Alaska: Icy Cape to Cape Prince of Wales shorelines (1948 to 2016) used 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 shorelines (1948 to 2016) used to calculate shoreline change rates
Abstract:
This dataset includes shorelines that span 68 years, from 1948 to 2016, for the north coast of Alaska from Icy Cape to Cape Prince of Wales. Shorelines were compiled from topographic survey sheets (T-sheets; National Oceanic and Atmospheric Administration (NOAA)) and aerial orthophotographs (U.S. Geological Survey (USGS) and Alaska High Altitude Photography (AHAP)). Historical shoreline positions serve as easily understood features that can be used to describe the movement of beaches through time. These data are used to calculate rates of shoreline change for the U.S. Geological Survey's National Assessment of Shoreline Change Project. Rates of long-term and short-term shoreline change were generated in a GIS using the Digital Shoreline Analysis System (DSAS) version 4.4. DSAS uses a measurement baseline method to calculate rate-of-change statistics. Transects are cast from the reference baseline to intersect each shoreline, establishing 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 shorelines (1948 to 2016) used 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: -168.125477210333
    East_Bounding_Coordinate: -161.551585613264
    North_Bounding_Coordinate: 70.3304809057524
    South_Bounding_Coordinate: 65.6000415003095
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 01-Jul-1948
    Ending_Date: 03-Sep-2016
    Currentness_Reference:
    Ground condition
  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 (3168)
    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:2327
    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.
    DATE_
    Date on which the source imagery for the digitized shorelines was collected. The precision of the date provided is specified in the ‘Default_D’ field. When only the year was defined, July 1 was used for the month and day. When only the month and year were defined, the first of the month was used. (Source: Producer defined.)
    Range of values
    Minimum:07/01/1948
    Maximum:09/03/2016
    Units:Days, Months, Years
    Year_
    Year in which the source imagery for the digitized shorelines was collected. (Source: Producer defined.)
    Range of values
    Minimum:1948
    Maximum:2016
    Units:Years
    Resolution:1
    Uncy
    total shoreline position uncertainty, in meters. Actual shoreline position is within the range of this value. The uncertainty was determined by equation 1 in Gibbs and others (2019). (Source: Producer defined.)
    Range of values
    Minimum:1
    Maximum:22.4
    Units:Meters
    Resolution:0.1
    Default_D
    Number that indicates the precision of the source imagery collection date. (Source: Producer defined.)
    ValueDefinition
    0The year, month, and day of source imagery collection are known.
    1The year of source imagery collection is known.
    2The year and month of source imagery collection are known.
    Source
    Identifies the source of the map or imagery from which the shorelines in this dataset were digitized. (Source: Producer defined.)
    ValueDefinition
    NOAA, T-SheetNational Oceanographic and Atmospheric Administration Topographic Sheets.
    NASA, Alaska High Altitude PhotographyOrthorectified Alaska high altitude photography mosaics
    Fairbanks FODAR SfM – State of Alaska OrthoimageryOrthorectified aerial photo mosaics generated by Fairbanks FODAR using Structure from Motion (SfM).
    Lestak and others, 2010Published shorelines generated by Lestak and others (2010) using orthorectified photo mosaics.
    Source_a
    Identification numbers used by the organization that produced the imagery or map from which the shorelines were digitized. The identification number convention varies base on the source of the map or imagery, which is identified in the attribute 'Source'. NOAA, T-sheets: refers to the unique identification number on the original topographic maps. NASA--Alaska High Altitude Photography: refers to the unique identification number given to individual image files produced by the organization that post-processed the imagery. Lestak and others 2010: refers to the unique identification number given to individual image files produced by the organization that post-processed the imagery. Fairbanks FODAR SfM--USGS Orthoimagery: refers to the unique identification number given to individual image files produced by the organization that post-processed the imagery. (Source: Producer defined.) Unique identifier assigned by the organization that produced the source data
    Shape_Leng
    Length of the shoreline segment. (Source: Producer defined)
    Range of values
    Minimum:10.298835
    Maximum:21098.001620
    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 5)
    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 the MHW shoreline.
    AHAP (source 2 of 5)
    U.S. Fish and Wildlife Service, Arctic Landscape Conservation Cooperative, and University of Alaska, Fairbanks’ Alaska Satellite Facility and the Geographic Information Network of Alaska, 2012, Orthorectified 1:64,000-scale color-infrared Alaska High-Altitude Aerial Photography: Unpublished data, Unpublished data.

    Type_of_Source_Media: Digital Data (.tif)
    Source_Contribution:
    Alaska high altitude aerial photography was used to delineate the instantaneous land-water interface shoreline.
    AHAP (source 3 of 5)
    U.S. Geological Survey, and Far North Geospatial, LLC, Unpublished material, Orthorectified 1:64,000-scale color-infrared Alaska High-Altitude Aerial Photography: Unpublished data, Unpublished data.

    Type_of_Source_Media: Digital Data (.tif)
    Source_Contribution:
    Alaska high altitude aerial photography was used to delineate the instantaneous land-water interface shoreline.
    Fodar (source 4 of 5)
    Overbeck, J. R., Hendricks, M. D., and N. E. M. Kinsman, 2017, Photogrammetric digital surface models and orthoimagery for the continuous coastline, Wales to Platinum, Alaska, segment A: Wales to Teller.: Alaska Division of Geological & Geophysical Surveys, online.

    Online Links:

    Type_of_Source_Media: Digital Data (.tif)
    Source_Contribution:
    Fodar imagery was used to delineate the instantaneous land-water interface shoreline.
    Fodar (source 5 of 5)
    U.S. Geological Survey, and Fodar, Fairbanks, Unpublished material, Orthorectified natural color aerial photography for the continuous coastline, Icy Cape to Cape Prince of Wales: Unpublished data, Unpublished data.

    Type_of_Source_Media: Digital Data (.tif)
    Source_Contribution:
    Fodar imagery was used to delineate the instantaneous land-water interface shoreline.
  2. How were the data generated, processed, and modified?
    Date: 2019 (process 1 of 6)
    High-resolution scans of T-sheets were geo-registered using Esri ArcMap software (v10.6) by placing 4 well-spaced registration points at gridline intersections of registered T-Sheets of lower resolution and applying a first-order polynomial transformation. An additional 1-10 ground control points (GCPs) were placed using benchmarks and geomorphic features with known locations, then applying a first-order polynomial transformation.
    Date: 2019 (process 2 of 6)
    Vector shorelines were digitized from all data sources using standard editing tools in ArcMap 10.6 using criteria described in Gibbs and others (2019).
    Date: 2019 (process 3 of 6)
    Attributes describing geomorphic setting and specifics of source data were added to vector shorelines.
    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.
    Lestak, L. R., Manley, W. F., and Parrish, E. G., 2010, Digital Shoreline Analysis of Coastal Change in Bering Land Bridge NP (BELA) and Cape Krusenstern NM (CAKR).

    Other_Citation_Details:
    Lestak, L.R., Manley, W.F., and Parrish, E.G., 2010, Digital Shoreline Analysis of Coastal Change in Bering Land Bridge NP (BELA) and Cape Krusenstern NM (CAKR), Northwest Alaska: Fairbanks, AK: National Park Service, Arctic Network I&M Program. Digital Media.

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

  1. How well have the observations been checked?
    The attributes in this table record positional and measurement uncertainties and datum offsets calculated during the process of extracting a land/water interface shoreline from the orthoimagery data as described in the process steps. The field names are based on the requirements for use within the Digital Shoreline Analysis System (DSAS) software (USGS Open-File Report 2008-1278).
  2. How accurate are the geographic locations?
    Shoreline data have been acquired from 1948 to 2016, the horizontal accuracy of which varies with respect to the data source from which the shorelines were digitized and the time period. Shorelines digitized from the 1980s era Alaska High Altitude Photography (AHAP) have an estimated shoreline position uncertainty of plus or minus 10.4 to 22.4 meters. Shorelines digitized from the 1940s and 1950s era T-sheets have an estimated total shoreline position uncertainty of plus or minus 15.7 meters. Shorelines digitized from 2016 orthophotographs have an estimated total shoreline position uncertainty of plus or minus 2.1 to 3.8 meters. Shorelines used in this analysis that were published in Lestak and others (2010) have an estimated total shoreline position uncertainty ranging from 2.3 to 2.9 meters, 2.2 to 2.7 meters, and 1.7 to 1.0 meters for orthoimagery collected in the 1950s, 1980s, and 2003, respectively. Please visit the 'Estimation of Shoreline Position Uncertainty' section in Gibbs and others (2019) for a complete explanation of the measurement uncertainties associated with these shorelines.
  3. How accurate are the heights or depths?
    A formal accuracy assessment of the vertical positional information in the dataset has either not been conducted, or is not applicable.
  4. Where are the gaps in the data? What is missing?
    This shoreline file is complete and contains all shoreline segments used to calculate shoreline change rates along sections of the specified Alaska coastal region where shoreline position data were available. These data adequately represented the shoreline position at the time of the survey. Remaining gaps in these data are a consequence of nonexisting data or existing data that did not meet quality assurance standards.
  5. How consistent are the relationships among the observations, including topology?
    Adjacent shoreline segments do not overlap and are not necessarily continuous. Shorelines were quality checked for accuracy. Any slight offsets between adjacent segments due to georeferencing and digitizing error are taken into account in the uncertainty calculations included in Gibbs and others (2019).

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_shorelines_metadata.faq.html>
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