Digital Shoreline Analysis System (DSAS) version 5.1 transects with long-term linear regression rate calculations for the sheltered eastern Beaufort Sea coast of Alaska from the U.S. Canadian Border to the Hulahula River

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Frequently anticipated questions:

What does this data set describe?

Title:
Digital Shoreline Analysis System (DSAS) version 5.1 transects with long-term linear regression rate calculations for the sheltered eastern Beaufort Sea coast of Alaska from the U.S. Canadian Border to the Hulahula River
Abstract:
This dataset consists of long-term (70 years) shoreline change rates for the mainland coast of Alaska sheltered by barrier islands from the U.S. Canadian Border to the Hulahula River. Rate calculations were computed within a GIS using the Digital Shoreline Analysis System (DSAS) version 5.1, an ArcGIS extension developed by the U.S. Geological Survey. Long-term rates of shoreline change were calculated using a linear regression rate-of-change method based on available shoreline data between 1947 and 2017. A reference baseline was used as the originating point for the orthogonal transects cast by the DSAS software. The transects intersect each shoreline establishing measurement points, which are then used to calculate long-term 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 data set 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?
    Gibbs, Ann E., Ohman, Karin A., Coppersmith, Ryan, and Richmond, Bruce M., 20240911, Digital Shoreline Analysis System (DSAS) version 5.1 transects with long-term linear regression rate calculations for the sheltered eastern Beaufort Sea coast of Alaska from the U.S. Canadian Border to the Hulahula River: data release 10.5066/F72Z13N1, U.S. Geological Survey, Coastal and Marine Geology Program, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz.

    Online Links:

    This is part of the following larger work.

    Gibbs, Ann E., Ohman, Karin A., Coppersmith, Ryan, and Richmond, Bruce M., 2017, National Assessment of Shoreline Change: A GIS compilation of Updated Vector Shorelines and Associated Shoreline Change Data for the North Coast of Alaska, U.S. Canadian Border to Icy Cape (ver. 2.0, September 2024): data release 10.5066/F72Z13N1, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

    Other_Citation_Details:
    Suggested Citation: Gibbs, A.E., Ohman, K.A., Coppersmith, R., and Richmond, B.M., 2017, National Assessment of Shoreline Change: A GIS compilation of updated vector shorelines and associated shoreline change data for the north coast of Alaska, U.S. Canadian border to Icy Cape (ver. 2.0, September 2024): U.S. Geological Survey data release, https://doi.org/10.5066/F72Z13N1.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -143.990143
    East_Bounding_Coordinate: -141.201885
    North_Bounding_Coordinate: 70.138283
    South_Bounding_Coordinate: 69.627939
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 1947
    Ending_Date: 2017
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector digital data (polyline)
  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 (2915)
    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 0.0000001. Longitudes are given to the nearest 0.0000001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is WGS_1984.
      The ellipsoid used is WGS 84.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257224.
  7. How does the data set describe geographic features?
    Attribute Table
    Table containing attribute information associated with the data set. (Source: U.S. Geological Survey)
    FID
    Internal feature number (Source: Esri) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry (Source: Esri) Coordinates defining the feature
    TransectID
    A permanent and unique identification number for each transect in the output rates table calculated by DSAS. (Source: Himmelstoss and others (2021)) Multiple unique numbers
    BaselineID
    Values in this field correlate to the baseline attribute field �ID� and are assigned by DSAS to identify the baseline segment used to generate the measurement transect. (Source: Himmelstoss and others (2021)) Multiple unique numbers
    GroupID
    Values in this field correlate to the optional baseline attribute field �DSAS_group� (Group_) and are assigned by DSAS if selected by user. This field is used to aggregate sections of the coast into groups. Here they represent coastal sub-region ID as defined in Gibbs and Richmond (2017). (Source: Himmelstoss and others (2021) and Gibbs and Richmond (2017))
    ValueDefinition
    1U.S. Canadian border to the Hulahula River
    TransOrder
    Assigned by DSAS based on ordering of transects along the baseline. Used to allow user to sort transect data along the baseline from baseline start to baseline end. (Source: U.S. Geological Survey)
    Range of values
    Minimum:1
    Maximum:3086
    Azimuth
    Used to record the azimuth of the transect measured in degrees clockwise from north. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.36
    Maximum:358.28
    ShrCount
    The total number of shorelines intersected by the transect and used for change analysis. (Source: U.S. Geological Survey)
    Range of values
    Minimum:3
    Maximum:5
    TCD
    Total cumulative distance in meters from start of baseline to transect location. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:216848.2
    SHAPE_Leng
    Length of transect in meter units. This field is automatically generated and maintained when data are within a geodatabase. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:unlimited
    SCE
    The shoreline change envelope (SCE) reports a distance, not a rate. The SCE is the distance between the shoreline farthest from and closest to the baseline at each transect. This represents the total change in shoreline movement for all available shoreline positions and is not related to their dates. (Source: U.S. Geological Survey)
    Range of values
    Minimum:2.78
    Maximum:290.07
    Units:Meters
    NSM
    The net shoreline movement (NSM) reports the distance between the oldest and youngest shorelines for each transect. This represents the total distance between the oldest and youngest shorelines. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-280.41
    Maximum:158.41
    Units:Meters
    LRR
    A linear regression rate-of-change statistic was calculated by fitting a least-squares regression line to all shoreline points for a particular transect. The best-fit regression line is placed so that the sum of the squared residuals (determined by squaring the offset distance of each data point from the regression line and adding the squared residuals together) is minimized. The linear regression rate is the slope of the line. The rate is reported in meters per year with positive values indicating accretion (shoreline advance) and negative values indicating erosion (shoreline retreat). (Source: U.S. Geological Survey)
    Range of values
    Minimum:-7.9
    Maximum:3.66
    LR2
    The R-squared statistic, or coefficient of determination, is the percentage of variance in the data that is explained by a regression. It is a dimensionless index that ranges from 1.0 to 0.0 and measures how successfully the best-fit line accounts for variation in the data. The smaller the variability of the residual values around the regression line relative to the overall variability, the better the prediction (and closer the R-squared value is to 1.0). (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:1
    LSE
    This quantity is the standard error of the regression, also known as the standard error of the estimate. To calculate it, the distance between each data point and the regression line is calculated. These distances are squared then summed. The sum is divided by the number of data point minus two. The square root is taken of the result. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.01
    Maximum:142.21
    LCI90
    The standard error of the slope with confidence interval describes the uncertainty of the reported rate. The LRR rates are determined by a best-fit regression line for the shoreline data at each transect. The slope of this line is the reported rate of change (in meters/year). The confidence interval (LCI) is calculated by multiplying the standard error (also called the standard deviation) of the slope by the two-tailed test statistic at the user-specified 90 percent confidence. This value is often reported in conjunction with the slope to describe the confidence of the reported rate. For example: LRR = 1.2 LCI90 = 0.7 could be reported as a rate of 1.2 (+/-) 0.7 meters/year. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:20.66
    ShoreType
    User defined shoreline type (Source: U.S. Geological Survey)
    ValueDefinition
    Sheltered MainlandA large, continuous extent of land that does not include offshore islands or other detached territories and is sheltered from direct wave energy by offshore islands.
    Sheltered Barrier SpitDeposits of sediment extending from the mainland into a body of water and sheltered from direct wave energy by offshore islands.
    Sheltered Barrier IslandDeposits of sediment that are detached from the coast, run parallel to the coastline, and are sheltered from direct wave energy by offshore islands.
    Sheltered Barrier BeachDeposits of sediment that run parallel to the coastline, are attached to the mainland at both ends, front a body of water, and are sheltered from direct wave energy by offshore islands.
    Sheltered IslandPortions of offshore islands sheltered from direct wave energy.
    CalcEras
    Decade or era of shorelines that were used to calculate shoreline change rates. (Source: U.S. Geological Survey) Multiple unique values listing the decades or eras of shorelines
    Entity_and_Attribute_Overview:
    The entity and attribute information provided here describes the tabular data associated with the data set. Please review the detailed descriptions that are provided (the individual attribute descriptions) for information on the values that appear as fields/table entries of the data set.
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Gibbs, Ann E.
    • Ohman, Karin A.
    • Coppersmith, Ryan
    • Richmond, Bruce M.
  2. Who also contributed to the data set?
    U.S. Geological Survey
  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?

Coastal erosion is a persistent process along most open-ocean shores of the United States and affects both developed and natural coastlines. Along the Arctic coast of Alaska, coastal erosion is widespread and threatens communities, defense and energy-related infrastructure, and coastal habitat. As the coast changes, there are a wide range of ways that change can affect coastal communities, habitats, and the physical characteristics of the coast-including beach erosion, shoreline retreat, land loss, and damage to infrastructure. The U.S. Geological Survey (USGS) is responsible for conducting research on coastal change hazards, understanding the processes that cause coastal change, and developing models to forecast future change. To understand and adapt to shoreline change, accurate information regarding the past and present configurations of the shoreline is essential and a comprehensive, nationally consistent analysis of shoreline movement is needed. To meet this national need, the USGS is conducting an analysis of historical shoreline changes along open-ocean coasts of the United States and parts of the Great Lakes. In Alaska, coastlines sheltered from open-ocean wave conditions by barrier islands are also included in the analysis because of their importance to defense and energy-related infrastructure and to understand the similarities, differences, and linkages in coastal behavior and physical processes acting on exposed and sheltered permafrost coastlines. This dataset is one in a series of regionally focused reports on historical shoreline change. As more data are gathered, periodic updates are made, which provide information that can be used in multidisciplinary assessments of global change impacts.

How was the data set created?

  1. From what previous works were the data drawn?
    DSAS baseline (source 1 of 2)
    U.S. Geological Survey, 2024, Midshore baseline for the sheltered eastern Beaufort Sea coast of Alaska (U.S. Canadian Border to the Hulahula River) generated to calculate shoreline change rates: U.S. Geological Survey, online.

    Online Links:

    Type_of_Source_Media: Digital Resources
    Source_Contribution:
    DSAS baseline, from this same data release, used for calculation of shoreline change rates.
    DSAS shoreline (source 2 of 2)
    U.S. Geological Survey, 2024, Shorelines from 1947 to 2017 for the East Beaufort Sea coast of Alaska (U.S. Canadian Border to the Hulahula River) used in shoreline change analysis: U.S. Geological Survey, online.

    Online Links:

    Type_of_Source_Media: Digital Resources
    Source_Contribution:
    DSAS shoreline file, from this same data release, used for calculation of shoreline change rates.
  2. How were the data generated, processed, and modified?
    Date: 2023 (process 1 of 4)
    Transect features were generated using DSAS v5.1 in ArcMap v10.8.1. Parameters Used: Baseline Layer= EastBeaufort_sheltered_baseline, Baseline ID Filed=ID, baseline placement=midshore, Baseline Orientation=Land is to the LEFT, Search Distance From Baseline=variable, Transect Spacing=50 meters, Smoothing Distance=500 meters. For additional details on these parameters, please see the DSAS help file distributed with the DSAS software, or visit the USGS website at: https://www.usgs.gov/centers/whcmsc/science/digital-shoreline-analysis-system-dsas. Data sources used in this process:
    • DSAS baseline
    Date: 2023 (process 2 of 4)
    Some transects were manually edited in ArcMap v10.8.1 to ensure they intersected all shorelines and were as close to perpendicular as possible.
    Date: 2023 (process 3 of 4)
    Rate calculations performed using DSAS v5.1 in ArcMap v10.8.1 on selected shoreline features. Parameters Used: Shoreline Layer= EastBeaufort_Shorelines, Shoreline Date Field=DATE_, Shoreline Uncertainty Field=Uncy, Default Data Accuracy=0 meters, Intersection Parameters=Seaward Intersection, Statistics to Calculate =[Shoreline Change Envelope (SCE)], [Net Shoreline Movement (NSM)],[Linear Regression Rate (LRR)], Confidence Interval=90 percent. For short-term rate calculations as subset of years (1979-2017) was selected. Data sources used in this process:
    • DSAS shoreline
    Date: 2024 (process 4 of 4)
    The exported transect shapefile was projected in Esri's ArcToolbox (v10.8.1) > Data Management Tools > Projections and Transformations > Feature > Project. Parameters: input projection � NAD_1983_2011_Alaska_Albers; output projection - geographic coordinates (WGS84); transformation = WGS_1984_(ITRF00)_To_NAD_1983.
  3. What similar or related data should the user be aware of?
    Gibbs, A.E., and B.M., Richmond, 2017, National Assessment of Shoreline Change: Summary Statistics for Updated Vector Shorelines and Associated Shoreline Change Data for the North Coast of Alaska, U.S.--Canadian Border to Icy Cape.

    Online Links:

    Other_Citation_Details:
    Gibbs, A.E., and Richmond, B.M., 2017, National Assessment of Shoreline Change: Summary Statistics for Updated Vector Shorelines and Associated Shoreline Change Data for the North Coast of Alaska, U.S.--Canadian Border to Icy Cape: U.S. Geological Survey Open-File Report 2017�1107, 21 p.
    Gibbs, Ann E., and Richmond, Bruce M., 2015, National Assessment of Shoreline Change--Historical Shoreline Change along the North Coast of Alaska, U.S.--Canadian Border to Icy Cape.

    Online Links:

    Other_Citation_Details:
    Gibbs, A.E., and Richmond, B.M., 2015, National assessment of shoreline change�Historical shoreline change along the north coast of Alaska, U.S.�Canadian border to Icy Cape: U.S. Geological Survey Open-File Report 2015�1048, 96 p.
    Himmelstoss, Emily A., Henderson, Rachel E., Kratzmann, Meredith G., and Farris, Amy S., 2021, Digital Shoreline Analysis System (version 5.1) User Guide.

    Online Links:

    Other_Citation_Details:
    Himmelstoss, E.A., Henderson, R.E., Kratzmann, M.G., and Farris, A.S., 2021, Digital Shoreline Analysis System (version 5.1) User Guide: U.S. Geological Survey Open-File Report 2021-1091.
    Himmelstoss, Emily A., Farris, Amy S., Henderson, Rachel E., Kratzmann, Meredith G., Ergul, Ayhan, Zhang, Ouya, Zichichi, Jessica L., and Thieler, E. Robert, 2018, Digital Shoreline Analysis System (version 5.1): U.S. Geological Survey Software.

    Online Links:

    Other_Citation_Details:
    Current software at time of use was 5.1. The second link directs to the DSAS project page.

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

  1. How well have the observations been checked?
    The attributes of this dataset are based on the field requirements of the Digital Shoreline Analysis System and were automatically generated by the software during the generation of the transect layer or during the calculation of shoreline change rates performed by the software. ShoreType and CalcEras attributes were added after rate calculations. The data have been quality checked.
  2. How accurate are the geographic locations?
    The transect serves as a reference point along which measurements are calculated by the Digital Shoreline Analysis System (DSAS) software. It does not correspond to any real-world feature. The uncertainty of the linear regression rate included with the transect file is estimated by the elements LR2, LSE and LCI90. See the attribute definition of each for more information.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    This dataset contains the transects automatically generated by the DSAS software application that were used to calculate shoreline change rates along sections of the north coast of Alaska, from the U.S.-Canadian border to the Hulahula River, where shoreline position data were available. Additional transects may have been generated but did not intersect the shoreline dates specified.
  5. How consistent are the relationships among the observations, including topology?
    These data were generated using DSAS v. 5.1, an automated software program which does not perform checks for fidelity of the input features. The transects were visually inspected and sometimes manually adjusted within a standard ArcMap edit session to adjust the position at which an individual transect intersected the shorelines. The data have been quality checked.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints No access constraints
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 - Science Base
    Denver Federal Center, Building 810, Mail Stop 302
    Denver, CO
    CA

    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?
    These data are available in a polyline shapefile format. The user must have software to read and process the data components of a shapefile.

Who wrote the metadata?

Dates:
Last modified: 12-Sep-2024
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_F72Z13N1/EastBeaufort_sheltered_LT_rates_v2.faq.html>
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