Ann E. Gibbs Alexander G. Snyder Nora M. Nieminski 20260102 vector digital data (polyline) data release 10.5066/P1RYHDR7 U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz U.S. Geological Survey, Coastal and Marine Geology Program https://doi.org/10.5066/P1RYHDR7 Ann E. Gibbs Alexander G. Snyder Nora M. Nieminski 2026 data release 10.5066/P1RYHDR7 Pacific Coastal and Marine Science Center, Santa Cruz, CA U.S. Geological Survey Suggested Citation: Gibbs, A.E., Snyder, A.G., Nieminski, N.M., 2026, National assessment of shoreline change: A GIS compilation of vector shorelines (1949 – 2015) and associated shoreline change data for the west coast of Alaska, Cape Prince of Wales to Kotlik River: U.S. Geological Survey data release, https://doi.org/10.5066/P1RYHDR7. https://doi.org/10.5066/P1RYHDR7 This dataset consists of short-term (less than 40 years) shoreline change rates for the west coast of Alaska between Cape Prince of Wales and the Kotlik River. Rate calculations were computed within a GIS using the Digital Shoreline Analysis System (DSAS) version 5.1.2, an ArcGIS extension developed by the U.S. Geological Survey. Short-term rates of shoreline change were calculated using an end-point method based on available shoreline data between 1980 and 2015. 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. Coastal erosion is a persistent process along most open-ocean shores of the United States and affects both developed and natural coastlines. Along the coast of Alaska, coastal erosion is widespread and threatens communities, infrastructure, and coastal habitat. As the coast changes, there are many 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. 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 coastal change hazards. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the Alaska Division of Geological & Geophysical Surveys or 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. 1980 2015 ground condition Complete None planned -168.0948 -160.4740 65.5317 62.9810 ISO 19115 Topic Category oceans environment geoscientificInformation Data Categories for Marine Planning Distributions Physical/Chemical Features USGS Thesaurus coastal processes geospatial datasets Marine Realms Information Bank (MRIB) keywords shoreline accretion shoreline erosion None U.S. Geological Survey USGS Coastal and Marine Hazards and Resources Program CMHRP Pacific Coastal and Marine Science Center PCMSC Shoreline Shoreline change Digital Shoreline Analysis System DSAS USGS Metadata Identifier USGS:68bf6e91d4be023bd943d3e8 Geographic Names Information System (GNIS) State of Alaska Bering Sea Norton Sound Brevig Mission Teller Nome Golovin Shaktoolik Unalakleet Stebbins Saint Michael None United States of America Alaska No access 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. These data are marked with a Creative Common CC BY 4.0 License, and users must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. Please recognize and acknowledge the U.S. Geological Survey and the Alaska Division of Geological & Geophysical Surveys as the originators of the dataset and in products derived from these data. U.S. Geological Survey, Pacific Coastal and Marine Science Center PCMSC Science Data Coordinator mailing and physical

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Santa Cruz CA 95060 831-427-4747 pcmsc_data@usgs.gov Emily A. Himmelstoss Rachel E. Henderson Meredith G. Kratzmann Amy S. Farris 2021 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. https://doi.org/10.3133/ofr20211091 https://www.usgs.gov/centers/whcmsc/science/digital-shoreline-analysis-system-dsas Emily A. Himmelstoss Amy S. Farris Rachel E. Henderson Meredith G. Kratzmann Ayhan Ergul Ouya Zhang Jessica L. Zichichi E. Robert Thieler 2018 Current software at time of use was 5.1. The second link directs to the DSAS project page. https://code.usgs.gov/cch/dsas/-/tree/v5.1?ref_type=tags https://www.usgs.gov/centers/whcmsc/science/digital-shoreline-analysis-system-dsas 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 attributes were added after rate calculations. The data have been quality checked. These data were generated using DSAS version 5.1.2. The transects automatically generated by the software were visually inspected along with the shoreline data prior to rate calculations. Sometimes transect positions were manually edited within a standard ArcMap edit session to adjust the position at which an individual transect intersected the shorelines to better represent an orthogonal position to the general trend of the coast over time. This dataset contains the transects automatically generated by the DSAS software application that were used to calculate shoreline change rates along sections of the west coast of Alaska, between Cape Prince of Wales and the Kotlik River, where shoreline position data were available. Additional transects may have been generated but did not intersect the shoreline dates specified. 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. U.S. Geological Survey 2025 shapefile online U.S. Geological Survey https://doi.org/10.5066/P1RYHDR7 Digital Resources 2025 publication date DSAS baselines DSAS baselines used for calculation of shoreline change rates, available from this same data release.. U.S. Geological Survey 2025 shapefile online U.S. Geological Survey https://doi.org/10.5066/P1RYHDR7 Digital Resources 1949 2015 ground condition DSAS shoreline DSAS shoreline file used for calculation of shoreline change rates, available from this same data release. Transect features were generated using DSAS v5.1.2 in ArcMap v10.8.1. Parameters Used: Baseline Layer=NorthwestAK_baselines, Baseline ID Field=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. 2024 Some transects were manually edited to ensure they intersected all shorelines and were as close to perpendicular as possible. 2024 Rate calculations performed using DSAS v5.1.2 in ArcMap v10.8.1 on selected shoreline features. Parameters Used: Shoreline Layer= NorthwestAK_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)], [End-point Rate (EPR)], Confidence Interval=90 percent, producing rates and intersect points. 2025 The transect feature class was exported from a personal geodatabase to a shapefile in ArcCatalog v10.8.1 by performing a right-mouse click on the data layer > export > to shapefile (single). 2025 BestRate, BestUNCY, and RateType fields were added to the shapefile. BestRate was calculated as EPR where ShrCount=2 and LRR where ShrCount=3. BestUNCY was calculated as EPRUncy where ShrCount=2 and LCI90 where ShrCount=3.RateType was calculated as EPR where ShrCount=2 and LRR where ShrCount=3. 2025 The exported shoreline shapefile was reprojected in Esri's ArcGIS Pro v3.4.3 > Data Management Tools > Projections and Transformations > Project. Parameters: input projection = NAD 1983 UTM Zone 3N; output projection = geographic coordinates (WGS84); transformation = WGS_1984_(ITRF00)_To_NAD_1983. 2025 The exported and edited transect shapefile was projected in Esri's ArcGIS Pro v3.4.3 ) > Data Management Tools > Projections and Transformations > Feature > Project. Parameters: input projection – NAD 1983 UTM Zone 3N); output projection - geographic coordinates (WGS84); transformation = WGS_1984_(ITRF00)_To_NAD_1983. 2025 The metadata title was modified to move the location to the beginning of the title. This was done to meet new system requirements as ScienceBase is migrated to a new platform, and to keep datasets grouped by location on the new data release landing page. (20260327). 20260327 Manda Au U.S. Geological Survey Data Management Specialist Mailing

2885 Mission Street

Santa Cruz CA 95060 831-460-7575 mau@usgs.gov Vector String 16431 0.0000001 0.0000001 Decimal seconds D_WGS_1984 WGS_1984 6378137.0 298.257223563 Attribute Table Table containing attribute information associated with the dataset. Producer defined FID Internal feature number Esri Sequential unique whole numbers that are automatically generated. Shape Feature geometry Esri Polyline ZM ESRI polyline shapefile Esri TransectID A permanent and unique identification number for each transect in the output rates table calculated by DSAS. Himmelstoss and others (2018) 223 22153 Unitless 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. Himmelstoss and others (2018) 1 40 Unitless TransOrder Assigned by DSAS based on ordering of transects along the baseline or baselines. If the user manually adds transects to the file in an edit session, they will be added to the end of the transect attribute table and given a new TransectID (ObjectID). However, TransOrder will be updated to reflect the position of the new transect with respect to the other transects along the baseline. This field provides the user with a method to sort transect attribute data from the start of the baseline segment with an ID=1 and increment by one alongshore to the end of the final baseline segment. Himmelstoss and others (2018) 223 22153 Unitless Azimuth Used to record the azimuth of the transect measured in degrees clockwise from north. Himmelstoss and others (2018) 0 360 Degrees ShrCount The total number of shorelines intersected by the transect and used for change analysis. Himmelstoss and others (2018) 2 2 Number of shorelines TCD Total cumulative distance in meters from start of baseline to transect location. U.S. Geological Survey 11100.00 1162943.01 Meters SCE The shoreline change envelope (SCE) reports a distance, not a rate. The SCE is the distance between the most seaward and most landward shoreline at each transect. This represents the total change in shoreline movement for all available shoreline positions and is not related to their dates. Himmelstoss and others (2018) 0 402.49 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. If this distance is divided by the number of years elapsed between the two shoreline positions, the result is the End Point Rate (EPR). Himmelstoss and others (2018) -401.90 402.49 Meters EPR End-point rate Himmelstoss and others (2018) -11.45 11.50 meters per year EPRunc Uncertainty of the end point rate Himmelstoss and others (2018) 0.15 0.27 meters per year SHAPE_Leng Length of transect in meter units, assuming data were properly projected in a meter-based coordinate system. This field is automatically generated and maintained when data are within a geodatabase. Himmelstoss and others (2018) 89.69 864.70 Meters The entity and attribute information provided here describes the tabular data associated with the dataset. 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 dataset. The entity and attribute information were generated by the individual and/or agency identified as the originator of the dataset. Please review the rest of the metadata record for additional details and information. U.S. Geological Survey - ScienceBase mailing and physical address

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 CA 888-275-8747 sciencebase@usgs.gov These data are available in shapefile format contained in a single zip file, which also includes CSDGM FGDC-compliant metadata. 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) and the Alaska Division of Geological & Geophysical Surveys (DGGS), 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. Shapefile ArcGIS Pro v3.4.3 Esri polyline shapefile Zip file contains shoreline change rates measured along shore perpendicular transects on the northwest coast of Alaska and associated metadata. Use WinZip or equivalent 1.16 https://doi.org/10.5066/P1RYHDR7 Data can be downloaded using the Network_Resource_Name link and selecting the specific Child Items title page. None. These data are available in a polyline shapefile format. The user must have software to read and process the data components of a shapefile. 20260327 U.S. Geological Survey, Pacific Coastal and Marine Science Center PCMSC Science Data Coordinator mailing and physical

2885 Mission Street

Santa Cruz CA 95060 831-427-4747 pcmsc_data@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998