Beach topography of the Columbia River littoral cell, Washington and Oregon, 2021

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Frequently anticipated questions:


What does this data set describe?

Title:
Beach topography of the Columbia River littoral cell, Washington and Oregon, 2021
Abstract:
This portion of the USGS data release presents topography data collected during surveys performed in the Columbia River littoral cell, Washington and Oregon, in 2021 (USGS Field Activity Number 2021-632-FA). Topographic profiles were collected by walking along survey lines with global navigation satellite system (GNSS) receivers mounted on backpacks. Prior to data collection, vertical distances between the GNSS antennas and the ground were measured using a tape measure. Hand-held data collectors were used to log raw data and display navigational information allowing surveyors to navigate survey lines spaced at 100- to 1000-m intervals along the beach. Profiles were surveyed from the landward edge of the study area (either the base of a bluff, engineering structure, or just landward of the primary dune) over the beach foreshore, to wading depth on the same series of transects as nearshore bathymetric surveys that were conducted during the same time period. Additional topographic data were collected between survey lines in some areas with an all-terrain vehicle (ATV) equipped with a GNSS receiver to constrain the elevations and alongshore extent of major morphological features. Positioning data from the survey platforms were referenced to a GNSS base station with known horizontal and vertical coordinates relative to the North American Datum of 1983. Differential corrections from the GNSS base stations to the survey platforms were either applied in real-time with a VHF radio link, or post-processed using Trimble Business Center software. Orthometric elevations relative to the NAVD88 vertical datum were computed using National Geodetic Survey Geoid12a offsets. The average estimated vertical uncertainty of the topographic measurements is 4 cm. The final point data are provided in comma-separated text format and are projected in Cartesian coordinates using the Washington State Plane South, meters coordinate system.
Supplemental_Information:
Additional information about the field activities from which these data were derived are available online at:
https://cmgds.marine.usgs.gov/fan_info.php?fan=2021-632-FA
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  1. How might this data set be cited?
    Stevens, Andrew W., Weiner, Heather M., and Kaminsky, George M., 20211201, Beach topography of the Columbia River littoral cell, Washington and Oregon, 2021: data release DOI:10.5066/P9W15JX8, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Stevens, Andrew W., Weiner, Heather M., Wood, Jeffrey M., Ruggiero, Peter R., Kaminsky, George M., and Gelfenbaum, Guy R., 2019, Beach topography and nearshore bathymetry of the Columbia River littoral cell, Washington and Oregon (ver. 3.0, November 2021): data release DOI:10.5066/P9W15JX8, U.S. Geological Survey, Santa Cruz, CA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -124.1886811
    East_Bounding_Coordinate: -123.9483169
    North_Bounding_Coordinate: 47.1160087
    South_Bounding_Coordinate: 46.1165352
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 22-Jul-2021
    Ending_Date: 27-Jul-2021
    Currentness_Reference:
    ground condition at time data were collected
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: comma-delimited text
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point (284696)
    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 0.0000001. Longitudes are given to the nearest 0.0000001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is GRS_1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257222101.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: North American Vertical Datum of 1988
      Altitude_Resolution: 0.01
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    Attribute Table
    Table containing attribute information associated with the dataset (Source: Producer defined)
    area
    Designation of sub-area within the Columbia River littoral cell survey area (Source: producer defined)
    ValueDefinition
    ClatsopClatsop sub-area
    Long BeachLong Beach sub-area
    GraylandGrayland sub-area
    North BeachNorth Beach sub-area
    line_number
    Numeric code identifying the number of the survey line. Data that were not collected along a survey line are labeled "None". (Source: Producer defined)
    Range of values
    Minimum:001
    Maximum:221
    datetime_utc
    The date and time of data collection in Coordinated Universal Time (UTC). (Source: Producer Defined)
    Range of values
    Minimum:2021-Jul-22 12:49:24.000
    Maximum:2021-Jul-27 18:26:48.000
    Units:date and time in yyyy-mmm-dd HH:MM:SS.FFF format
    longitude
    Longitude coordinate of data point relative to the North American Datum of 1983 (Source: Producer defined)
    Range of values
    Minimum:-124.1886811
    Maximum:-123.9483169
    Units:Decimal degrees
    latitude
    Latitude coordinate of data point relative to the North American Datum of 1983 (Source: Producer defined)
    Range of values
    Minimum:46.1165352
    Maximum:47.1160087
    Units:Decimal degrees
    easting_m
    East coordinate of data point relative to the North American Datum of 1983, projected in the Washington State Plane South, meters, coordinate system (Source: Producer defined)
    Range of values
    Minimum:220036.92
    Maximum:233558.05
    Units:meters
    northing_m
    North coordinate of data point relative to the North American Datum of 1983, projected in the Washington State Plane South, meters, coordinate system (Source: Producer defined)
    Range of values
    Minimum:92894.44
    Maximum:204679.98
    Units:meters
    distance_m
    Distance from reference point along planned survey line. Distances are relative to an arbitrary reference point. Depending on the orientation of the target line and position of the reference point, the along-line distance can be positive or negative in any direction. NaN=not a number, because the data were not collected along a pre-defined survey line. (Source: Producer defined)
    Range of values
    Minimum:-1187.47
    Maximum:49.95
    Units:meters
    offline_m
    Horizontal distance from planned survey line. Depending on the orientation of the target line and position of the reference point, the offline distance can be positive or negative in any direction. NaN=not a number, because the data were not collected along a pre-defined survey line. (Source: Producer defined)
    Range of values
    Minimum:-3.00
    Maximum:3.00
    Units:meters
    ellipsoid_ht_m
    Height in meters of data point with reference to the reference ellipsoid (Source: Producer defined)
    Range of values
    Minimum:-26.64
    Maximum:-6.75
    Units:meters
    ortho_ht_m
    Height in meters of data point with reference to the North American Vertical Datum of 1988. (Source: Producer defined)
    Range of values
    Minimum:-2.23
    Maximum:17.14
    Units:meters

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Andrew W. Stevens
    • Heather M. Weiner
    • George M. Kaminsky
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    PCMSC Science Data Coordinator
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    2885 Mission St.
    Santa Cruz, CA

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

Why was the data set created?

Data were obtained to document interannual changes in shoreline position and coastal morphology. 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 topographic and shallow-water 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: 27-Jul-2021 (process 1 of 3)
    Topographic profiles were collected on foot with GNSS receivers mounted on backpacks. Prior to data collection, vertical distances between the GNSS antennas and the ground were measured using a tape measure. Hand-held data collectors were used to log raw data and display navigational information allowing surveyors to navigate survey lines spaced at 100- to 1,000-m intervals along the beach. Profiles were surveyed from the landward edge of the study area (either the base of a bluff, engineering structure, or just landward of the primary dune) over the beach foreshore, to wading depth on the same series of transects as nearshore bathymetric surveys that were conducted during the same time period. Additional topographic data were collected between survey lines in some areas with an all-terrain vehicle (ATV) to constrain the elevations and alongshore extent of major morphological features. Raw GNSS data were logged at a measured height above the ground as the ATV traversed the beach.
    Date: 26-Aug-2021 (process 2 of 3)
    Positioning data from the survey platforms that were collected in autonomous mode were post-processed to apply differential corrections from a GNSS base station with known horizontal and vertical coordinates relative to the North American Datum of 1983. Post-processing of raw GNSS data was performed with Trimble Business Center. Orthometric elevations relative to the NAVD88 vertical datum were computed using National Geodetic Survey Geoid12a offsets. The final point data from the topographic surveyors are also projected in cartesian coordinates using the Washington State Plane South, meters coordinate system.
    Date: 26-Aug-2021 (process 3 of 3)
    All available topography data from the survey were compiled into a comma-delimited text file for distribution
  3. What similar or related data should the user be aware of?
    Daniels, Richard C., Ruggiero, Peter, and Weber, Leonard E., 1999, Washington Coastal Geodetic Control Network: Report and Station Index: Washington State Department of Ecology Publication #99-103, Olympia, WA.


How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    No formal attribute accuracy tests were conducted.
  2. How accurate are the geographic locations?
    Survey-grade positions of the rovers were achieved with global navigation satellite system (GNSS) receivers and a single GNSS base station placed on a benchmark with published horizontal coordinates relative to the North American Datum of 1983 (Daniels and others, 1999). The horizontal positions of the geodetic reference network meet first-order specifications established by the National Geodetic Survey with a horizontal accuracy of 2 cm or better. Differential corrections from the GNSS base stations to the rovers were either applied in real-time with a VHF radio link, or post-processed using Trimble Business Center software. Manufacturer reported accuracy for the differentially corrected horizontal positions for the GNSS rover trajectories is 0.8 cm + 0.5 ppm. Baselines from the GNSS base station varied between 300 m and 12 km with a mean of 3.5 km, suggesting the average horizontal accuracy of rover positions to be about 1 cm. Combining the uncertainty in the benchmark and rover yields a total uncertainty of 3 cm. Uncertainty in the horizontal positions associated with sinking into the substrate or variable posture during data collection of the surveyors is unknown.
  3. How accurate are the heights or depths?
    The vertical positions of the geodetic reference network meet 2 cm local ellipsoid height specifications established by the National Geodetic Survey (Daniels and others, 1999). Manufacturer reported accuracy for the differentially corrected vertical positions for the GNSS rover trajectories is 1.5 cm + 1 ppm. Baselines from the GNSS base station varied between 300 m and 12 km with a mean of 3.2 km, suggesting the average vertical accuracy of the survey platforms to be about 1.8 cm relative to the benchmark elevation. Combining the uncertainty in the base station elevation (2 cm) and rover positions yields a total estimated vertical uncertainty of 3.8 cm. Uncertainty in the vertical positions associated with sinking into the substrate or variable posture during data collection of the surveyors is unknown.
  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?
    All data falls within expected ranges.

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? Topographic data are available as a comma-delimited text file (crlc21_topo.csv), along with associated FGDC-compliant metadata.
  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: 01-Dec-2021
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: PCMSC Science Data Coordinator
2885 Mission St.
Santa Cruz, CA

831-427-4747 (voice)
pcmsc_data@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/pcmsc/DataReleases/ScienceBase/DR_P9W15JX8/crlc21_topo_metadata.faq.html>
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