Offshore Baseline for Southern California Generated to Calculate Shoreline Change Rates

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Frequently-anticipated questions:

What does this data set describe?

Title:
Offshore Baseline for Southern California Generated to Calculate Shoreline Change Rates
Abstract:
Rates of long-term and short-term shoreline change were generated in a GIS using the Digital Shoreline Analysis System (DSAS) version 3.0; An ArcGIS extension for calculating shoreline change: U.S. Geological Survey Open-File Report 2005-1304, Thieler, E.R., Himmelstoss, E.A., Zichichi, J.L., and Miller, T.M. The extension is designed to efficiently lead a user through the major steps of shoreline change analysis. This extension to ArcGIS contains three main components that define a baseline, generate orthogonal transects at a user-defined separation along the coast, and calculate rates of change (linear regression, endpoint rate, average of rates, average of endpoints, jackknife).
  1. How should this data set be cited?

    Hapke, Cheryl, and Reid, David, 2006, Offshore Baseline for Southern California Generated to Calculate Shoreline Change Rates: Open-File Report 2006-1251, U.S. Geological Survey, Coastal and Marine Geology Program, U.S. Geological Survey, Pacific Science Center, Santa Cruz, Californioa.

    Online Links:

    This is part of the following larger work.

    Hapke, Cheryl, Reid, David, Richmond, Bruce, Ruggiero, Peter, and List, Jeff, Unknown, National Assessment of Shoreline Change: Part 3, Historical Shoreline Changes and Associated Coastal Land Loss Along sandy shorelines of the California coast: Open-File Report 2006-1219, U.S. Geological Survey, Coastal and Marine Geology Program, U.S. Geological Survey, Pacific Science Center, Santa Cruz, California.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -120.005117
    East_Bounding_Coordinate: -117.126636
    North_Bounding_Coordinate: 34.491814
    South_Bounding_Coordinate: 32.499891

  3. What does it look like?

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

    Calendar_Date: 2003
    Currentness_Reference: publication date

  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 Vector data set. It contains the following vector data types (SDTS terminology):

      • String (2)

    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 0.000512
      Ordinates (y-coordinates) are specified to the nearest 0.000512
      Planar coordinates are specified in meters

      The horizontal datum used is North American Datum of 1927.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.400000.
      The flattening of the ellipsoid used is 1/294.978698.

  7. How does the data set describe geographic features?

    SoCal_Baseline
    Baseline for Southern California (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.

    ID
    Feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:1
    Maximum:30

    ACCURACY
    Position accuracy of feature. (Source: U.S. Geological Survey)

    ValueDefinition
    0The accuracy is not given or is not known.

    TYPE
    Type of feature. (Source: U.S. Geological Survey)

    ValueDefinition
    BaselineVector baseline.

    DESCR
    Detailed description of the feature. (Source: U.S. Geological Survey)

    Describes additional characteristics of feature.

    SOURCE
    Agency that provided feature or data used to create feature. (Source: U.S. Geological Survey)

    ValueDefinition
    USGSUnited States Geological Survey

    DATE
    DSAS Generated Field, Not Applicable to Baseline (Source: USGS)

    ValueDefinition
    NoneNo Date

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?

    U.S. Geological Survey, Pacific Science Center
    400 Natural Briges Drive
    Santa Cruz, Ca 95060
    USA

    (831)-427-4450 (voice)
    (831)-427-4748 (FAX)

    Hours_of_Service: Monday through Friday, 8 a.m. to 5 p.m., Eastern Standard Time

Why was the data set created?

Historical shoreline change is considered to be a crucial element in studying the vulnerability of the national shoreline. These data are used in a shoreline change analysis for the USGS National Assessment Project.

How was the data set created?

  1. From what previous works were the data drawn?

    Southern California DSAS Baseline (source 1 of 1)
    Hapke, Cheryl, and Reid, David, Unknown, THE NATIONAL ASSESSMENT OF SHORELINE CHANGE: A GIS Compilation of Vector Shorelines and Associated Shoreline Change Data for the Sandy Shorelines of the California Coast.: OFR 2006-1219, USGS Coastal and Marine Geology Program, USGS Pacific Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Hapke, Cheryl, Reid, David, Richmond, Bruce, Ruggiero, Peter, and List, Jeff, Unknown, National Assessment of Shoreline Change: Part 3, Historical Shoreline Changes and Associated Coastal Land Loss Along sandy shorelines of the California coast: OFR 2006-1219, USGS Coastal and Marine Geology Program, USGS Pacific Science Center, Santa Cruz, California.

    Online Links:

    Type_of_Source_Media: Vector Baseline
    Source_Contribution: USGS

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

    Date: Unknown (process 1 of 1)
    A baseline was manually constructed seaward of, and parallel to, the trend of shorelines representing four general time periods (1800s, 1920s-1930s, 1970s, and 1998-2002). Using DSAS (USGS OFR 2005-1304), transects were generated with a spacing of 50m and transect-shoreline intersection points were saved to a separate layer. Transects were manually eliminated to prevent calculation of rates in areas where less than four shorelines were intersected.
    Long-term rates of shoreline change, in units of m/yr, were calculated at each transect using linear regression applied to all four shoreline positions from the earliest (1800s) to the most recent (derived from lidar). Linear regression was selected because it has been shown to be the most statistically robust quantitative method when a limited number of shorelines are available and it is the most commonly applied statistical technique for expressing shoreline movement and estimating rates of change. Uncertainties for the long-term rates are also reported in units of m/yr and represent a 90% confidence interval for the slope of the regression line. This means with 90% statistical confidence that the true rate of shoreline change falls within the range defined by the reported value plus or minus the error value. The variability around the trend reflects both measurement and sampling errors. Short-term rates of shoreline change, in units of m/yr, were calculated using the endpoint method comparing the 1970s and most recent shoreline positions.

    Person who carried out this activity:

    U.S. Geological Survey, Pacific Science Center
    c/o Bruce Richmond
    400 Natural Bridges Drive
    Santa Cruz, Ca 95060
    USA

    (831)-427-4450 (voice)
    (831)-427-4748 (FAX)

    Hours_of_Service: Monday through Friday, 8 a.m. to 5 p.m., Pacific Standard Time
  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?

  2. How accurate are the geographic locations?

    A Baseline was generated within ArcGIS to be used by the Digital Shoreline Anaylsis System (<http://pubs.usgs.gov/of/2005/1304/>)in the calculation of shoreline change rates. Please visit our full report on shoreline change in the Coastline of California (<http://pubs.usgs.gov/of/2006/1219/>) for more information about this analysis

  3. How accurate are the heights or depths?

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

    This baseine data represents a generalization of the shoreline of California used by DSAS. Remaining gaps in this data, if applicable, are a consequence of non-existing shoreline data.

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

    Baseline generation was made as part of the calculation process for the Digital Shoreline Analysis System an Extension for ArcGIS (<http://pubs.usgs.gov/of/2005/1304/>)

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 (USGS) as the source of this information.

  1. Who distributes the data set? (Distributor 1 of 1)

    U.S. Geological Survey, Pacific Science Center
    600 4th Street South
    St. Petersburg, FL 33701
    USA

    (831)-427-4450 (voice)
    (831)-427-4748 (FAX)

    Hours_of_Service: Monday through Friday, 8 a.m. to 5 p.m., Eastern Standard Time
  2. What's the catalog number I need to order this data set?

    USGS Open-File Report 2006-1219

  3. What legal disclaimers am I supposed to read?

    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: 26-Aug-2006
Metadata author:
U.S. Geological Survey, Center for Coastal and Watershed Studies
c/o Tara Miller
600 4th Street South
St. Petersburg, FL 33701
USA

(727) 803-8747 (voice)
(727) 803-2032 (FAX)
taram@usgs.gov

Hours_of_Service: Monday through Friday, 8 a.m. to 5 p.m., Eastern Standard Time
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.9.1 on Sat Aug 26 11:56:23 2006