10 meter bathymetric contours of the Gulf of the Farallones region (10mCONTOUR)

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Frequently anticipated questions:

What does this data set describe?

Title:
10 meter bathymetric contours of the Gulf of the Farallones region (10mCONTOUR)
Abstract:
In 1989, the U.S. Geological Survey (USGS) began a major geologic and oceanographic investigation of the Gulf of the Farallones continental shelf system, designed to evaluate and monitor human impacts on the marine environment (Karl and others, 2002). The study region is located off the central California coast, adjacent to San Francisco Bay and encompasses the Gulf of the Farallones National Marine Sanctuary. Geologic mapping of this area included the use of various remote sensing and sampling techniques such as sub-bottom profiling, sidescan-sonar and bathymetric mapping, gravity core and grab sampling, and photography. These data were used to define the surficial sediment distribution, underlying structure and sea floor morphology of the study area. The primary focus of this report is to present a georeferenced, digital sidescan-sonar mosaic of the study region. The sidescan-sonar data were acquired with the AMS-120 (120kHz) sidescan-sonar system during USGS cruise F9-89-NC. The dataset covers approximately 1000 km squared of the continental shelf between Point Reyes, California and Half Moon Bay, California, extending west to the continental shelf break near the Farallon Islands. The sidescan-sonar mosaic displays a heterogenous sea-floor environment, containing outcropping rock, ripples, dunes, lineations and depressions, as well as flat, featureless sea floor (Karl and others, 2002). These data, along with sub-bottom interpretation and ground truth data define the geologic framework of the region. The sidescan-sonar mosaic can be used with supplemental remote sensing and sampling data as a base for future research, helping to define the local current regime and predominant sediment transport directions and forcing conditions within the Gulf of Farallones.
  1. How might this data set be cited?
    Sweeney, Edward M., 2004, 10 meter bathymetric contours of the Gulf of the Farallones region (10mCONTOUR): Open-File Report 2004-1082, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Sweeney, Edward M., Danforth, William W., Karl, Herman A., O'Brien, Thomas F., and Schwab, William C., 2004, The Gulf of Farallones: Sidescan-Sonar Imagery: Open-File Report 2004-1082, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -123.432658
    East_Bounding_Coordinate: -122.642339
    North_Bounding_Coordinate: 38.182490
    South_Bounding_Coordinate: 37.366379
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2001
    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 (44)
    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 0.000089992. Longitudes are given to the nearest 0.000089992. Latitude and longitude values are specified in Decimal degrees. 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?
    10mContour
    ESRI 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.
    ID
    Internal identification value. (Source: ESRI) Identification number generated internally.
    CONTOUR
    Contour interval in meters (Source: USGS)
    Range of values
    Minimum:-200
    Maximum:-10
    Units:meters
    Resolution:10

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Edward M. Sweeney
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    U.S. Geological Survey
    Attn: Edward M. Sweeney
    Research Assistant
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    (508) 548-8700 (voice)
    (508) 457-2310 (FAX)

Why was the data set created?

The 10m contour ESRI vector shapefile serves as continental shelf bathymetric reference information for GIS mapping and the viewing of the Gulf of the Farallones sidescan-sonar data set.

How was the data set created?

  1. From what previous works were the data drawn?
    NGDC Coastal Relief Model (source 1 of 1)
    National Geophysical Data Center (NGDC), 2001, Coastal Relief Model, Central Pacific Coast, Vol 7.

    Online Links:

    Type_of_Source_Media: CD-ROM
    Source_Contribution:
    The ESRI Grid generated from the NGDC Coastal Relief Model was used to generate the 10 meter bathymetric contours.
  2. How were the data generated, processed, and modified?
    Date: 2004 (process 1 of 5)
    Contour intervals were created using the Spatial Analysis extension of the ESRI ArcMap program. For visual effectiveness, contours were created between the depths of -40 meters and -200 meters. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Edward M. Sweeney
    Research Assistant
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    (508) 548-8700 (voice)
    (508) 457-2310 (FAX)
    Date: 14-Nov-2016 (process 2 of 5)
    Edits to the metadata were made to fix any errors that MP v 2.9.34 flagged. This is necessary to enable the metadata to be successfully harvested for various data catalogs. In some cases, this meant adding text "Information unavailable" or "Information unavailable from original metadata" for those required fields that were left blank. Other minor edits were probably performed (title, publisher, publication place, etc.). The metadata date (but not the metadata creator) was edited to reflect the date of these changes. The metadata available from a harvester may supersede metadata bundled within a download file. Compare the metadata dates to determine which metadata file is most recent. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 20-Jul-2018 (process 3 of 5)
    USGS Thesaurus keywords added to the keyword section. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 18-Nov-2019 (process 4 of 5)
    Crossref DOI link was added as the first link in the metadata. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 08-Sep-2020 (process 5 of 5)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
  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?
    These data were generated from an ESRI grid of the NGCD Coastal Relief Model. The accuracy of these data are inherited from the Coastal Relief Model. Soundings for each volume of the Coastal Relief model series are compiled from hydrographic surveys conducted by the National Ocean Service (NOS) and from various academic institutions. The surveys were carried out using a variety of sounding methods including SeaBeam 16-beam, 12-kHz swath mapping system (6000- >3000m operating water depths), General Instruments 17-beam, 36-kHz Hydrochart II swath mapping system (5-150m operating water depths), single-beam echosounder (e.g., 3.5 kHz narrow 2 degree beam), and lead-line sounding method. These latter surveys date as far back as the late 1800's. A wide range of navigation methods are also associated with the surveys. Visual navigation is based on three-point sextant fixes, theodolite intersections, and celestial fixes. Electronic navigation involves short to long range positioning systems that run the gamut from Loran-C (0.25 - 5 nm accuracy) to differential GPS (1 m accuracy). Despite the varying sounding and navigation techniques upon which they are based, all of the NOS soundings used in constructing the Coastal Relief Model meet rigorous standards for accuracy. The same standards are employed by the International Hydrographic Office and have remained relatively consistent since the 1800's. The vertical accuracy of the soundings The horizontal accuracy of the soundings is generally 30 m, but it can vary from as fine as 15 m in ports and estuaries to as coarse as 75 m in the offshore areas. Differential GPS has improved this level of accuracy considerably for the most recent survey data.
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    These data are complete (see: http://www.ngdc.noaa.gov/mgg/coastal/model.html)
  5. How consistent are the relationships among the observations, including topology?
    Land elevations within the gridded dataset come from the United States Geological Survey/ National Image Mapping Agency (USGS/NIMA) 1:250,000 or 1 degree DEMs of the states. A description of the USGS/NIMA DEMs and how they were derived can be accessed on the World Wide Web at http://edcwww.cr.usgs.gov/glis/hyper/guide/1_dgr_dem (this online link is no longer valid). Our focus, however, is on the bathymetric soundings that are used in constructing the offshore regions of the grids. Soundings for each volume of the Coastal Relief model series are compiled from hydrographic surveys conducted by the National Ocean Service (NOS) and from various academic institutions. The surveys were carried out using a variety of sounding methods including SeaBeam 16-beam, 12-kHz swath mapping system (6000- >3000m operating water depths), General Instruments 17-beam, 36-kHz Hydrochart II swath mapping system (5-150m operating water depths), single-beam echosounder (e.g., 3.5 kHz narrow 2 degree beam), and lead-line sounding method. These latter surveys date as far back as the late 1800's. A wide range of navigation methods are also associated with the surveys. Visual navigation is based on three-point sextant fixes, theodolite intersections, and celestial fixes. Electronic navigation involves short to long range positioning systems that run the gamut from Loran-C (0.25 - 5 nm accuracy) to differential GPS (1 m accuracy). Despite the varying sounding and navigation techniques upon which they are based, all of the NOS soundings used in constructing the Coastal Relief Model meet rigorous standards for accuracy. The same standards are employed by the International Hydrographic Office and have remained relatively consistent since the 1800's. The vertical accuracy of the soundings is 0.3 m in 0 - 20 m of water, 1.0 m in 20 - 100 m of water, and 1% of the water depth in 100 m of water. The horizontal accuracy of the soundings is within a radius of 1.5 mm of the sounding location at the scale at which the soundings are recorded. NOS surveys are plotted at map scales that range from 1:10,000 for harbors and channels to 1:50,000 for open ocean surveys, with 1:20,000 being the most commonly used scale. The horizontal accuracy of the soundings is generally 30 m, but it can vary from as fine as 15 m in ports and estuaries to as coarse as 75 m in the offshore areas. Differential GPS has improved this level of accuracy considerably for the most recent survey data. While the NOS soundings collected since 1965 have been recorded digitally, those collected prior to this time were recorded manually and then used to make hand-drawn bathymetric maps. Approximately 1,550 of these hand-drawn bathymetric maps have been digitized and assimilated into the NOS Hydrographic Database and, subsequently, were used in constructing the many volumes of the gridded dataset.

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 is freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of this dataset.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    (508) 548-8700 (voice)
    (580) 457-2310 (FAX)
  2. What's the catalog number I need to order this data set? Downloadable Data: 10 meter contours (ESRI Shapefile) for the Gulf of Farallones region
  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 importing the 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: 11-Nov-2021
Metadata author:
Edward M. Sweeney
U.S. Geological Survey
Research Assistant
384 Woods Hole Rd.
Woods Hole, MA
USA

(508) 548-8700 (voice)
(508) 457-2310 (FAX)
whsc_data_contact@usgs.gov
Contact_Instructions:
The metadata contact email address is a generic address in the event the metadata contact is no longer with the USGS
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/open_file_report/ofr2004-1082/10mContour.shp.faq.html>
Generated by mp version 2.9.50 on Mon Nov 15 14:24:34 2021