NORCAL_TRANSECTS_LT - Long-Term Shoreline Change Rates for Northern California Generated at a 50 m Transect Spacing, 1854-2002

Frequently-asked questions:


What does this data set describe?

Title:
NORCAL_TRANSECTS_LT - Long-Term Shoreline Change Rates for Northern California Generated at a 50 m Transect Spacing, 1854-2002

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?

    Cheryl Hapke, David Reid, 2006, NORCAL_TRANSECTS_LT - Long-Term Shoreline Change Rates for Northern California Generated at a 50 m Transect Spacing, 1854-2002: Open-File Report 2006-1251, U.S. Geological Survey, Coastal and Marine Geology Program, Pacific Science Center, Santa Cruz, CA.

    Online links:
    This is part of the following larger work:

    Cheryl Hapke, David Reid, 2006, National Assessment of Shoreline Change: A GIS Compilation of Vector Shorelines and Associated Shoreline Change Data for the Sandy Shorelines of the California Coast: Open-File Report 2006-1251, U.S. Geological Survey, Coastal and Marine Geology Program, Pacific Science Center, Santa Cruz, CA.

    Online links:
  2. What geographic area does the data set cover?

    Bounding coordinates:
    West: -124.330473
    East: -122.962786
    North: 41.991562
    South: 38.231836

  3. What does it look like?

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

    Calendar date: 2005
    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 (3006)

    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 0.000000. Longitudes are given to the nearest 0.000000. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

  7. How does the data set describe geographic features?

    Norcal_transects_lt
    Southern California Long-Term Transects
    (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.

    OBJECTID
    Feature number.
    (Source:
    DSAS
    )

    Range of values
    Minimum: 1
    Maximum: 5734

    TransOrder
    Transect Sequence
    (Source:
    DSAS
    )

    Range of values
    Minimum: 1
    Maximum: 5734

    BaselineID
    Baseline Identification
    (Source:
    DSAS
    )

    Baseline Identification

    Autogen
    Indicates whether the transect was autogenerated or manually generated.
    (Source:
    DSAS
    )

    Indicates whether the transect was autogenerated or manually generated.

    StartX
    X starting position of the transect in UTM meters.
    (Source:
    DSAS
    )

    X starting position of the transect in UTM meters.

    StartY
    Y starting position of the transect in UTM meters.
    (Source:
    DSAS
    )

    Y starting position of the transect in UTM meters.

    ProcTime
    Date and time the rate calculation was generated.
    (Source:
    DSAS
    )

    Date and time the rate calculation was generated.

    ShorelineD
    Shorelines used in calculation
    (Source:
    DSAS
    )

    Shorelines used in calculation

    EndX
    X Ending position of the transect in UTM meters.
    (Source:
    DSAS
    )

    X Ending position of the transect in UTM meters.

    PointCNT
    Number of shoreline intersections in the rate calculation.
    (Source:
    DSAS
    )

    Number of shoreline intersections in the rate calculation.

    LRR
    Linear regression rate.
    (Source:
    DSAS
    )

    Range of values
    Minimum: -2.36
    Maximum: 3.25
    Units: Meters/Year
    Resolution: 0.1

    LR2
    Correlation coefficient (r^2).
    (Source:
    DSAS
    )

    Range of values
    Minimum: 0
    Maximum: 1
    Units: Meters
    Resolution: 0.1

    EndY
    Y Ending position of the transect in UTM meters.
    (Source:
    DSAS
    )

    Y Ending position of the transect in UTM meters.

    Azimuth
    The transect's horizontal angular distance from north.
    (Source:
    DSAS
    )

    The transect's horizontal angular distance from north.

    LCI90
    Linear Regression Confidence Interval 90%
    (Source:
    DSAS
    )

    Range of values
    Minimum: 0
    Maximum: 7.06
    Units: Meters
    Resolution: 0.1

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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?

    Bruce Richmond
    U.S. Geological Survey
    Pacific Science Center
    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., Eastern Standard Time
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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 U.S. Geological Survey (USGS) National Assessment Project.

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How was the data set created?

  1. Where did the data come from?

    Long-Term Shoreline Change Rate Transects for Northern California (source 1 of 1)

    Cheryl Hapke, David Reid, 2006, 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.: Open File Report 2006-1251, USGS Pacific Science Center, Santa Cruz, CaliforniaU.S. Geological Survey, Coastal and Marine Geology Program.

    Online links:
    This is part of the following larger work:

    Cheryl Hapke, David Reid, Bruce Richmond, Peter Ruggiero, Jeff List, 2006, 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, USGS Pacific Science Center, Santa Cruz, CaliforniaU.S. Geological Survey, Coastal and Marine Geology Program.

    Type of source media: Transects
    Source contribution:
    USGS

  2. What changes have been made?

    (change 1 of 2)
    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, 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 responsible for change:
    Bruce Richmond
    U.S. Geological Survey
    Pacific Science Center
    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

    Date: 20070716 (change 2 of 2)
    Data were projected from UTM zone 10 to geographic with a datum shift from NAD27 to NAD83
    
    Tool: ArcGIS > ArcToolbox > Toolboxes > Data Management Tools > Project
    
    Command issued:
    GEOGCS['GCS_North_American_1983',DATUM['D_North_American_1983',SPHEROID['GRS_1980',6378137.0,298.257222101]],PRIMEM['Greenwich',0.0],UNIT['Degree',0.0174532925199433]] # NAD_1927_To_NAD_1983_NADCON

    Person responsible for change:
    Emily Himmelstoss
    U.S. Geological Survey
    Geologist
    384 Woods Hole Road
    Woods Hole, MA 02543-1598
    USA

    508-548-8700 x2262 (voice)
    (508) 457-2310 (FAX)
    ehimmelstoss@usgs.gov

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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?

    See USGS Open File Report 2006-1219

  3. How accurate are the heights or depths?

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

    This shoreline-transect data adequately represented the intersect at the time of the analysis.  Remaining gaps in this data, if applicable, are a consequence of non-existing data, transects crossing man-made features or existing data that did not meet quality assurance standards.

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

    Transect 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/)

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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.

Distributor 1 of 1

  1. Who distributes the data set?

    U.S. Geological Survey
    Pacific Science Center
    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., Eastern Standard Time

  2. What's the catalog number I need to order this data set?

    Downloadable Data: USGS Open-File Report 2006-1251

  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?

    • Availability in digital form:


    • Data format:
      Seven files comprise the ArcView shapefile: <filename>.dbf, <filename>.shp, <filename>.shx, <filename>.prj, <filename>.avl, <filename>.sbx, <filename>.sbn
      in format SHP
      ESRI polyline shapefile
      Size: 2.652
      Network links:
      http://pubs.usgs.gov/of/2006/1251/NCal.zip
      http://pubs.usgs.gov/of/2006/1251/#gis

    • Cost to order the data: None


  5. Is there some other way to get the data?

  6. What hardware or software do I need in order to use the data set?

    These data are available in Environmental Systems Research Institute (ESRI) shapefile format. The user must have ArcGIS or ArcView 3.0 or greater software to read and process the data file. In lieu of ArcView or ArcGIS, the user may utilize another GIS application package capable of importing the data. A free data viewer, ArcExplorer, capable of displaying the data is available from ESRI at www.esri.com.

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Who wrote the metadata?

Dates:
Last modified: 20070716
Last reviewed: 20070301

Metadata author:
U.S. Geological Survey
Pacific Science Center
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., Eastern Standard Time

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

Metadata extensions used:
  • http://www.esri.com/metadata/esriprof80.html

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