Alaska: Icy Cape to Cape Prince of Wales offshore baselines generated to calculate shoreline change rates

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Frequently anticipated questions:

What does this data set describe?

Title:
Alaska: Icy Cape to Cape Prince of Wales offshore baselines generated to calculate shoreline change rates
Abstract:
This dataset includes a reference baseline used by the Digital Shoreline Analysis System (DSAS) to calculate rate-of-change statistics for the exposed coast of Alaska from Icy Cape and Cape Prince Wales for the time period 1948 to 2016. This baseline layer serves as the starting point for all transects cast by the DSAS application and can be used to establish measurement points used to calculate shoreline-change rates.
Supplemental_Information:
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Although this Federal Geographic Data Committee-compliant metadata file is intended to document the dataset in nonproprietary form, as well as in Esri format, this metadata file may include some Esri-specific terminology.
  1. How might this data set be cited?
    Snyder, Alexander G., and Gibbs, Ann E., 20191227, Alaska: Icy Cape to Cape Prince of Wales offshore baselines generated to calculate shoreline change rates: data release DOI: 10.5066/P9H1S1PV, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

    This is part of the following larger work.

    Snyder, Alexander G., and Gibbs, Ann E., 2019, National Assessment of Shoreline Change: A GIS compilation of vector shorelines and associated shoreline change data for the north coast of Alaska, Icy Cape to Cape Prince of Wales: data release DOI: 10.5066/P9H1S1PV, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -168.127648502765
    East_Bounding_Coordinate: -161.054806597465
    North_Bounding_Coordinate: 70.3309867174378
    South_Bounding_Coordinate: 65.5822749027625
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2019
    Currentness_Reference:
    publication date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: polyline shapefile
  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 (52)
    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 0.0196106556. Longitudes are given to the nearest 0.0558147069. Latitude and longitude values are specified in Decimal seconds. The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257223563.
  7. How does the data set describe geographic features?
    Attribute Table
    Table containing attribute information associated with the dataset. (Source: Producer defined)
    FID
    Index number unique to each record in the attribute table. (Source: Assigned by ArcMap)
    Range of values
    Minimum:0
    Maximum:51
    Shape
    Defines what type of spatial information is associated with this record (for example, polyline, polygon, point). (Source: Assigned by ArcMap.)
    ValueDefinition
    PolylineA shape defined by one or more paths, in which a path is a series of connected segments.
    ID
    Field required by the Digital Shoreline Analysis System (DSAS) software. DSAS uses this value to determine the ordering sequence of transects when the baseline feature contains multiple segments. Individual segments are numbered sequentially alongshore. (Source: U.S. Geological Survey)
    Range of values
    Minimum:101
    Maximum:231
    SHAPE_Leng
    Length of the polyline represented by this record. (Source: Producer defined.)
    Range of values
    Minimum:1333.921452
    Maximum:142819.277739
    Units:Meters

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Alexander G. Snyder
    • Ann E. Gibbs
  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

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

Why was the data set created?

Beach erosion is a persistent problem along most open-ocean shores of the United States. Along the Arctic coast of Alaska, coastal erosion is widespread and is threatens Native communities, defense and energy-related infrastructure, and coastal habitat. As coastal populations continue to expand and infrastructure and habitat are increasingly threatened by erosion, there is increased demand for accurate information regarding past and present trends and rates of shoreline movement. There also is a need for a comprehensive analysis of shoreline change with metrics that are consistent from one coastal region to another. To meet these national needs, the U.S. Geological Survey is conducting an analysis of historical shoreline changes along the open-ocean sandy shores of the conterminous United States and parts of Hawaii, Alaska, and the Great Lakes. One purpose of this work is to develop standard, repeatable methods for mapping and analyzing shoreline change so that periodic, systematic, and internally consistent updates regarding coastal erosion and land loss can be made nationally.

How was the data set created?

  1. From what previous works were the data drawn?
    T-sheets (source 1 of 1)
    National Oceanic and Atmospheric Administration, Unpublished material, Topographic sheets (T-sheets): National Oceanic and Atmospheric Administration, online.

    Online Links:

    Type_of_Source_Media: Digital Data (.tif)
    Source_Contribution:
    T-sheet imagery was used to delineate approximate land-water interface. The baseline in this dataset was initially generated by creating an offset of the T-sheet derived shoreline.
  2. How were the data generated, processed, and modified?
    Date: 2019 (process 1 of 6)
    Baselines were constructed offshore from the time series of shoreline positions using standard editing tools in Esri ArcMap v. 10.6. The baselines were positioned to conform to changes in the orientation of the historical shorelines also presented in this data release. This was done so that transects, which are generated by the Digital Shoreline Analysis System v 4.4 from the baseline, would intersect perpendicular to the general trend of the shorelines.
    Date: 2019 (process 2 of 6)
    The joined baseline feature class was exported to a shapefile in ArcMap v10.6 by right-clicking the transect layer.
    Date: 2019 (process 3 of 6)
    The exported baseline shapefile was projected in Esri's ArcToolbox (v10.6); Data Management Tools; Projections and Transformations; Feature; Project. Parameters: input projection - UTM zone 3 (NAD83); output projection - geographic coordinates (WGS84); transformation = WGS_1984_(ITRF00)_To_NAD_1983.
    Date: 19-Oct-2020 (process 4 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: 13-Oct-2021 (process 5 of 6)
    Performed minor edits to the metadata to correct typos. No data were changed Person who carried out this activity:
    U.S. Geological Survey
    Attn: Susan A. Cochran
    Geologist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7545 (voice)
    scochran@usgs.gov
    Date: 20-Mar-2026 (process 6 of 6)
    The metadata title was modified to move the location name to the beginning of the title. This was done to meet system requirements as ScienceBase is migrated to a new platform, and to keep datasets grouped alphabetically by location on the new data release landing page.(20260320). Person who carried out this activity:
    Manda Au
    U.S. Geological Survey
    Data Management Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7575 (voice)
    mau@usgs.gov
  3. What similar or related data should the user be aware of?
    Gibbs, Ann E., Snyder, Alexander G., and Richmond, Bruce M., 2019, National Assessment of Shoreline Change: Historical Shoreline Change Along the North Coast of Alaska, Icy Cape to Cape Prince of Wales..

    Online Links:

    • https:/doi.org/10.3133/ofr20191146

    Other_Citation_Details:
    Gibbs, A.E., Snyder, A.G., Richmond, B.M., 2019, National Assessment of Shoreline Change: Historical Shoreline Change Along the North Coast of Alaska, Icy Cape to Cape Prince of Wales: U.S. Geological Survey Open-File Report 2019-1146.
    Thieler, Robert E., Himmelstoss, Emily A., Zichichi, Jessica L., and Ergul, Ayhan, 2009, Digital Shoreline Analysis System (DSAS) version 4.0 - An ArcGIS extension for calculating shoreline change.

    Online Links:

    Other_Citation_Details:
    Thieler, E.R., Himmelstoss, E.A., Zichichi, J.L., and Ergul, A., 2009, Digital Shoreline Analysis System (DSAS) version 4.0—An ArcGIS extension for calculating shoreline change: U.S. Geological Survey Open-File Report 2008-1278.

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    The attribute in this layer is based on the requirements for use within the Digital Shoreline Analysis System (DSAS) software (USGS Open-File Report 2008-1278). The data have been quality checked.
  2. How accurate are the geographic locations?
    The baseline serves as a reference point for transects cast by the Digital Shoreline Analysis System (DSAS) software. It does not correspond to any real-world feature.
  3. How accurate are the heights or depths?
    The baseline serves as a reference point for transects cast by the Digital Shoreline Analysis System (DSAS) software. It does not correspond to any real-world feature.
  4. Where are the gaps in the data? What is missing?
    This baseline file is complete and contains all baseline segments used to cast transects where shoreline data are present to calculate a rate of change.
  5. How consistent are the relationships among the observations, including topology?
    All polylines have a unique identification attribute (ID). This field is used by the Digital Shoreline Analysis System (DSAS) to designate the alongshore order of baselines if there are more than one. Adjacent baseline segments do not overlap and are not necessarily continuous.

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 USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey as the originator(s) of the dataset and in products derived from these data.
  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

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? These data are available in shapefile format contained in a single zip file, which also includes CSDGM FGDC-compliant metadata.
  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 on any other system or for general or scientific purposes, 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?
    This zip file contains data available in Environmental Systems Research Institute (Esri) polyline 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: 20-Mar-2026
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: PCMSC Science Data Coordinator
2885 Mission Street
Santa Cruz, CA

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/DataReleases/ScienceBase/DR_P9H1S1PV/WestChukchi_Baselines_metadata.faq.html>
Generated by mp version 2.9.51 on Fri Apr 10 16:37:33 2026