High-resolution multibeam bathymetry data collected in 2004 for the northern Channel Islands region, southern California

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Frequently anticipated questions:


What does this data set describe?

Title:
High-resolution multibeam bathymetry data collected in 2004 for the northern Channel Islands region, southern California
Abstract:
This data release presents data for 5-m resolution multibeam-bathymetry data of the northern Channel Islands region, southern California. The raster data files are included in "USGS_NChannelIslands_NorthArea_Bathy_5m.zip" and "USGS_NChannelIslands_SouthArea_Bathy_5m.zip," which are accessible from https://doi.org/10.5066/F7S46Q1J. In 2004 The U.S. Geological Survey, Pacific Coastal and Marine Science Center collected multibeam-bathymetry and acoustic-backscatter data in the northern Channel Islands region, southern California. The region was mapped aboard the R/V Ewing using a Kongsberg Simrad EM-1002 multibeam echosounder. These data were previously published on-line at http://pubs.usgs.gov/of/2005/1153/. In this data release the data have been reprocessed to a finer spatial resolution (5-m versus 15-m) using more modern processing techniques. Due to the large file sizes the entire survey area is provided as two ASCIIRaster files(USGS_NChannelIslands_NorthArea_Bathy_5m.zip and USGS_NChannelIslands_SouthArea_Bathy_5m.zip).
Supplemental_Information:
Additional information about the field activity from which these data were derived is available online at: http://compass.er.usgs.gov/fan_info.php?fan=E104SC
  1. How might this data set be cited?
    Dartnell, Peter, and Cochrane, Guy R., 2016, High-resolution multibeam bathymetry data collected in 2004 for the northern Channel Islands region, southern California: data release DOI:10.5066/F7S46Q1J, U.S. Geological Survey, Coastal and Marine Geology Program, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Dartnell, Peter, and Cochrane, Guy R., 2016, High-resolution multibeam bathymetry and backscatter data - northern Channel Islands region, southern California: U.S. Geological Survey data release DOI:10.5066/F7S46Q1J, U.S. Geological Survey, Coastal and Marine Geology Program, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -119.70
    East_Bounding_Coordinate: -119.04
    North_Bounding_Coordinate: 34.33
    South_Bounding_Coordinate: 33.86
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 06-Aug-2004
    Ending_Date: 15-Aug-2004
    Currentness_Reference:
    ground condition at the time the data was collected
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: ASCIIRaster
  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, 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: 11
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -123.00000
      Latitude_of_Projection_Origin: 0.00000
      False_Easting: 500000.0
      False_Northing: 0.00
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 5.0
      Ordinates (y-coordinates) are specified to the nearest 5.0
      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.
      The flattening of the ellipsoid used is 1/298.257223563.
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    Due to the large file sizes the entire survey area is provided as two ASCIIRaster files (USGS_NChannelIslands_NorthArea_Bathy_5m.zip and USGS_NChannelIslands_SouthArea_Bathy_5m.zip). The complete 5-m resolution bathymetry grid for the northern region were originally archived as an ESRI grid with the following attributes.
    Cell size = 5.0
    Number of rows = 5344
    Number of columns = 8206
    
    Data type = floating point
    
    Boundary
    Xmin = 251052
    Xmax = 292082
    Ymin = 3774302
    Ymax = 3801022
    
    Statistics
    Minimum value = -250.31
    Maximum value = -20.95
    Mean = -152.83
    Standard deviation = 69.47
    
    Coordinate system description
    Projection  UTM
    Zone  11
    Datum  WGS84
    Vertical Datum  MLLW
    Units  meter
    
    The complete 5-m resolution bathymetry grid for the southern region were originally archived as an ESRI grid with the following attributes.
    Cell size = 5.0
    Number of rows = 4344
    Number of columns = 9630
    
    Data type = floating point
    
    Boundary
    Xmin = 262612
    Xmax = 310762
    Ymin = 3752902
    Ymax = 3774622
    
    Statistics
    Minimum value = -1047.54
    Maximum value = -67.84
    Mean = -465.64
    Standard deviation = 223.47
    
    Coordinate system description
    Projection  UTM
    Zone  11
    Datum  WGS84
    Vertical Datum  MLLW
    Units  meter
    
    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)
    • Peter Dartnell
    • Guy R. Cochrane
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Peter Dartnell
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    Physical Scientist
    2885 Mission Street
    Santa Cruz, CA
    USA

    (831) 460-7415 (voice)
    (831) 427-4748 (FAX)
    pdartnell@usgs.gov

Why was the data set created?

These data are intended for policy makers, resource managers, science researchers, students, and the general public. These data can be used with geographic information systems or other software to identify bathymetric features. These data are not intended to be used for navigation.

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: 30-Nov-2004 (process 1 of 2)
    The multibeam-bathymetry data were collected along a continuous swath perpendicular to the direction of the ship using a Kongsberg Simrad EM1002 multibeam-sonar system. The data were cleaned of bad navigation and depth readings and corrected for tides to mean lower low water datum using a predictive tide model. The depth readings then were gridded into a common grid. The gridded data are converted to ArcInfo GRID format using ArcInfo's ASCIIGRID command.
    Date: 2016 (process 2 of 2)
    The USGS retreived the raw survey line files from the USGS archives. The line files were processed in Caris HIPS and SIPS software (version 9). The data were cleaned of bad navigation and depth readings and corrected for tides to mean lower low water datum using a predictive tide model. The data were gridded into base surfaces with 5-m spatial resolution using the Swath Angle process. Base surfaces then were exported as ASCIIRaster files and imported into a GIS.
  3. What similar or related data should the user be aware of?
    Dartnell, Peter, Cochrane, Guy, and Dunaway, Mary Elaine, 2005, Multibeam bathymetry and backscatter data: northeastern Channel Islands region, southern California: U.S. Geological Survey Open-File Report, Reston, VA.

    Online Links:


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?
    Estimated to be no less than 5 m, owing to water depth and total propagated uncertainties of the mapping systems, which include sonar system, position and motion compensation system, and navigation, as well as data processing that includes sounding cleaning, gridding, and datum transformations.
  3. How accurate are the heights or depths?
    Estimated to be no less than 20 cm, owing to water depth and total propagated uncertainties of the mapping systems, which include sonar system, position and motion compensation system, and navigation, as well as data processing that includes sounding cleaning, gridding, and datum transformations.
  4. Where are the gaps in the data? What is missing?
    Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.
  5. How consistent are the relationships among the observations, including topology?
    No formal logical accuracy tests were conducted

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 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 - ScienceBase
    Denver Federal Center, Building 810, Mail Stop 302
    Denver, CO

    1-888-275-8747 (voice)
    sciencbase@usgs.gov
  2. What's the catalog number I need to order this data set?
  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?
  5. What hardware or software do I need in order to use the data set?
    The downloadable data file has been compressed with the "zip" command and can be unzipped with Winzip (or other tool) on Windows systems. To utilize these data, the user must have software capable of uncompressing the WinZip file and importing and viewing an Esri ArcMap ASCIIRaster.

Who wrote the metadata?

Dates:
Last modified: 03-Mar-2017
Metadata author:
Peter Dartnell
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Physical Scientist
2885 Mission Street
Santa Cruz, CA
USA

(831) 460-7415 (voice)
(831) 427-4748 (FAX)
pdartnell@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/pcmsc/USGS_NChannelIslands_Bathy_5m.faq.html>
Generated by mp version 2.9.49 on Mon Sep 10 17:43:23 2018