Alexander C. Seymour Kara S. Doran 20260310 1.0 vector digital data Alexander C. Seymour Kara S. Doran 20260310 U.S. Geological Survey data release doi:10.5066/P9WYA19U St. Petersburg, FL U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center https://doi.org/10.5066/P9WYA19U The U.S. Geological Survey (USGS) supports multiple efforts to understand and predict storm impacts to our nation's coastlines. The geospatial dataset (vector feature class) and comma-delimited American Standard Code for Information Interchange (ASCII) table describes a time series of modern foredune crest elevations and cross-shore positions across the North Carolina ocean-fronted coastline between September 1997 and October 2018. Beach width and slope statistics are additionally reported. Results are provided at an alongshore resolution of 500 meters (m) as a series of coincident points, with individual points describing dune and beach statistics derived from a particular topographic survey. Individual time series feature positions (points) represent the center of an alongshore “bin” and describe coastal topography statistics within 250 m alongshore on either side of the point. This data is intended as a companion to the dune condition codes provided in this same data release and are ideal for visualizing interannual changes in the dune crest and beach at individual locations. An ArcGIS Pro Map Package file is also included, which displays dune condition code and time series features with specific symbology and graphing schema that aid the user in interpreting and visualizing some of the most important attributes in the data. The methods used to generate this data followed the process outlined in “Decadal-scale characteristics of natural and anthropogenic dune morphology along North Carolina barrier islands (SE Atlantic coast)” by Seymour and others (2026). To provide information on the changes in the elevation and position of coastal dunes over the last two decades, along with beach width and slope data along the North Carolina coast. 19970915 20181002 ground condition Complete None planned -78.541634 -75.460637 36.546124 33.844975 USGS Metadata Identifier USGS:dc333550-0566-40e9-bb86-cdef7f663fe4 ISO 19115 Topic Category geoscientificInformation oceans environment structure USGS Thesaurus hazards marine geology ocean sciences coastal processes erosion floods geospatial datasets time series datasets None U.S. Geological Survey USGS St. Petersburg Coastal and Marine Science Center SPCMSC Coastal and Marine Hazards and Resources Program CMHRP Geographic Names Information System (GNIS) North Carolina Atlantic Ocean None Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. The U.S. Geological Survey requests to be acknowledged as originators of the data in future products or derivative research. U.S. Geological Survey Kara S. Doran mailing and physical

600 4th Street South

Saint Petersburg FL 33701 United States 727-502-8117 727-502-8001 kdoran@usgs.gov Windows 10 Enterprise 21H2 (Build 19044.1826); Esri ArcGIS Pro 2.7.1 Alexander C. Seymour Daniel J. Ciarletta Kara S. Doran Kai Parker Margaret L. Palmsten 20260305 Journal of Coastal Research Unknown https://doi.org/10.2112/JCOASTRES-D-25-00053.1 No formal accuracy assessment was conducted. This dataset is considered complete for the information presented, as described in the abstract section. Users are advised to read the rest of the metadata record carefully for additional details. No formal accuracy assessment is included. Horizontal positions were projected to the World Geodetic System of 1984 (WGS 84) Universal Transverse Mercator Zone 18 North (UTM 18N) coordinate system. No formal accuracy assessment is included. Vertical positions were referenced to the North American Vertical Datum of 1988 (NAVD88). Methods for deriving this data are described in Seymour and others (2026). Additionally, after time series features were generated, an analyst manually removed select points that occurred in inlets where the elevation of shoals was contributing datapoints to the time series. This sometimes occurred after the erosive loss of the subaerial beach and resulted in inaccurate dune elevation and migration change trends. Additional points were removed that were calculated from transects that diverged from shore-normal orientations. Specifically, this could occur most often directly on cape headlands or on spits adjoined to cape headlands. 20221013 NC_Time_Series_Features_GDB Alexander C. Seymour U.S. Geological Survey Physical Scientist mailing and physical

600 4th Street South

Saint Petersburg FL 33701 United States 727-502-8122 727-502-8001 aseymour@usgs.gov The data included in this release is a point feature class of time series features stored in a file geodatabase (.gdb), along with a comma-delimited ASCII table (.csv) for users that do not have the ability to open and view Geographic Information Systems (GIS) file formats. The time series ASCII table was generated by inputting the geodatabase feature classes into the ‘Feature Class to ASCII’ ArcGIS Pro geoprocessing tool. NC_Time_Series_Features_GDB 20221013 NC_Time_Series_Features_ASCII Alexander C. Seymour U.S. Geological Survey Physical Scientist mailing and physical

600 4th Street South

Saint Petersburg FL 33701 United States 727-502-8122 727-502-8001 aseymour@usgs.gov To include additional visualizations of the feature class data, an ArcGIS Pro Map Package (.mpkx) was generated, which contains specific symbolization of the feature classes and charts that aid the user in interpreting and visualizing some of the most important attributes in the data. The geodatabase feature classes, both the time series feature described in this metadata record (NC_Time_Series_Features_GDB), and the dune condition code (NC_Dune_Condition_Codes_GDB, described in NC_Dune_Condition_Code_Metadata) were added to a new ArcGIS Pro map. interactively symbolizing the features appropriately, and creating scatterplot and bar plot graph schema for the feature classes. The Hybrid Reference Layer and World Imagery basemaps were also added to the map layout. For more information about these basemaps, refer to: Hybrid Reference Layer (https://www.arcgis.com/home/item.html?id=30d6b8271e1849cd9c3042060001f425) and World Imagery (https://services.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer). The map and its associated schema were then exported to a Map Package by clicking the ‘New Map Package’ command in the ‘Share’ tab in ArcGIS Pro. NC_Dune_Condition_Codes_Time_Series.gdb NC_Time_Series_Features_GDB NC_Dune_Condition_Codes_GDB 20221013 NC_Dune_Condition_Codes_Time_Series_Map_Pack.mpkx NC_Dune_Condition_Codes_Time_Series.zip Alexander C. Seymour U.S. Geological Survey Physical Scientist mailing and physical

600 4th Street South

Saint Petersburg FL 33701 United States 727-502-8122 727-502-8001 aseymour@usgs.gov Point Point 10172 Universal Transverse Mercator 18N 0.9996 -75.0 0.0 500000.0 0.0 coordinate pair 0.001 0.001 meters WGS 1984 WGS 1984 6378137.0 298.257223563 North American Vertical Datum 1988 0.01 meters Attribute values NC_Time_Series_Features_GDB, NC_Time_Series_Features_ASCII.csv File geodatabase feature class (.gdb) and comma-separated values file (.csv) of the time series features for North Carolina. USGS OBJECTID Internal feature number. Esri Sequential unique whole numbers that are automatically generated. Shape Feature geometry. This attribute is only present in the feature class dataset. Esri Vector type (Point M). AlongshoreID Unique ID for the alongshore bin. USGS 1 1033 MeanDuneElevation Average dune crest elevation within each alongshore bin, in meters NAVD88. Null values indicate an individual survey where there were too few dune crest elevation samples found within the 500 m bin to estimate a mean. USGS 0.594267 10.441828 DuneElevationSTD Dune crest elevation standard deviation within each alongshore bin, in meters. Null values indicate an individual survey where there were too few dune crest elevation samples within a 500 m bin to estimate a standard deviation. USGS 0 3.500049 MeanDunePosition The mean cross-shore position of the dune crest within each bin relative to the earliest dune crest position mean in the time series, in meters. Negative numbers indicate positions landward of the earliest dune crest. Null values indicate an individual survey where there were too few dune cross shore position samples within a 500 m bin to estimate a mean. USGS -674.594666 434.85025 DunePositionSTD Dune crest cross-shore position standard deviation within each alongshore bin, in meters. Null values indicate an individual survey where there were too few dune cross shore position samples within a 500 m bin to estimate a standard deviation. USGS 0 367.658533 MeanShorelinePosition Mean high water shoreline position within each alongshore bin relative to the earliest shoreline position mean in the time series, in meters. Negative numbers indicate positions landward of the earliest shoreline. Null values indicate an individual survey where there were too few shoreline position samples within a 500 m bin to estimate a mean. USGS -708.433594 671.80412231 MeanBeachWidth Average beach width within each alongshore bin, in meters. Null values indicate an individual survey where there were too few beach width samples within a 500 m bin to estimate a mean. USGS 6.960783 752.538513 MeanBeachSlope Average beach slope within each alongshore bin, in angular degrees. Null values indicate an individual survey where there were too few beach slope samples within a 500 m bin to estimate a mean. USGS 0.155839 14.707931 DuneCrestSampleSize The number of transects in an alongshore bin with valid dune elevation measurements. USGS 0 68 ShorelineSampleSize The number of transects in an alongshore bin with valid shoreline position measurements. USGS 0 70 SurveyYear The year of the survey from which dune and shoreline features were derived. USGS 1997 2018 SurveyDate String recording the date (MM/DD/YYYY) of the survey from which dune and shoreline features were derived. USGS 09/15/1997 10/2/2018 Overview_Description: XCoord Easting (x) coordinate (WGS 84 UTM 18N). USGS 172289.1866 458262.4674 YCoord Northing (y) coordinate (WGS 84 UTM 18N). USGS 3748925.4136 4044873.0271 NC_Dune_Condition_Codes_Time_Series_Map_Pack.mpkx: ArcGIS Pro Map Package containing the dune condition codes (NC_Dune_Condition_Codes) and time series features (NC_Time_Series_Features) feature classes, stored inside a file geodatabase (NC_Dune_Condition_Codes_Time_Series.gdb). The Map Package also contains the Hybrid Reference Layer and World Imagery basemaps published by Esri in the Living Atlas. These basemaps are accessible via ArcGIS Online: Hybrid Reference Layer (https://www.arcgis.com/home/item.html?id=30d6b8271e1849cd9c3042060001f425) and World Imagery (https://services.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer). Scatterplots in the map pack are designed to only display plots from singular condition code points selected by the user. The user must bandbox select a desired condition code point with the Select interactive tool for a scatterplot to display data. The entity and attribute information were generated by the individual and/or agency identified originator of the dataset. Please review the metadata records associated with this data release for additional details and information. U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center USGS SPCMSC Data Management mailing and physical

600 4th Street South

Saint Petersburg FL 33701 United States 727-502-8000 gs-g-spcmsc_data_inquiries@usgs.gov NC_Dune_Time_Series_GDB.gdb, NC_Dune_Time_Series_ASCII.csv, NC_Dune_Condition_Codes_Time_Series_Map_Pack.mpkx This digital publication was prepared by an agency of the United States Government. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, nor shall the act of distribution imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. comma-delimited text, file geodatabase (Esri), ArcGIS Pro Map Package ArcGIS Pro 3.0.3 https://coastal.er.usgs.gov/data-release/doi-P9WYA19U/data/NC_Dune_Condition_Codes_Time Series.zip None The geodatabase feature class and ArcGIS Map Package were created for the use within Esri ArcGIS Pro software (3.0.3 or newer). The ASCII table data were created for the use within Microsoft Excel, or similar text viewers, such as Notepad. 20260310 U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center USGS SPCMSC Data Management mailing and physical

600 4th Street South

Saint Petersburg FL 33701 United States 727-502-8000 gs-g-spcmsc_data_inquiries@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998 local time