Bathymetry from 2013 interferometric swath bathymetry systems survey of Columbia River Mouth, Oregon and Washington

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Frequently anticipated questions:


What does this data set describe?

Title:
Bathymetry from 2013 interferometric swath bathymetry systems survey of Columbia River Mouth, Oregon and Washington
Abstract:
This part of the USGS data release presents bathymetry data for the Columbia River Mouth, Oregon and Washington. The bathymetry data of the Columbia River Mouth, Oregon and Washington were collected by the U.S. Geological Survey (USGS). Mapping was completed in 2013, using a 234-kHz SEA SWATHPlus interferometric system. These data are not intended for navigational purposes.
Supplemental_Information:
Additional information about the field activity from which these data were derived is available online at: http://cmgds.marine.usgs.gov/fan_info.php?fan=S0313WO
  1. How might this data set be cited?
    Gelfenbaum, Guy, Finlayson, David, and Dartnell, Peter, 2015, Bathymetry from 2013 interferometric swath bathymetry systems survey of Columbia River Mouth, Oregon and Washington: data release DOI:10.5066/F7T72FHB, 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.

    Gelfenbaum, Guy, Finlayson, David, and Dartnell, Peter, 2015, Bathymetry and backscatter from 2013 interferometric swath bathymetry systems survey of Columbia River Mouth, Oregon and Washington: data release DOI:10.5066/F7T72FHB, 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: -124.11
    East_Bounding_Coordinate: -123.92
    North_Bounding_Coordinate: 46.29
    South_Bounding_Coordinate: 46.20
  3. What does it look like?
    http://www.sciencebase.gov/catalog/file/get/55de29afe4b0518e354dfd30?name=USGS_CR_bathymetry.png&allowOpen=true (PNG)
    image map showing shaded-relief bathymetry of the Columbia River mouth off Oregon and Washington, color-coded to show depth
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 06-May-2013
    Ending_Date: 18-Jun-2013
    Currentness_Reference:
    ground condition at time data were collected
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: GeoTIFF
  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: 10
      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 1.0
      Ordinates (y-coordinates) are specified to the nearest 1.0
      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 6378137.00 meters.
      The flattening of the ellipsoid used is 1/298.257223563.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: North American Vertical Datum of 1988
      Altitude_Resolution: 0.20
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method: Attribute values
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    The USGS Columbia River Mouth bathymetry data were originally archived as a GeoTIFF image with the following attributes:
    Cell size = 1.0
    Number of rows = 7501
    Number of columns = 15458
    
    Data type = floating point
    
    Boundary
    Xmin = 414118
    Xmax = 429576
    Ymin = 5117602
    Ymax = 5125103
    
    Statistics
    Minimum value = -51.82
    Maximum value = -0.59
    Mean = -14.88
    Standard deviation = 5.82
    
    Coordinate system description
    Projection  UTM
    Zone  10
    Datum  NAD83
    Vertical Datum  NAVD88
    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)
    • Guy Gelfenbaum
    • David Finlayson
    • Peter Dartnell
  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 St.
    Santa Cruz, CA
    USA

    (831) 460-7415 (voice)
    (831) 427-4709 (FAX)
    pdartnell@usgs.gov

Why was the data set created?

These data are intended for science researchers, students, policy makers, and the general public. These data can be used with geographic information systems or other software to identify bathymetric features.

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: 2015 (process 1 of 1)
    The USGS R/V Parke Snavely was equipped with an Applanix Position and Orientation System for Marine Vessels (POS/MV) inertial motion unit (IMU) for the duration of the survey. The POS/MV received Differentially Corrected Global Positioning System (DGPS) aided positional navigation from dual Trimble model 4000 DGPS receivers, and commercial C-Nav satellite differential stations. The DGPS data were combined with the inertial vessel motion measurements (pitch, roll, and heading) directly within the POS/MV hardware so that high-precision position and attitude corrections were fed in real time to the sonar acquisition equipment. Sound velocity measurements were collected continuously with an Applied Micro Systems Micro sound velocimeter (SV) deployed on the transducer frame for real-time sound velocity adjustments at the transducer-water interface. Additionally, water column sound velocity profiles (SVP) were collected approximately every 2 hours throughout each survey day with an Applied Micro Systems, SvPlus 3472. DGPS data and measurements of vessel motion were combined in the POS/MV hardware to produce a high-precision vessel attitude packet. This packet was transmitted to the Swath Processor acquisition software in real time and combined with instantaneous sound velocity measurements at the transducer head before each ping. The returned samples were projected to the seafloor using a ray-tracing algorithm working with the previously measured sound-velocity profiles in SEA Swath Processor. A series of statistical filters were applied to the raw samples that isolated the seafloor returns from other spurious targets in the water column. Finally, the processed data were stored line-by-line in both raw (.sxr) and processed (.sxp) trackline files. Applanix POS/MV records raw inertial and GNSS data while surveying that is later refined through post processing to incorporate publicly available GPS data from nearby base stations. During post processing the POS M/V data is run through POSPac software to produce a Smoothed Best Estimate of Trajectory (SBET) file, which is then used to create new .sxp line files using the Swath Processor software. CARIS HIPS and SIPS bathymetry processing software was used to further clean and bin the raw bathymetry data. Processed .sxp files were imported to CARIS and were filtered to remove obvious erroneous soundings and soundings towards the noisier out beams and then gridded into base surfaces. Base surfaces were exported to ASCIIRaster files and imported into ESRI GIS software. The bathymetry grid was projected horizontally to North American Datum of 1983 (NAD83). The grid was also transformed vertically to the North American Vertical Datum of 1988 (NAVD88) using the GEOID12A model. Note that the USGS collects bathymetric data for scientific purposes only. The USGS does not guarantee that full bottom search has been achieved and the data have not been inspected for dangers to navigation.
  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?
    Horizontal_Positional_Accuracy_Report: Estimated to be no less than 2 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?
    Vertical_Positional_Accuracy_Report: 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?
    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:
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 navigational purposes.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - Science Base
    U.S. Geological Survey
    Denver Federal Center, Building 810, Mail Stop 302
    Denver, CO
    USA

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? Data are available in a zip file (USGS_CR_bathy_UTM10_NAD83_NAVD88.zip) containing a GeoTIFF raster (USGS_CR_bathy_UTM10_NAD83_NAVD88.tif), along with the associated Tiff World File (USGS_CR_bathy_UTM10_NAD83_NAVD8.tfw) and metadata (USGS_CR_bathy_UTM10_NAD83_NAVD88.xml).
  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 TIFF.

Who wrote the metadata?

Dates:
Last modified: 08-Mar-2017
Metadata author:
Peter Dartnell
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Physical Scientist
2885 Mission St.
Santa Cruz, CA
USA

(831) 460-7415 (voice)
(831) 427-4709 (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_CR_bathy_UTM10_NAD83_NAVD88.faq.html>
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