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2005 single beam bathymetry data collected in South San Francisco Bay, California

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Frequently-anticipated questions:


What does this data set describe?

Title:
2005 single beam bathymetry data collected in South San Francisco Bay, California
Abstract:
XYZ ASCII format data generated from the 2005 single beam acoustic bathymetric survey of South San Francisco Bay, CA. Z-values provided relative to the North American Vertical Datum of 1988 (NAVD88) and to Mean Lower Low Water (MLLW) of the 1983-2001 national tidal datum epoch where possible. Funding provided by the California Coastal Conservancy and survey collected by Sea Surveyor, Inc. of Benicia, CA.

Supplemental_Information:
Bounding ccordinates for ivdividual zones are as follows.

Zone 31  West: -122.24, East: -122.18, North: 37.70, South: 37.67
Zone 33  West: -122.31, East: -122.24, North: 37.67, South: 37.62
Zone 34  West: -122.25, East: -122.17, North: 37.69, South: 37.64
Zone 35  West: -122.28, East: -122.16, North: 37.67, South: 37.61
Zone 36  West: -122.33, East: -122.25, North: 37.64, South: 37.59
Zone 37  West: -122.31, East: -122.15, North: 37.66, South: 37.57
Zone 38  West: -122.26, East: -122.15, North: 37.62, South: 37.55
Zone 39  West: -122.23, East: -122.14, North: 37.60, South: 37.53
Zone 40  West: -122.20, East: -122.12, North: 37.57, South: 37.51
Zone 42  West: -122.17, East: -122.11, North: 37.55, South: 37.49
Zone 43  West: -122.13, East: -122.09, North: 37.52, South: 37.47
Zone 44  West: -122.12, East: -122.05, North: 37.50, South: 37.45
Zone 46  West: -122.06, East: -122.03, North: 37.46, South: 37.45
Zone 47  West: -122.34, East: -122.92, North: 37.47, South: 37.46
Zone 48  West: -122.01, East: -121.98, North: 37.47, South: 37.46
Zone 49  West: -121.98, East: -121.96, North: 37.47, South: 37.47
Zone 50  West: -121.98, East: -121.97, North: 37.46, South: 37.46
Zone 51  West: -121.96, East: -121.95, North: 37.48, South: 37.47
Zone 52  West: -121.97, East: -121.95, North: 37.47, South: 37.46
Zone 53  West: -121.97, East: -121.96, North: 37.46, South: 37.45
Zone 54  West: -121.97, East: -122.00, North: 37.45, South: 37.44
Zone 55  West: -122.02, East: -122.01, North: 37.46, South: 37.45
Zone 56  West: -122.00, East: -121.99, North: 37.45, South: 37.43
Zone 57  West: -121.99, East: -121.98, North: 37.43, South: 37.42
Zone Upper Mud  West: -121.95, East: -121.93, North: 37.47, South: 37.45
Zone Upper Coyote  West: -121.95, East: -121.95, North: 37.48, South: 37.48
Zone Upper Artesian  West: -121.96, East: -121.96, North: 37.44, South: 37.44
Zone QC Lines  West: -122.31, East: -122.12, North: 37.69, South: 37.51
  1. How should this data set be cited?

    Jaffe, Bruce, 2007, 2005 single beam bathymetry data collected in South San Francisco Bay, California:.

    This is part of the following larger work.

    Foxgrover, A., Jaffe, B., Hovis, G., Martin, C, 2007, 2005 Hydrographic Survey of South San Francisco Bay, California: Open-File Report 2007-1169, U.S. Geological Survey, Menlo Park, CA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -122.34
    East_Bounding_Coordinate: -121.92
    North_Bounding_Coordinate: 37.70
    South_Bounding_Coordinate: 37.42

  3. What does it look like?

    <http://walrus.wr.usgs.gov/infobank/b/b105sf/html/b-1-05-sf.nav.html> (GIF)
    Image showing location and extent of B-1-05-SF data.

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

    Beginning_Date: 10-Jan-2005
    Ending_Date: 05-Apr-2005
    Currentness_Reference: publication date

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

    Geospatial_Data_Presentation_Form: tabular digital data

  6. How does the data set represent geographic features?

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

      This is a Point data set.

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

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 10
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -123.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.000064
      Ordinates (y-coordinates) are specified to the nearest 0.000064
      Planar coordinates are specified in meters

      The horizontal datum used is NAD83.
      The ellipsoid used is GRS80.
      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?

    Entity_and_Attribute_Overview:

    Sample of Bathymetry XYZ ASCII file
    X(UTM, m),   Y(UTM, m),    Depth(m, MLLW)
    
    571247.445,  4172178.538,  -0.213
    571246.972,  4172179.416,  -0.213
    571246.452,  4172180.270,  -0.274
    571245.662,  4172180.879,  -0.305
    571244.849,  4172181.458,  -0.335
    571243.978,  4172181.944,  -0.335
    571243.130,  4172182.460,  -0.396
    571242.222,  4172182.875,  -0.427
    571241.337,  4172183.342,  -0.457
    571240.447,  4172183.797,  -0.518
    
    Entity_and_Attribute_Detail_Citation: none


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?

    Bruce Jaffe
    U.S. Geological Survey, Coastal and Marine Geology
    Physical Oceanographer
    400 Natural Bridges Dr
    Santa Cruz, CA 95060-5792
    USA

    (831) 427-4742 (voice)
    (831) 427-4748 (FAX)
    bjaffe@usgs.gov


Why was the data set created?

These data are intended for science researchers, students, policy makers, and the general public. The data can be used with Geographic Information Systems (GIS) or other software to display bathymetry data of South San Francisco Bay, CA.


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: 04-May-2007 (process 1 of 1)
    The single beam bathymetric data was collected using an INNERSPACE Model 455 survey-grade depthfinder with 3-degree, 200kHz transducer. The depthfinder collects 20 soundings/second typically resulting in a nominal spacing of 0.15m along trackline. Tracklines are oriented perpendicularly to the slope of the bay floor and spaced 100 m apart. The data were reduced to the Mean Lower Low Water (MLLW) datum of the 1983 to 2001 epoch using a tidal reduction scheme created by NOAA consisting of specific time and range corrections for discrete zones within South SF Bay. After reducing the soundings to a common vertical datum, they were thinned to 1 m spacing along tracklines. (Reduction methodologies for soundings collected in Coyote Creek and the adjacent sloughs varied, please see details contained in the body of OF-1169). NOAA also calculated offset values for the difference between the tidal datum of MLLW and the geodetic datum of NAVD88. This offset was calculated for all zones except 51-54. All soundings except those in zones 51-54 are available relative to MLLW and soundings for the entire survey are available relative to NAVD88. Seperate X,Y,Z ASCII files for each vertical datum are provided.

    Person who carried out this activity:

    Bruce Jaffe
    U.S. Geological Survey, Coastal and Marine Geology
    Physical Oceanographer
    400 Natural Bridges Dr
    Santa Cruz, CA 95060-5792
    USA

    (831) 427-4742 (voice)
    (831) 427-4748 (FAX)
    bjaffe@usgs.gov

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

    U.S. Geological Survey, Coastal and Marine Geology Program, 2007, InfoBank.

    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?

    +/- 3 meters

  3. How accurate are the heights or depths?

    in the bay, +/- 6 cm; in the sloughs and creeks, +/- 15 cm. Depths reduced to MLLW vertical datum.

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

    Soundings were collected during periods of high tide in order to optimize Òbank-to-bankÓ coverage of South Bay tidal flats, and provide maximum overlap with the aerial topographic LIDAR data collected months earlier during periods of low tide.

    Soundings were collected across South San Francisco Bay along tracklines spaced at nominal 100m intervals and oriented in a southwest-northeast direction (perpendicular to the general bathymetric contour of the seafloor). Survey tracklines were divided into tide zones defined by NOAA (2006), with 100m overlap into adjacent zones. Dividing the tracklines into tide zone simplified processing the soundings and provided a QC check in the overlap area around tide zone boundaries. Unless obstructions were encountered, soundings near the shoreline extend to elevation +0.3m MLLW or higher. When practical, soundings were collected around obstructions to complete sounding lines. Overlap between survey areas and cross-lines (tielines) are provided for quality-control assessment of the soundings. Soundings were collected during all stages of the tide, provided that sufficient water depth was available for safe navigation. Areas shallower than Ð1m MLLW were surveyed during periods of extreme high tides when the water surface elevation is +1.75m MLLW or higher. Areas deeper than Ð3m MLLW were surveyed during all stages of the tide (high and low), but always during periods of ÒneapÓ tides when the water surface elevation changes less than 1.25m between high and low tides. Survey lines terminated early because of shallow water during low or moderate tides were re-surveyed during extreme high tides in order to collect soundings as far upland as possible. For QC purposes, survey lines terminated early at low tide are re-surveyed at high tide with a minimum 100m overlap.

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

    To make the soundings comparable to historical data, water depths were measured and corrected for tide using the same methods as used during the more recent of the historical surveys of South San Francisco Bay. Soundings were collected using a single-beam, survey-grade depthfinder having the same frequency and beam-width as used during the more recent of the historical surveys. Soundings were corrected to the MLLW vertical datum using tide data measured at the same location and reduced by the same organization (NOAA) as historical surveys.

    Soundings from the hydrographic survey are in meters referenced to two separate vertical datum, including MLLW and NAVD-88. USGS will compare soundings referenced to MLLW to historical NOS surveys of South San Francisco Bay, and merge soundings referenced to NAVD-88 with the May 2004 LIDAR topographic data to create a terrain model of existing land surface elevation and bay bathymetry.


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:

Please recognize the U.S. Geological Survey (USGS) and the California Coastal Conservancy as the source of this information. USGS-authored or produced data and information are in the public domain.

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

    U.S. Geological Survey, Coastal and Marine Geology
    c/o Bruce Jaffe
    400 Natural Bridges Dr
    Santa Cruz, CA 95060-5792
    USA

    (831) 427-4742 (voice)

  2. What's the catalog number I need to order this data set?

  3. What legal disclaimers am I supposed to read?

    These data not intended for navigational purposes.

    Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, these data and information are provided with the understanding that they are not guaranteed to be usable, timely, accurate, or complete. Users are cautioned to consider carefully the provisional nature of these data and information before using them for decisions that concern personal or public safety or the conduct of business that involves substantial monetary or operational consequences. Conclusions drawn from, or actions undertaken on the basis of, such data and information are the sole responsibility of the user.

    Neither the U.S. Government nor any agency thereof, 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 data, software, information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights.

    Trade, firm, or product names and other references to non-USGS products and services are provided for information only and do not constitute endorsement or warranty, express or implied, by the USGS, US DOI, or U.S. Government, as to their suitability, content, usefulness, functioning, completeness, or accuracy.

  4. How can I download or order the data?


Who wrote the metadata?

Dates:
Last modified: 04-May-2007
Metadata author:
Amy Foxgrover
U.S. Geological Survey, Coastal and Marine Geology
Geographer
400 Natural Bridges Dr
Santa Cruz, CA 95060-5792
USA

(831) 427-4743 (voice)
(831) 427-4748 (FAX)
afoxgrover@usgs.gov

Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)


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