Habitat--Offshore of Bodega Head, California

Frequently anticipated questions:

What does this data set describe?

Title: Habitat--Offshore of Bodega Head, California
Abstract:
This part of DS 781 presents data for the habitat map of the seafloor of the Offshore of Bodega Head map area, California. The vector data file is included in "Habitat_OffshoreBodegaHead.zip," which is accessible from https://pubs.usgs.gov/ds/781/OffshoreBodegaHead/data_catalog_OffshoreBodegaHead.html. These data accompany the pamphlet and map sheets of Johnson, S.Y., Dartnell, P., Golden, N.E., Hartwell, S.R., Erdey, M.D., Greene, H.G., Cochrane, G.R., Kvitek, R.G., Manson, M.W., Endris, C.A., Dieter, B.E., Watt, J.T., Krigsman, L.M., Sliter, R.W., Lowe, E.N., and Chin, J.L. (S.Y. Johnson and S.A. Cochran, eds.), 2015, California State Waters Map Series—Offshore of Bodega Head, California: U.S. Geological Survey Open-File Report 2015–1140, pamphlet 39 p., 10 sheets, scale 1:24,000, https://doi.org/10.3133/ofr20151140.
Potential marine benthic habitat maps were constructed using multibeam echosounder (MBES) bathymetry and backscatter data. The habitats were based on substrate types and documented or "ground truthed" using underwater video images and seafloor samples obtained by the USGS. These maps display various habitat types that range from flat, soft, unconsolidated sediment-covered seafloor to hard, deformed (folded), or highly rugose and differentially eroded bedrock exposures.
Supplemental_Information:
References Cited:
Greene, H.G., Bizzarro, J.J., O'Connell, V.M., and Brylinsky, C.K., 2007, Construction of digital potential marine benthic habitat maps using a coded classification scheme and its application, in Todd, B.J., and Greene, H.G., eds., Mapping the seafloor for habitat characterization: Geological Association of Canada Special Paper 47, p. 141-155.
Greene, H.G., Yoklavich, M.M., Starr, R.M., O'Connell, V.M., Wakefield, W.W., Sullivan, D.E., McRea, J.E., Jr., and Cailliet, G.M., 1999, A classification scheme for deep seafloor habitats: Oceanologica Acta, v. 22, no. 6, p. 663-678.
Additional information about the field activity from which these data were derived is available online at:
https://cmgds.marine.usgs.gov/fan_info.php?fan=l908NC
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in Esri format, this metadata file may include some Esri-specific terminology.
  1. How might this data set be cited?
    Dieter, Bryan E., Greene, H. Gary, and Endris, Charles A., 2014, Habitat--Offshore of Bodega Head, California: Data Series DS 781, U.S. Geological Survey, Reston, VA.

    Online Links:

    This is part of the following larger work.

    Golden, Nadine E., 2013, California State Waters Map Series Data Catalog: Data Series DS 781, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -123.17
    East_Bounding_Coordinate: -122.97
    North_Bounding_Coordinate: 38.41
    South_Bounding_Coordinate: 38.25
  3. What does it look like?
    https://pubs.usgs.gov/ds/781/OffshoreBodegaHead/images/Habitat_OffshoreBodegaHead.jpg (JPEG)
    Benthic habitat offshore Bodega Head.
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2014
    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):
      • GT-polygon composed of chains (963)
    2. What coordinate system is used to represent geographic features?
      The map projection used is WGS 1984 UTM Zone 10N.
      Projection parameters:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -123.0
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000.0
      False_Northing: 0.0
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 2
      Ordinates (y-coordinates) are specified to the nearest 2
      Planar coordinates are specified in Meter
      The horizontal datum used is D WGS 1984.
      The ellipsoid used is WGS 1984.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257223563.
  7. How does the data set describe geographic features?
    Habitat_OffshoreBodegaHead
    Polygons representing habitat map units (Source: This report)
    OBJECTID
    Internal feature number. (Source: ESRI) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: ESRI) Coordinates defining the features.
    Hab_Code
    Habitat code (Source: Center for Habitat Studies, Greene and others (1999, 2007)) Names are in text form, maximum length: 25
    Hab_Type
    Habitat type (Source: Center for Habitat Studies, Greene and others (1999, 2007)) Names are in text form, maximum length: 100
    Mega_ID
    Megahabitat ID code (Source: Center for Habitat Studies, Greene and others (1999, 2007)) Names are in text form, maximum length: 10
    Mega
    Megahabitat description (Source: Center for Habitat Studies, Greene and others (1999, 2007)) Names are in text form, maximum length: 35
    Ind_ID
    Seafloor induration ID code (Source: Center for Habitat Studies, Greene and others (1999, 2007)) Names are in text form, maximum length: 10
    Ind
    Seafloor induration description (Source: Center for Habitat Studies, Greene and others (1999, 2007)) Names are in text form, maximum length: 35
    Sed_ID
    Sediment ID code (Source: Center for Habitat Studies, Greene and others (1999, 2007)) Names are in text form, maximum length: 10
    Sed
    Sediment description (Source: Center for Habitat Studies, Greene and others (1999, 2007)) Names are in text form, maximum length: 35
    Mes_Mac_ID
    Meso/Macro-habitat ID code (Source: Center for Habitat Studies, Greene and others (1999, 2007)) Names are in text form, maximum length: 15
    Mes_Mac
    Meso/Macro-habitat description (Source: Center for Habitat Studies, Greene and others (1999, 2007)) Names are in text form, maximum length: 50
    Mod_ID
    Habitat modifier ID code (Source: Center for Habitat Studies, Greene and others (1999, 2007)) Names are in text form, maximum length: 15
    Mod
    Habitat modifier description (Source: Center for Habitat Studies, Greene and others (1999, 2007)) Names are in text form, maximum length: 50
    Hab_Desc
    Habitat Description (Source: Center for Habitat Studies, Greene and others (1999, 2007)) Names are in text form, maximum length: 200
    Area
    Polygon area in meters (Source: ESRI Calculate Geometry (Area in square meters) tool)
    Range of values
    Minimum:34.819099
    Maximum:62299230.1744
    Units:Float values in square meters

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, Pacific Coastal and Marine Science Center
    Attn: PCMSC Science Data Coordinator
    2885 Mission Street
    Santa Cruz, CA
    US

    831-427-4747 (voice)
    pcmsc_data@usgs.gov

Why was the data set created?

To expand geologic mapping to the seafloor within the California's State Waters, to update coastal geologic mapping, and to contribute to a uniform regional geologic database, which can be used geographic information systems. Additionally, to provide a geologic map for the public and geoscience community to aid in assessments and mitigation of geologic hazards in the Drakes Bay coastal region and to provide sufficient geologic information for land-use and land-management decisions both onshore and offshore. This information is not intended for navigational purposes.

How was the data set created?

  1. From what previous works were the data drawn?
    bathymetry (source 1 of 3)
    Dartnell, Peter, and Kvitek, Rikk G., 2014, Bathymetry--Offshore of Bodega Head, California: Data Series DS 781, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    See metadata for bathymetry ("Bathymetry_OffshoreBodegaHead_metadata.txt") in DS 781 for source data and postprocessing/reprocessing information.
    Type_of_Source_Media: digital file of gridded bathymetry data (ArcInfo GRID)
    Source_Contribution: Gridded bathymetry data (2-meter resolution)
    backscatter (source 2 of 3)
    Dartnell, Peter, and Kvitek, Rikk G., 2014, Backscatter--Offshore of Bodega Head, California: Data Series DS 781, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    See metadata for backscatter datasets ("BackscatterA_8101_OffshoreBodegaHead_metadata.txt", "BackscatterB_7125_OffshoreBodegaHead_metadata.txt" and "BackscatterC_Swath_OffshoreBodegaHead.txt") in DS 781 for amplitude source data and postprocessing/reprocessing information.
    Type_of_Source_Media: digital file of gridded amplitude data (ArcInfo GRID)
    Source_Contribution: Gridded backscatter amplitude data (2-meter resolution)
    imagery (source 3 of 3)
    Edwards, Brian, Phillips, Eleyne, Golden, Nadine, Krigsman, Lisa, and Dartnell, Pete, 2014, L908NC_video_observations: Data Series DS 781, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    See metadata for L0908NC video observations ("l908nc_video_observations_metadata.txt") in DS 781 for source data and postprocessing/reprocessing information.
    Type_of_Source_Media: vector digital data
    Source_Contribution:
    seafloor interpretations from underwater video and sediment samples
  2. How were the data generated, processed, and modified?
    Date: 2014 (process 1 of 6)
    Data used for the creation of the potential marine benthic habitat interpretation consists of multibeam bathymetry, acoustic backscatter, sediment samples, camera-sled imagery, and existing geologic and seafloor interpretive maps. All data were compiled and displayed for interpretation using ESRI ArcGIS software, ArcMap v.10.0. The process consists of editing a shapefile within ArcMap, beginning with the construction of polygons to delineate benthic features. A benthic feature is an area with common characteristics which can be characterized as a single potential habitat type. The boundaries and extents of these features were determined from the bathymetric data. In general, interpretations were made at scales between 1:2,000 and 1:5,000. The USGS kindly provided the Center for Habitat Studies with a geodatabase consisting of feature datasets delineating geologic features and attributes for Drakes Bay and vicinity. Some of the delineated polygons were preserved as part of the potential marine benthic habitat characterization. However, the Greene and others (2007) code was used in attributing the dataset and additional polygons were added using the methods outlined below. High-resolution multibeam sonar data in the form of bathymetric depth grids (seafloor digital elevation models, referred to as the "bathymetry") were the primary data used in the interpretation of potential habitat types. Shaded-relief imagery ("hillshade") allows for visualization of the terrain and interpretation of submarine landforms. On the basis of these hillshades, areas of rock were identified by their often sharply defined edges and high relative relief; these may be contiguous outcrops, isolated parts of outcrop protruding through sediment cover (pinnacles), or isolated boulders. Although these types of features can be confidently characterized as exposed rock, it is not uncommon to find areas within or around the rocky feature that appear to be covered by a thin veneer of sediment. These areas are identified as "mixed" induration, containing both rock and sediment. Broad areas of the seafloor lacking sharp and angular characteristics are considered to be sediment. Sedimentary features may contain erosional or depositional characteristics recognizable in the bathymetry, such as dynamic bedforms (dunes or sand waves). General morphologic features such as scours, mounds, and depressions were also identified using the hillshade imagery. The combination of acoustic backscatter data and "ground truthed" sediment samples were used to delineate seafloor sediment types within areas identified as "soft (s)" induration. Initially, ground truth data, in the form of grab sample descriptions and average grain size measurements, were categorized into four grain-size categories: mud (m), muddy sand (s/m), sand (s), and sandy gravel (s/g). Backscatter data was then classified into four intensity categories (low, med, high, very high) that are assumed to correspond to relative grain sizes. The aim was to develop an intensity classification of the seafloor that correlated with the data collected from the sediment samples. Thus, the combination of remotely observed data (acoustic backscatter) and directly observed data (sediment grab samples) translates to higher confidence in our ability to interpret broad areas of the seafloor. Nonetheless, we caution against using our sediment type interpretations as anything more than "best-guess" because of the following issues: characterization of contiguous sediment bodies is a difficult procedure because even small areas can exhibit a wide spectrum of backscatter-intensity values that lack distinct boundaries; backscatter intensity can be affected by depth, vegetation, water column conditions, and seafloor relief; and directly observed sediment data, in the form of sediment samples, represents a very small area relative to remotely observed data, requiring broad areas of interpolation. Data sources used in this process:
    • bathymetry
    • backscatter
    • imagery
    Date: 05-Oct-2017 (process 2 of 6)
    Added Distribution_Information section to metadata to facilitate data download. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alan O. Allwardt
    Contractor -- Information Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7551 (voice)
    831-427-4748 (FAX)
    aallwardt@usgs.gov
    Date: 05-Oct-2017 (process 3 of 6)
    Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alan O. Allwardt
    Contractor -- Information Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7551 (voice)
    831-427-4748 (FAX)
    aallwardt@usgs.gov
    Date: 26-Apr-2018 (process 4 of 6)
    Added keywords from Coastal and Marine Ecological Classification Standard (CMECS) to metadata. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alan O. Allwardt
    Contractor -- Information Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7551 (voice)
    831-427-4748 (FAX)
    aallwardt@usgs.gov
    Date: 19-Oct-2020 (process 5 of 6)
    Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed. 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: 25-Jul-2022 (process 6 of 6)
    Edited metadata to fix validation errors and to bring it up to FGDC CSDGM current standards based on data release policies for USGS Coastal and Marine Hazards and Resources Program (CMHRP). No data were changed. The metadata available from a harvester may supersede metadata bundled within a download file. Users are advised to compare the metadata dates to determine which metadata file is most recent. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Susan Cochran
    Geologist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7545 (voice)
    scochran@usgs.gov
  3. What similar or related data should the user be aware of?
    Johnson, S.Y., Dartnell, P., Golden, N.E., Hartwell, S.R., Erdey, M.D., Greene, H.G., Cochrane, G.R., Kvitek, R.G., Manson, M.W., Endris, C.A., Dieter, B.E., Watt, J.T., Krisgman, L.M., Sliter, R.W., Lowe, E.N., and Chin, J.L., 2015, California State Waters Map Series--Offshore of Bodega Head, California: Open-File Report 2015-1140, U.S. Geological Survey, Reston, VA.

    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?
    Interpretation and polygon delineation of habitats performed at scales from 1:2000 to 1:5000
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    Contact authors for information about omissions, selection criteria, generalization, definitions used, and other rules used to derive the data set.
  5. How consistent are the relationships among the observations, including topology?
    Map elements were visually checked for overshoots, undershoots, duplicate features, polygon closure, and other errors by the lead authors and by the GIS technician(s) who created the digital database. Review drafts of the map were reviewed internally by at least two other geologists for consistency with basic geologic principles and general conformity to USGS mapping standards.

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 USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the Center for Habitat Studies, Moss Landing Marine Laboratories, and the U.S. Geological Survey as the originator(s) of the dataset and in products derived from these data. This information is not intended for navigation purposes.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey
    345 Middlefield Rd
    Menlo Park, CA
    USA

    (650) 329-4309 (voice)
  2. What's the catalog number I need to order this data set? The .zip file (Habitat_OffshoreBodegaHead.zip) includes the .aux, .dbf, .shp, .shx, .sbx, and .sbn files, as well as FGDC-compliant metadata for the habitats data layer of Offshore Bodega Head, California.
  3. What legal disclaimers am I supposed to read?
    Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 25-Jul-2022
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: PCMSC Science Data Coordinator
2885 Mission Street
Santa Cruz, CA
US

831-427-4747 (voice)
pcmsc_data@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
Generated by mp version 2.9.52 on Mon Jul 25 22:35:52 2022