Geologic character of the inner San Pedro Shelf seafloor, southern California (inner_shelf_character.tif)

Frequently anticipated questions:

What does this data set describe?

Title:
Geologic character of the inner San Pedro Shelf seafloor, southern California (inner_shelf_character.tif)
Abstract:
INNER_SHELF_CHARACTER.TIF is a raster image showing seafloor geologic character of the inner San Pedro shelf, southern California, as interpreted from sonar images, multibeam bathymetry, seafloor video and photos, and from sediment sampling. Data resolutions is 4m. The outer part of the shelf is mapped in an accompanying dataset outer_shelf_character.img with a resolution of 16m.
This data set is one of a collection of digital files of a geographic information system (GIS) of spatially referenced data related to the study of seafloor geology and benthic habitats of the San Pedro shelf off southern California.
The San Pedro shelf study area covers approximately 400 sq km offshore of the metropolitan Los Angeles area out to a water depth of about 150 m (492 ft). The seafloor hosts a rich and varied biologic community and is subject to anthropogenic inputs from shipping traffic, sewage outfall systems, commercial fisheries, and recreational use. Between 1998 and 2004, the U.S. Geological Survey (in cooperation with Los Angeles and Orange County Sanitation Districts) mapped the seafloor with sonar technologies, collected video and still photography, and collected sediment samples to develop a characterization of this shelf area.
Supplemental_Information:
Information for USGS Coastal and Marine Geology related activities are online at 
 <http://walrus.wr.usgs.gov/infobank/a/a398sc/html/a-3-98-sc.meta.html>
 <http://walrus.wr.usgs.gov/infobank/c/c199sc/html/c-1-99-sc.meta.html>
 <http://walrus.wr.usgs.gov/infobank/o/o104sc/html/o-1-04-sc.meta.html>
 <http://walrus.wr.usgs.gov/infobank/e/e204sc/html/e-2-04-sc.meta.html>
  1. How should this data set be cited?

    United States Geological Survey (USGS), Dartnell, Peter, and Edwards, Brian, 2012, Geologic character of the inner San Pedro Shelf seafloor, southern California (inner_shelf_character.tif):.

    Online Links:

    This is part of the following larger work.

    Wong, Florence L. , Edwards, Brian D. , Dartnell, Peter, and Phillips, Eleyne L. , 2012, Seafloor Geology and Benthic Habitats of the San Pedro shelf, southern California: U.S. Geological Survey Digital Series 552, U.S. Geological Survey, Menlo Park, California.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -118.33813
    East_Bounding_Coordinate: -117.95043
    North_Bounding_Coordinate: 33.71202
    South_Bounding_Coordinate: 33.56497

  3. What does it look like?

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

    Calendar_Date: 2004
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form:
    ERDAS Imagine (.img) and TIFF image

  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 5189 x 12406 x 1, type Pixel

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

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 11
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -117.000000
      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 4.0
      Ordinates (y-coordinates) are specified to the nearest 4.0
      Planar coordinates are specified in Meters

      The horizontal datum used is WGS84.
      The ellipsoid used is WGS84.
      The semi-major axis of the ellipsoid used is 6378137.00 meters.
      The flattening of the ellipsoid used is 1/0.003352811.

  7. How does the data set describe geographic features?

    facies_innershelf.img.vat
    raster value attribute table (Source: ERDAS)

    OID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Value
    internal sequence number (Source: ERDAS Imagine)

    Sequential unique whole numbers that are automatically generated.

    Class_name
    assigned character description (Source: this study.)

    Descriptive name assigned to seafloor characteristics: undefined; rugose rock; sand; mixed rock, sand; muddy sand; coarser sand, shell material.

    Red
    red component of RGB value for pixel (Source: ERDAS Imagine)

    Range of values
    Minimum:0
    Maximum:1

    Green
    red component of RGB value for pixel (Source: ERDAS Imagine)

    Range of values
    Minimum:0
    Maximum:1

    Blue
    blue component of RGB value for pixel (Source: ERDAS Imagine)

    Range of values
    Minimum:0
    Maximum:1

    Opacity
    Opacity (Source: ERDAS Imagine)

    ValueDefinition
    0not opaque
    1opaque

    Hypothesis
    numeric value applied to Class_name (Source: this study)

    Descriptive name assigned to seafloor characteristics: 0 undefined; 1 rugose rock; 2 sand; 3 mixed rock, sand; 4 muddy sand; 5 coarser sand, shell material.

    Count
    Pixel count in category (Source: ERDAS Imagine)

    pixel count of class or category

    Entity_and_Attribute_Overview:
    Facies_innershelf.img is an ERDAS Imagine image with the following attributes:
    red: rock or high relief beige: sand yellow: coarse, clean sand green: muddy sand
    Entity_and_Attribute_Detail_Citation: This study.

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?

    Peter Dartnell
    United States Geological Survey (USGS) Coastal and Marine Geology (CMG)
    Physical Scientist
    USGS, MailStop 999, 345 Middlefield Road
    Menlo Park, CA 94025-3561
    USA

    (650) 329-5460 (voice)
    (650) 329-5411 (FAX)
    pdartnell@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 the seafloor character map of the San Pedro Shelf, southern California.

How was the data set created?

  1. From what previous works were the data drawn?

    Gardner and others, 1999 (source 1 of 4)
    Gardner, J.V., Hughes-Clarke, J.E., and Mayer, L.A., 1999, Cruise Report: RV Coastal Suveryor Cruise C-1-99-SC, Multibeam Mapping of the Long Beach, California, Continental Shelf.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution: data collection methods and data

    Gardner and Mayer, 1998 (source 2 of 4)
    Gardner, J.V., and Mayer, L.A., 1998, Cruise Report: RV Ocean Alert Cruise A2-98-SC, Mapping the Southern California Continental Margin.

    Online Links:

    Other_Citation_Details: Cruise ID should be A-3-98-SC not, A-2-98-SC
    Type_of_Source_Media: online
    Source_Contribution: data collection methods and data

    Dartnell and Gardner, 2004a (source 3 of 4)
    Dartnell, P., and Gardner, J.V., 2004, Predicting seafloor facies from multibeam bathymetry and backscatter data: Photogrammetric Engineering and Remote Sensing Vol. 70, No.9, pp 1081-1091.

    Type_of_Source_Media: online
    Source_Contribution: methods description

    Dartnell and Gardner, 2004b (source 4 of 4)
    Dartnell, P., and Gardner, J.V., 2004, Predicted Seafloor Facies of Central Santa Monica Bay, California: USGS Open-File Report 2004-1081.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution: methods description

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

    Date: 1998 (process 1 of 4)
    The San Pedro shelf was mapped over a two-year period using two different multibeam echo-sounding systems (MBES). In 1998, the outer mainland shelf and slope were mapped using a Kongsberg EM300 MBES (30kHz) (A-3-98-SC; Gardner and others, 1998).
    In 1999, the inner mainland shelf from the Palos Verdes Peninsula south to Dana Point was mapped using a Kongsberg EM3000D MBES (300kHz) (C-1-99-SC; Gardner and others, 1999; Dartnell and Gardner, 2004a, 2004b).

    Date: 2004 (process 2 of 4)
    In October 2004, 365 line kilometers of sea floor video and over 13,000 photographs were collected over the entire shelf (O-1-04-SC) and in December 2004, 182 sediment samples were collected over the shelf (E-2-04-SC).

    Date: 2005 (process 3 of 4)
    A hierarchical decision-tree classification scheme (ERDAS Imagine) was used to classify the multibeam bathymetry and backscatter data into a seafloor character map - rock or hardground, bioturbated sand, sand with bedforms and shell hash, bioturbated muddy sand, and bioturbated sandy mud. Seafloor video, photographs, real-time observations, and the sediment textural data were all used to develop, test, and refine rules in the hierarchical decision-tree classification scheme. The final interpreted map was saved and exported into the Imagine (.img) and TIFF (.tif) formats available in this report.

    Person who carried out this activity:

    Peter Dartnell
    United States Geological Survey (USGS) Coastal and Marine Geology (CMG)
    Physical Scientist
    USGS, MailStop 999, 345 Middlefield Road
    Menlo Park, CA 94025-3561
    USA

    (650) 329-5460 (voice)
    (650) 329-5411 (FAX)
    pdartnell@usgs.gov

    Date: 27-Aug-2012 (process 4 of 4)
    Metadata imported.

    Data sources used in this process:

    • d:\temp\xml2B0.tmp

  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?

    Not applicable for raster data.

  2. How accurate are the geographic locations?

    4 meters

  3. How accurate are the heights or depths?

    0.05 percent of the water depth. Depths corrected to mean lower low water datum.

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

    Complete

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

    Unspecified

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) 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)

    United States Geological Survey (USGS) Information Services
    345 Middlefield Rd., MS-999
    Menlo Park, CA 94025
    USA

    (650)329-5460 (voice)

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

    Downloadable Data

  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, USDOI, 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: 2012
Last Reviewed: 2010
Metadata author:
United States Geological Survey (USGS) Coastal and Marine Geology (CMG)
Attn: Florence Wong
Geologist
USGS, MailStop 999, 345 Middlefield Road
Menlo Park, CA 94025-3561
USA

(650) 329-5327 (voice)
fwong@usgs.gov

Metadata standard:
Content Standard for Digital Geospatial Metadata ("CSDGM version 2") (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.9.15 on Mon Aug 27 10:19:13 2012