socal1932_1934.shp - Vectorized Cliff Edge of Southern California Derived from 1932-1934 Source Data

Frequently-asked questions:


What does this data set describe?

Title:
socal1932_1934.shp - Vectorized Cliff Edge of Southern California Derived from 1932-1934 Source Data

Abstract:
There are critical needs for a nationwide compilation of reliable cliff edge data.  To meet these needs, the USGS has produced a comprehensive database of digital vector cliff edges by compiling cliff edge positions from pre-existing historical cliff edge databases and by generating historical and modern cliff edge data.  Cliff edges are compiled by state and generally correspond to two periods: 1920s-1930s and 1998-2002.  Each cliff edge may represent a compilation of data from one or more sources for one or more dates provided by one or more agencies.  Details regarding source are provided in the 'data quality information' section of this metadata report.  Cliff edge vectors derived from both historic sources (first time period) and modern sources (final time period) represent the cliff edge at the time of the survey.

  1. How should this data set be cited?

    Cheryl Hapke, David Reid, 2007, socal1932_1934.shp - Vectorized Cliff Edge of Southern California Derived from 1932-1934 Source Data: Open-File Report 2007-1112, U.S. Geological Survey, Coastal and Marine Geology Program, U.S. Geological Survey, Pacific Science Center, Santa Cruz, California.

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

    Cheryl Hapke, David Reid, Krystal Green, Mark Borrelli, 2007, National Assessment of Shoreline Change: Part 4: A GIS Compilation of Vector cliff edges and associated change data for the cliffed shorelines of the California Coast: Open-File Report 2007-1112, U.S. Geological Survey, Coastal and Marine Geology Program, U.S. Geological Survey, Pacific Science Center, Santa Cruz.

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

    Bounding coordinates:
    West: -119.999829
    East: -117.235386
    North: 34.494209
    South: 32.630949

  3. What does it look like?

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

    Beginning date: 1932
    Ending date: 1934
    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 Vector data set. It contains the following vector data types (SDTS terminology):
      • String (58)

    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 0.000001. Longitudes are given to the nearest 0.000001. 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?

    SoCal1932_1934
    Vector Cliff Edge from NOS T-Sheets
    (Source:
    U.S. Geological Survey
    )

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

    Range of values
    Minimum: 1
    Maximum: 40677

    Shape
    Feature geometry.
    (Source:
    ESRI
    )

    Coordinates defining the feature.

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

    Describes additional characteristics of the feature.

    FID
    Internal feature number
    (Source:
    ESRI
    )

    Sequential unique whole numbers that are automatically generated.

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

    Value Definition
    0
    The accuracy is not given but should be 1.4 meters.

    Date_
    Date of vector cliff edge position
    (Source:
    U.S. Geological Survey
    )

    Range of values
    Minimum: 1932
    Maximum: 1934

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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?

    Cheryl Hapke
    U.S. Geological Survey
    Geologist
    Patuxent Wildlife Research Center
    University of Rhode Island
    317 Woodward Hall, Dept. of Geosciences
    Kingston, RI 02881
    USA

    401-874-5532 (voice)
    401-874-2190 (FAX)
    chapke@usgs.gov
    Hours of Service: Monday through Friday, 9 a.m. to 5 p.m., Eastern Standard Time
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Why was the data set created?

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

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How was the data set created?

  1. Where did the data come from?

    NOS T-Sheets (source 1 of 1)

    U.S. Department of Commerce, National Oceanic and Atmospheric Administration (NOAA), National Environmental Satellite, Data, and Information Service (NESDIS), and National Ocean Service (NOS), 2006, Vector Shorelines from Georeferenced Scanned Coastal Maps: Historic Shoreline Database 1930s Shoreline, U.S. Department of Commerce, National Oceanic and Atmospheric Administration, Silver Spring, Maryland.

    Online links:
    Other citation details:
    Senior cartographer, 1315 East-West Highway, Silver Spring, MD 20910-3282, Voice (301) 713-3226, FAX (301) 713-4176, Email <info_center@ngs.noaa.gov>.

    Type of source media: paper
    Source contribution:
    NOAA NOS Topographic Sheets (t-sheet or tp-sheet maps)

  2. What changes have been made?

    Date: 2006 (change 1 of 2)
    Cliff edges from one or more sources were sought in an effort to develop a single cliff edge for each time period.  Digital cliff edges, if available from another agency, were acquired.  If no digital cliff edges were available or if a data set was incomplete, T-sheets were requested from NOAA and received as scanned raster images.  T-sheets were geo-registered using ERDAS Imagine geographic imaging software by placing 6-10 well-spaced ground control points at gridline intersections.  Some T-sheets may have required additional coordinate transformation information from NOAA to account for datum offsets between historical datums (USSD) and modern datums (NAD27 or NAD83).  Datum transformations were applied to GCP coordinates prior to registration.  Total RMS error for the rectification process was maintained below 1 pixel, which translates to approximately 4m at a scale of 1:20,000 and 1.5m at a scale of 1:10,000.  Geo-registered T-sheets were loaded in ArcView and vector cliff edges were digitized.
    
    Quality assessments were performed and cliff edges were edited to remove any overlap between adjacent cliff edges.  No edgematching between adjacent cliff edges was attempted. Finally, cliff edges from all sources were merged to produce a single cliff edge for the period.  The final cliff edge was coded with 6 attribute fields (ID, Type, Date, Descr, Source, and Accuracy) required for the Digital Shoreline Analysis System (DSAS), which was used to calculate cliff edge erosion rates.  The attributes reflect the source of the data and the original survey year.

    Person responsible for change:
    Cheryl Hapke
    U.S. Geological Survey
    Geologist
    USGS Patuxent Wildlife Research Center
    University of Rhode Island
    Coastal Field Station
    317 Woodward Hall, Dept. of Geosciences
    Kingston, RI 02881
    USA

    401-874-5532 (voice)
    401-874-2190 (FAX)
    chapke@usgs.gov
    Hours of Service: Monday through Friday, 8am to 5pm EST

    Date: 20070215 (change 2 of 2)
    Data were projected from UTM zone 11 to geographic
    
    Tool: ArcGIS > ArcToolbox > Toolboxes > Data Management Tools > Project
    
    Command issued:
    ['GCS_North_American_1983',DATUM['D_North_American_1983',SHPERIOD['GRS_1980',6378137.0,298.25722101]],PRIMEM['Greenwich',0.0],UNIT['Degree',0.0174532925199433]]

    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?

    The data supplied here are a compilation of information collected from numerous National Ocean Service Coastal Survey Maps (often referred to as t-sheets or tp-sheets). In compiling this product we made no attempt to ascertain the congruency between the charted data, and the real world. Our objective was to simply capture the representative coastline as provided to us via the NOS survey maps. Every effort was made to capture the shoreline on these charts as faithfully as our skills and technology allowed, and there is every indication that we were successful to this end. However, in doing so, we automatically conveyed the character (all aspects, both good and bad) of those data to our digital product. A character which may or may not be in agreement with the real world. Because of this, the user is advised to exercise caution in making any assumptions about the fallibility, or infallibility, of the spatial information supplied here; especially when circumstances warrant a high degree of absolute positional accuracy.

  2. How accurate are the geographic locations?

    The maximum estimated positional error for this shoreline is 13.9 meters. Please visit our full report on shoreline change in the Coastline of California (http://pubs.usgs.gov/of/2007/1133/), under the heading 'Uncertainties and Errors', for a complete explanation of the measurement error.

  3. How accurate are the heights or depths?

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

    This shoreline data adequately represented the shoreline at the time of the survey.  Remaining gaps in these data, if applicable, are a consequence of non-existing data or existing data that did not meet quality assurance standards.

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

    There is significant agreement of linework between adjacent shorelines.  Shorelines were checked for accuracy, but no edgematching attempts were made between adjacent shorelines even if slight offsets existed.

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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 are freely redistributable with proper metadata and source attribution.  The U.S. Geological Survey (USGS) must be referenced as the originator of the dataset in any future products or research derived from these data.

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

  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:
      in format SHP (version Unspecified)
      ESRI Polyline Shapefile. The DBF file contains the attribute data in dBASE format. The PRJ file contains the coordinate system information. The SBN and SBX files contain the spatial index of the geospatial data. The SHP file contains the geospatial data. The SHX file contains the index of the geospatial data. The XML file contains the metadata describing the data set.
      Size: 0.348
      Network links:
      http://pubs.usgs.gov/of/2007/1112/SCal.zip
      http://pubs.usgs.gov/of/2007/1112/

    • 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: 20070319

Metadata author:
Cheryl Hapke
U.S. Geological Survey
USGS Patuxent Wildlife Research Center
University of Rhode Island
Coastal Field Station
317 Woodward Hall, Dept. of Geosciences
Kingston, RI 02881
USA

401-874-5532 (voice)
401-874-2190 (FAX)
chapke@usgs.gov

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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