SOCAL_1998 - Vectorized Shoreline of Southern California Derived from 1998 Lidar Source Data

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Frequently anticipated questions:

What does this data set describe?

Title:
SOCAL_1998 - Vectorized Shoreline of Southern California Derived from 1998 Lidar Source Data
Abstract:
There are critical needs for a nationwide compilation of reliable shoreline data. To meet these needs, the U.S. Geological Survey (USGS) has produced a comprehensive database of digital vector shorelines by compiling shoreline positions from pre-existing historical shoreline databases and by generating historical and modern shoreline data. Shorelines are compiled by state and generally correspond to one of four time periods: 1800s, 1920s-1930s, 1970s, and 1998-2002. Each shoreline 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. Shoreline vectors derived from historic sources (first three time periods) represent the high water line at the time of the survey, whereas modern shorelines (final time period) represent the mean high water line.
  1. How might this data set be cited?
    Hapke, Cheryl, and Reid, David, 2006, SOCAL_1998 - Vectorized Shoreline of Southern California Derived from 1998 Lidar Source Data: Open-File Report 2006-1251, U.S. Geological Survey, Pacific Science Center, Santa Cruz, CA.

    Online Links:

    This is part of the following larger work.

    Hapke, Cheryl, and Reid, David, 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, Pacific Science Center, Santa Cruz, CA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -119.998365
    East_Bounding_Coordinate: -117.131602
    North_Bounding_Coordinate: 34.456515
    South_Bounding_Coordinate: 32.576153
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 1998
    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 (15527)
    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?
    Socal_1998
    Vector Shoreline from Lidar Overflight (Source: USGS)
    FID
    Internal feature number. (Source: ESRI) Sequential unique whole numbers that are automatically generated.
    ACCURACY
    Position accuracy of feature. (Source: U.S. Geological Survey)
    ValueDefinition
    0The accuracy is not given or is not known.
    Shape
    Feature geometry. (Source: ESRI) Coordinates defining the features.
    ID
    Feature number. (Source: U.S. Geological Survey)
    Range of values
    Minimum:1
    Maximum:40677
    TYPE
    Type of feature. (Source: U.S. Geological Survey)
    ValueDefinition
    ShorelineVector shoreline.
    DESCR
    Detailed description of the feature. (Source: U.S. Geological Survey) Describes additional characteristics of the feature.
    SOURCE
    Agency that provided feature or data used to create feature. (Source: U.S. Geological Survey) Describes source data of the feature.
    DATE_
    Date of Lidar Over Flight (Source: USGS)
    Range of values
    Minimum:19980410
    Maximum:19980410

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Cheryl Hapke
    • David Reid
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    Attn: PCMSC Science Data Coordinator
    2885 Mission Street
    Santa Cruz, CA
    US

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

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.

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: 2002 (process 1 of 6)
    The USGS in collaboration with NASA, used the NASA Airborne Topographic Mapper (ATM II and III) mounted on a Twin Otter Aircraft to map coastal beaches. The raw data was georeferenced at elevation points every few square meters. The original data from ATM was collected in WGS 84, ITRF 97, in a geographic (lat/long) coordinate system with irregular spacing. The data was then converted to NAD 83 and NAVD 88. The shoreline generation involved an analysis of shore-normal profiles at 20m intervals alongshore. First, a shore-parallel reference line was digitized as a permanent baseline for any future shoreline generation. Profiles were assessed at 20m intervals perpendicular to the reference line. Each profile consisted of a 4m wide swath of data points. An algorithm determined the shoreline position for each profile based on a regression fit through the foreshore of the profile. The function was evaluated at the mean high water (mhw) level to identify the horizontal position of the shoreline. Results were only accepted if the R-squared value of the regression was significant to the 95% confidence level. The shoreline point solutions were then quality checked in ArcView GIS software against a gray scale elevation grid of the same data. Point solutions were connected to produce a continuous vector shoreline in shapefile forma t. Process date is estimated. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Bruce Richmond
    Pacific Science Center
    Santa Cruz, Ca
    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: 15-Feb-2007 (process 2 of 6)
    Data were projected from UTM zone 10 to geographic with Datum shift from NAD27 to NAD83_6
    Tool: ArcGIS > ArcToolbox > Toolboxes > Data Management Tools > Project
    Command issued:
    ['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_6 Person who carried out this activity:
    Emily Himmelstoss
    U.S. Geological Survey
    Geologist
    384 Woods Hole Road
    Woods Hole, MA
    USA

    508-548-8700 x2262 (voice)
    (508) 457-2310 (FAX)
    ehimmelstoss@usgs.gov
    Date: 07-Feb-2017 (process 3 of 6)
    Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alan O. Allwardt
    Contractor -- Information Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7551 (voice)
    831-427-4748 (FAX)
    aallwardt@usgs.gov
    Date: 26-Apr-2018 (process 4 of 6)
    Added keywords from Coastal and Marine Ecological Classification Standard (CMECS) to metadata. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alan O. Allwardt
    Contractor -- Information Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7551 (voice)
    831-427-4748 (FAX)
    aallwardt@usgs.gov
    Date: 19-Oct-2020 (process 5 of 6)
    Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 25-Oct-2021 (process 6 of 6)
    Edited metadata to perform minor edits to bring the metadata up to current PCMSC standards. No data were changed. The metadata available from a harvester may supersede metadata bundled within a download file. Users are advised to compare the metadata dates to determine which metadata file is most recent. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Susan Cochran
    Geologist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7545 (voice)
    scochran@usgs.gov
  3. What similar or related data should the user be aware of?
    Hapke, Cheryl J., Reid, David, Richmond, Bruce M., Ruggiero, Peter, and List, Jeff, 2006, National Assessment of Shoreline Change Part 3: Historical Shoreline Change and Associated Coastal Land Loss Along Sandy Shorelines of the California Coast: Open-File Report 2006-1219, U.S. Geological Survey, Pacific Science Center, Santa Cruz, CA.

    Online Links:

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?
    The maximum positional error for this shoreline, considered independently, is 1.5m. However, if the lidar mean high water shoreline (mhwl) is used for comparison with other high water shorelines (hwl), an additional shoreline proxy offset must be considered. When the offset error is considered, as it pertains to lidar shorelines of the coastline of California, it varies based on beach slope, wave height, wave length, and tide level. Calculations of these parameters along the open coastline of California were made in order to quantify this bias offset. Please visit our full report on shoreline change along the sandy shoreline of the coast of California (http://pubs.usgs.gov/of/2006/1219/), 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 this 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.

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:
This data set is not to be used for navigational purposes.
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
    Santa Cruz, Ca
    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 shapefile (version 20060901) ESRI polyline shapefile Size: 1.361
      Network links: http://pubs.usgs.gov/of/2006/1251/SCal.zip
      http://pubs.usgs.gov/of/2006/1251/#gis
    • Cost to order the data: None

  5. 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.

Who wrote the metadata?

Dates:
Last modified: 25-Oct-2021
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: PCMSC Science Data Coordinator
2885 Mission Street
Santa Cruz, CA
US

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/SeriesReports/OFR/OFR_2016-1251/socal_1998.shp.faq.html>
Generated by mp version 2.9.50 on Tue Oct 26 16:49:33 2021