIS ArcToolbox ver. 9.2).

    3) Create empty TIN using "Create TIN" tool, then add x,y,z point feature class using the "Edit TIN" tool (ArcGIS ArcToolbox ver. 9.2). Creating a TIN from the points filled in the gaps between lines.

    4) Created a polygon feature class to use as a hard clip boundary and then added to the TIN with the "Edit TIN" Tool (ArcGIS ArcToolbox ver. 9.2).

    5) Converted the TIN back to a 10 meter resolution grid (nn10mfil) using "Tin to Raster" Tool (ArcGIS ArcToolbox ver 9.2) using the natural neighbors and 10 m cell size option. A 10m cell size was used to further smooth the data.

    6) Mosaicked the 5m inshore grid (bath_is5m with gaps) with the 10m inshore grid (<14m with no gaps) into a new 5m grid (bath_is5mInt) covering the near shore survey area. Used the "Mosaic To New Raster" tool (ArcGIS ArcToolbox ver. 9.2) with the following parameters: Input Rasters: nn10mfil, bath_is5m Output Raster: is5m_merge Cellsize: 5

    Mosaic Method: First- This option means the output cell value of the overlapping areas will be the value from the first raster in the list (bath_is5m). Where the two grids do not overlap (the gaps) the nn10mfil values we used.

    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:
    • bath_is5m (this publication)

    Data sources produced in this process:

    • bath_is5mInt. (temporary grid)

    Date: Apr-2008 (process 2 of 3)
    Depths in the areas of overlap between the nearshore and offshore data were compared prior to mosaicking the two together. The summary statistics for the area of overlap:

    Count: 131,668 Min: -4.23 meters Max 2.77 meters Mean: -0.24 meters Standard Deviation: 0.177 meters

    The offshore data (SAIC RESON 8101) is 0.24 meters shallower than the USGS inshore data. A correction factor of 0.24 meters was added to the inshore data so that the mosaicked bathymetric grid would not have a big depth difference along the area of overlap.

    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:
    • bath_is5m (this publication)

    Date: Apr-2008 (process 3 of 3)
    Mosaicked the inshore bathymetry (bath_is5mInt with no gaps) with the offshore bathymetry (bath_os5m) to create a continuous regional bathymetric surface (cabath_5m) covering both survey areas. Used the "Mosaic To New Raster" tool (ArcGIS ArcToolbox ver 9.2). The mosaic method used the "Last" option so that in the area of overlap the new grid used the last raster in the list (bath_os5m).

    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:
    • bath_is5m (this publication)
    • bath_os5m (this publication)

    Data sources produced in this process:

    • cabath_5m (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?

  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 of 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 09:07:37 2009