Reference baselines used to extract shorelines for the West Coast of the United States

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Frequently anticipated questions:

What does this data set describe?

Title:
Reference baselines used to extract shorelines for the West Coast of the United States
Abstract:
This data release contains reference baselines for primarily open-ocean sandy beaches along the west coast of the United States (California, Oregon and Washington). The slopes were calculated while extracting shoreline position from lidar point cloud data collected between 2002 and 2011. The shoreline positions have been previously published, but the slopes have not. A reference baseline was defined and then evenly-spaced cross-shore beach transects were created. Then all data points within 1 meter of each transect were associated with each transect. Next, it was determined which points were one the foreshore, and then a linear regression was fit through the foreshore points. Beach slope was defined as the slope of the regression. Finally, the regression was evaluated at the elevation of Mean High Water (MHW) to yield the location of the shoreline. In some areas there was more than one lidar survey available; in these areas the slopes from each survey are provided. While most of the slopes are for sandy beaches, there is some slope data from rocky headlands and other steeper beaches. These data files (referenceLine_WestCoast.csv and referenceLine_WestCoast.shp) contain information about the reference baseline, the cross-shore transects, and the Mean High Water values used to estimate the shoreline. The accompanying data files (slopeData_WestCoast.csv and slopeData_WestCoast.shp) contain the slope data. The csv and shapefiles contain the same information, both file types are provided as a convenience to the user.
Supplemental_Information:
The shorelines that were derived when these slopes were calculated can be accessed through the USGS National Shoreline Change Data Catalog: https://www.sciencebase.gov/catalog/item/5b97f1b4e4b0702d0e842183 Note that the transect number used in these publications are different that the transect numbers used here.
  1. How might this data set be cited?
    Farris, Amy S., and Weber, Kathryn M., 20240410, Reference baselines used to extract shorelines for the West Coast of the United States: data release doi:10.5066/P137S83C, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Farris, Amy S., and Weber, Kathryn M., 2024, Beach foreshore slope for the West Coast of the United States: data release doi:10.5066/P137S83C, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    Other_Citation_Details:
    Suggested citation:Farris, A.S., and Weber, K.M., 2024, Beach Foreshore slope for the West Coast of the United States: U.S. Geological Survey data release, https://doi.org/10.5066/P137S83C
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -124.7400
    East_Bounding_Coordinate: -117.1200
    North_Bounding_Coordinate: 48.3500
    South_Bounding_Coordinate: 32.5300
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/65a029b7d34e5af967a38422?name=slope_BrowseGraphic.png&allowOpen=true (PNG)
    Small section of data showing reference baseline and slope data
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 01-Sep-2002
    Ending_Date: 30-Jul-2011
    Currentness_Reference:
    ground condition
  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 Point data set. It contains the following vector data types (SDTS terminology):
      • Point
    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 0.0197394080. Longitudes are given to the nearest 0.0264580536. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is WGS_1984.
      The ellipsoid used is WGS_84.
      The semi-major axis of the ellipsoid used is 6378137.0.
      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: 0.01
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    referenceLine_WestCoast.csv and referenceLine_WestCoast.shp
    The point shapefile file includes information about the reference baseline, cross-shore transects, and Mean High Water (MHW) values used to calculate shorelines for California, Oregon and Washington. A .csv file containing the same fields (except for "FID" and "Shape") is also included. Point object count: 118,072. (Source: USGS)
    FID
    Internal feature number. (Source: ESRI) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: ESRI) Coordinates defining the features.
    State
    Two letter state designation (Source: USGS)
    ValueDefinition
    WAWashington
    OROregon
    CACalifornia
    Region
    Two letter region designation. Oregon and Washington don't have regions. (Source: USGS)
    ValueDefinition
    naNo regions for this state.
    noNorthern California
    ceCentral California
    soSouthern California
    TransNum
    Transect number. Transect numbers are unique for each state, or if the state is divided into regions, for each region. Transect numbers are sequential as you move from North to South. (Source: USGS)
    Range of values
    Minimum:0
    Maximum:79687
    Latitude
    Latitude of transect origin. WGS84 (Source: USGS)
    Range of values
    Minimum:32.530293
    Maximum:48.390034
    Units:decimal degrees
    Longitude
    Longitude of Transect Origin. Negative indicates west longitude. WGS84 (Source: USGS)
    Range of values
    Minimum:-124.732421
    Maximum:-117.126325
    Units:decimal degrees
    X_UTM
    Easting of transect origin (in UTM) (Source: USGS)
    Range of values
    Minimum:224412.773643
    Maximum:775596.336712
    Units:meters
    Y_UTM
    Northing of transect origin (in UTM) (Source: USGS)
    Range of values
    Minimum:3599224.166723
    Maximum:5361076.838198
    Units:meters
    TransSlope
    Slope of the transect line, unitless. Defined using the formula y= m*x+b, where m is the slope, x is the easting of the transect origin, y is the northing of the transect origin and b is the y-intercept. (Source: USGS)
    Range of values
    Minimum:-322.488196
    Maximum:477.800552
    Units:no units
    Y_intercept
    Y-intercept of the transect line, defined using the formula y= m*x+b, where b is the y-intercept, m is the slope, x is the easting of the transect origin, and y is the northing of the transect origin. (Source: USGS)
    Range of values
    Minimum:-261043474.99728
    Maximum:248923456.43136
    Units:meters
    MHW
    The value of Mean High Water (relative to NAVD88) used to calculate the location of the shoreline. (Source: USGS)
    Range of values
    Minimum:1.33
    Maximum:2.1
    Units:meters
    UTMzone
    UTM zone of the transect (Source: USGS)
    Range of values
    Minimum:10
    Maximum:11
    Entity_and_Attribute_Overview:
    This section describes the tabular data associated with the shapefile and the corresponding csv file “referenceLine_WestCoast (.shp/.csv)”. The tabular .csv data does not have the attributes "FID" or "Shape" The shapefile is projected GCS_WGS_1984.
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey - ScienceBase

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Amy S. Farris
    • Kathryn M. Weber
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Amy Farris
    U.S. Geological Survey
    Oceanographer
    384 Woods Hole Road
    Woods Hole Road, MA
    USA

    508-548-8700 x2344 (voice)
    508-547-2310 (FAX)
    afarris@usgs.gov

Why was the data set created?

Beach slope is a critical metric for coastal hazards science and is also necessary for extracting shorelines from satellite imagery. Shorelines derived from satellite data must be tidally-corrected to a reference elevation using the slope of the beach. The beach slope data presented here will be beneficial for advancing our understanding of coastal processes and for quantifying and predicting shoreline change and storm impacts along the Pacific coast.

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: 11-Jan-2001 (process 1 of 2)
    For each state/region a coast-following reference baseline was digitized in UTM using Google Earth. This line was loaded into Matlab (version 2000b) and equally-spaced points were defined along the line at a 20-meter spacing. Transect lines perpendicular the baseline were calculated at each of these points. The transects are defined by their origin point (the point on the baseline) and their slope, and y-intercept using the formula: y = m*x +b Where m is the slope, b is the y intercept, x is the easting of the transect origin and y is the northing of the transect origin. All steps were completed by Amy Farris. Person who carried out this activity:
    Amy S. Farris
    U.S. Geological Survey
    Oceanographer
    384 Woods Hole Road
    Woods Hole, MA
    USA

    508-548-8700 x2344 (voice)
    508-457-2310 (FAX)
    afarris@usgs.gov
    Date: 01-May-2023 (process 2 of 2)
    The reference baseline and transects were merged for all states/regions. The transect origins were converted to a geographic coordinate system. However, since the transect lines are defined in UTM and cannot be expressed in geographic, the transect origins are also provided in UTM. The final data matrix has one row for each transect and each row contains the following information: State, Region, Transect number, Latitude and Longitude of the transect origin, easting and northing of the transect origin, slope, y-intercept, Mean High Water (MHW), UTM zone. This matrix was output as both a .csv and a shapefile. All work was done in Matlab (version 2023a) by Amy Farris.
  3. What similar or related data should the user be aware of?
    Farris, Amy S., Weber, Kathryn M., Doran, Kara S., and List, Jeffrey H., 2018, Comparing methods used by the U.S. Geological Survey Coastal and Marine Geology Program for deriving shoreline position from lidar data: Open-File Report 2018-1121, U.S. Geological Survey, Reston, VA.

    Online Links:

    Weber, Kathryn M., List, Jeffrey H., and Morgan, Karen L.M., 2005, An operational mean high water datum for determination of shoreline position from topographic lidar data: Open-File Report 2005-1027, 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?
    This data file contains the values of Mean High Water (MHW) that were used to estimate the shoreline position. These values were taken from Weber and others (2005) and do not vary continuously along the coast, but rather are constant for long stretches of coastline. The value at any particular point is estimated to be within 15 cm of the 'true' value.
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
    This data file contains the values of Mean High Water (MHW) that were used to estimate the shoreline position. These values were taken from Weber and others (2005) and do not vary continuously along the coast, but rather are constant for long stretches of coastline. The value at any particular point is estimated to be within 15 cm of the 'true' value.
  4. Where are the gaps in the data? What is missing?
    All transects are listed, even transects for which no shoreline was found.
  5. How consistent are the relationships among the observations, including topology?
    Transect numbers are unique for each state, or if the state is divided into regions, for each region.

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 Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset.
  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
    United States

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? The dataset contains the point shapefile and the tabular data which contain information about the reference line and transects, (referenceLine_WestCoast.shp and referenceLine_WestCoast.csv), browse graphic (slope_BrowseGraphic.png), and the FGDC CSDGM metadata in XML format.
  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 for other purposes, nor on all computer systems, 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?
    These data are available in a point shapefile format. The user must have software to read and process the data components of a shapefile.

Who wrote the metadata?

Dates:
Last modified: 10-Apr-2024
Metadata author:
Amy S. Farris
U.S. Geological Survey
384 Woods Hole Road
Woods Hole, MA
USA

508-548-8700 (voice)
508-548-8700 x2306 (FAX)
whsc_data_contact@usgs.gov
Contact_Instructions:
The metadata contact email address is a generic address in the event the person is no longer with USGS.
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/SB_data_release/DR_P137S83C/referenceLine_WestCoast_Metadata.faq.html>
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