shoreline, inletLines: Shoreline polygons and tidal inlet delineations: Cape Hatteras, NC, 2014

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Frequently anticipated questions:

What does this data set describe?

Title:
shoreline, inletLines: Shoreline polygons and tidal inlet delineations: Cape Hatteras, NC, 2014
Abstract:
Understanding how sea-level rise will affect coastal landforms and the species and habitats they support is critical for crafting approaches that balance the needs of humans and native species. Given this increasing need to forecast sea-level rise effects on barrier islands in the near and long terms, we are developing Bayesian networks to evaluate and to forecast the cascading effects of sea-level rise on shoreline change, barrier island state, and piping plover habitat availability. We use publicly available data products, such as lidar, orthophotography, and geomorphic feature sets derived from those, to extract metrics of barrier island characteristics at consistent sampling distances. The metrics are then incorporated into predictive models and the training data used to parameterize those models. This data release contains the extracted metrics of barrier island geomorphology and spatial data layers of habitat characteristics that are input to Bayesian networks for piping plover habitat availability and barrier island geomorphology. These datasets and models are being developed for sites along the northeastern coast of the United States. This work is one component of a larger research and management program that seeks to understand and sustain the ecological value, ecosystem services, and habitat suitability of beaches in the face of storm impacts, climate change, and sea-level rise.
Supplemental_Information:
This metadata file describes two related datasets. Full methods are provided in the associated USGS Open-File Report (Zeigler and others, 2019).
  1. How might this data set be cited?
    Sturdivant, Emily J., Zeigler, Sara L., and Gutierrez, Benjamin T., 20191220, shoreline, inletLines: Shoreline polygons and tidal inlet delineations: Cape Hatteras, NC, 2014: data release DOI:10.5066/P9V7F6UX, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Sturdivant, Emily J., Zeigler, Sara L., Gutierrez, Benjamin T., and Weber, Kathryn M., 2019, Barrier island geomorphology and shorebird habitat metrics: Sixteen sites on the U.S. Atlantic Coast, 2013–2014: data release DOI:10.5066/P9V7F6UX, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Sturdivant, E.J., Zeigler, S.L., Gutierrez, B.T., and Weber, K.M., 2019, Barrier island geomorphology and shorebird habitat metrics—Sixteen sites on the U.S. Atlantic Coast, 2013–2014: U.S. Geological Survey data release, https://doi.org/10.5066/P9V7F6UX.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -76.0188915
    East_Bounding_Coordinate: -75.46194418
    North_Bounding_Coordinate: 35.7742004
    South_Bounding_Coordinate: 35.06624563
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/5daa3767e4b09fd3b0c9ce6b/?name=shoreline_asis_browse.png (PNG)
    Example shoreline polygon (blue) and inlet delineation (red). This example is from Assateague Island, VA and may not represent this dataset.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: Nov-2013
    Ending_Date: Jun-2014
    Currentness_Reference:
    Ground condition measured by source lidar data.
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector digital dataset (polyline)
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 18
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -75
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000.0
      False_Northing: 0.0
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.6096
      Ordinates (y-coordinates) are specified to the nearest 0.6096
      Planar coordinates are specified in Meter
      The horizontal datum used is D_North_American_1983.
      The ellipsoid used is GRS_1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257222101.
  7. How does the data set describe geographic features?
    caha14_inletLines attribute table
    Attribute values for polylines delineating tidal inlets (caha14_inletLines.shp). (Source: Producer defined)
    FID
    Internal feature number (Source: Esri) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: Esri) Coordinates defining the features.
    Shape_Leng
    Length of the feature automatically calculated by ArcGIS 10.5, incorporating the projected coordinate system. (Source: Producer defined)
    Range of values
    Minimum:570.813478
    Maximum:5657.834744
    Units:meters
    caha14_shoreline attribute table
    Attribute values for polygons delineating shoreline (caha14_shoreline.shp). (Source: Producer defined)
    FID
    Internal feature number (Source: Esri) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: Esri) Coordinates defining the features.
    Shape_Area
    Area of the feature in square meters automatically calculated by ArcGIS 10.5 incorporating the projected coordinate system. (Source: Producer defined)
    Range of values
    Minimum:7854.549303
    Maximum:83316213.43
    Units:square meters

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Emily J. Sturdivant
    • Sara L. Zeigler
    • Benjamin T. Gutierrez
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Sara L. Zeigler
    U.S. Geological Survey
    384 Woods Hole Road
    Woods Hole, MA
    USA

    508-548-8700 x2290 (voice)
    (508) 457-2310 (FAX)
    szeigler@usgs.gov

Why was the data set created?

The shoreline polygons (caha14_shoreline.shp) are a generalized delineation of the mean high water (MHW) position on the seaward face of the barrier and mean tidal level (MTL, average of MHW and mean low water) position on the inland face. They delineate the shoreline for the purposes of this study. These polygons were used to convert the transects to 5-m points and to measure island width, distance to inlet from each transect, and position of the shoreline (see larger work). In addition, the inlet delineation polylines (caha14_inletLines.shp) use single straight line segments to roughly locate each side of tidal inlets for the barrier study area. These lines were used (1) to designate the transition between ocean-facing and land-facing sides of the barrier and (2) to measure the distance to tidal inlet in the 5-m points dataset (see larger work). They were created manually to cross the MHW contour line on each side of a tidal inlet within the study area.

How was the data set created?

  1. From what previous works were the data drawn?
    DEM (source 1 of 1)
    Department of Commerce (DOC), National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), National Geodetic Survey (NGS), Remote Sensing Division, and Department of Commerce (DOC), National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), Office for Coastal Management (OCM), 20151220, 2014 NOAA Post-Sandy Topobathymetric LiDAR: Void DEMs South Carolina to New York: NOAA's Ocean Service, National Geodetic Survey (NGS), Silver Spring, MD.

    Online Links:

    Type_of_Source_Media: digital data
    Source_Contribution:
    Elevation. Source data were downloaded from https://coast.noaa.gov/dataviewer in horizontal datum NAD 1983 (2011), UTM Zone 18N, vertical datum NAVD88. Downloaded on 4/8/2016.
  2. How were the data generated, processed, and modified?
    Date: 2018 (process 1 of 3)
    Full methods are provided in the associated Methods OFR (Zeigler and others, 2019).
    caha14_shoreline.shp:
    A polygon outlining the shoreline of the barrier was created for the study area. On the ocean-facing side, this was considered the MHW contour (Weber and others, 2005, Zeigler and others, 2019). To include partially submerged wetland on the estuarine-side, the land-facing shoreline was delineated at mean tidal level (MTL), which was calculated from the local MHW and mean low water (MLW) levels at the given study area.
    The local MLW elevation was estimated from NOAA’s VDatum (2014 release) as the average MLW elevation at a sample of nearshore points in the study area. Experimentation conducted as part of this study found that the MTL delineation more consistently identified the boundary between marsh (intertidal vegetation) and submerged areas than either MHW or MLW. For consistency with the MHW offset applied throughout the project, MHW was used as part of the calculation of MTL.
    To create this shoreline, we performed the following steps. Most of the steps were performed programmatically using the function functions_warcpy.DEMtoFullShorelinePoly in bi-transect-extractor (Sturdivant, 2019):
    1. Convert the shoreline points CSV to a multipoint feature class in reference system NAD_1983_UTM_Zone_18N. This was performed in ArcGIS 10.5 using the tools Make XY Event Layer and Project. The datum transformation used was WGS_1984_(ITRF00)_To_NAD_1983 (WKID: 108190, accuracy: 0.1 m).
    2. Manually digitize lines from the DEM that indicate where land meets a tidal inlet, which is considered the division point between the oceanside and the bayside or estuarine side of the barrier. This line was visually approximated.
    3. Create a generalized polygon from the DEM in which every cell within the polygon is above MHW (MHW polygon). This was performed programmatically using the function functions_warcpy.RasterToLandPerimeter in bi-transect-extractor v1.0 (Sturdivant, 2019) with a MHW elevation of 0.26 m NAVD88, calculated for the area by Weber and others (2005). The process includes generalizing the polygons (Aggregate Polygons tool in the Cartography toolbox) using an aggregation distance of 10 m, a minimum area of 300 m2, and a minimum hole size of 300 m2.
    4. Repeat Step 3 for MTL, using an MTL elevation of -0.095 m NAVD88.
    5. Merge the polygons so that the MHW contour outlines the barrier on the oceanside and the MTL contour outlines the bayside (if a bayside shoreline exists), divided at the delineated tidal inlets. To do so, create a symmetrical difference polygon between MHW and MTL polygons (SymDiff) and split the resulting polygon at the inlet lines (Feature to Polygon). Create a polygon that outlines only the bayside area that is above MTL and below MHW (MTL-only polygon) by deleting the segments of the symmetrical difference polygon that overlap shoreline points (Spatial Join, Erase). Merge the MTL-only polygon with the MHW polygon (Union, Dissolve). This was performed using the function functions_warcpy.CombineShorelinePolygons in bi-transect-extractor (Sturdivant, 2019).
    6. Adjust the vertices of the polygons to precisely match the MHW shoreline positions wherever they are within 25 m of each other (Doran and others, 2017). This was performed using the function functions_warcpy.NewBNDpoly in bi-transect-extractor (Sturdivant, 2019). That snaps the polygon to the shoreline points where it is within 25 m of a point (Snap tool in the Edit toolbox, ArcGIS 10.5).
    7. QA/QC the output and manually revise any sections where the point snapping created clearly incorrect artifacts.
    The dataset contains 9 polygons. Person who carried out this activity:
    Emily J. Sturdivant
    U.S. Geological Survey
    Geographer
    384 Woods Hole Road
    Woods Hole, MA
    USA

    508-548-8700 x2230 (voice)
    508-457-2310 (FAX)
    esturdivant@usgs.gov
    Date: 2018 (process 2 of 3)
    Full methods are provided in the associated Methods OFR (Zeigler and others, 2019). The Jupyter notebook used for processing is distributed with the larger work dataset in IPYNB format (extractor_caha14.ipynb).
    caha14_inletLines.shp
    Display the DEM with a color break at mean high water (MHW) elevation. Manually digitize a straight line that bisects MHW where the seaward shoreline meets a tidal inlet, which is also considered the division point between the ocean-side and bay- or estuarine-side of the barrier. This line was visually approximated. The dataset contains 5 polylines.
    Date: 10-Aug-2020 (process 3 of 3)
    Added keywords section with USGS persistent identifier as theme keyword. 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
  3. What similar or related data should the user be aware of?
    Zeigler, Sara L., Sturdivant, Emily J., and Gutierrez, Benjamin T., 2019, Evaluating barrier island characteristics and piping plover (Charadrius melodus) habitat availability along the U.S. Atlantic coast—Geospatial approaches and methodology: Open-File Report 2019–1071, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Details the methods used to process these data for use in barrier island and piping plover habitat modeling.
    Sturdivant, Emily J., 2019, bi-transect-extractor: software release DOI:10.5066/P915UYMY, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Custom-built package used for data processing. The Jupyter notebook file distributed with these data was part of the processing to create these data. The notebook relies on this software package.
    Doran, Kara J., Long, Joseph W., Birchler, Justin J, Brenner, Owen T., Hardy, Matthew W., Karen L. M. Morgan, Stockdon, Hilary F., and Torres, Miguel L., 2017, Lidar-derived Beach Morphology (Dune Crest, Dune Toe, and Shoreline) for U.S. Sandy Coastlines: U.S. Geological Survey, Reston, VA.

    Online Links:

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

  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
    Positional accuracy is dependent on the accuracy of the input datasets (DEM and shoreline points) and on the generalization routines used to create these polygons. For any given section of shoreline, these outlines (caha14_shoreline.shp) are assumed to be accurate within 25 m. However, the assumed accuracy along the seaward face of the barrier is much greater. For the greatest shoreline accuracy, refer to the shoreline points (caha14_SLpts.shp in larger work). The assumed positional accuracy of the inlet polyline(s) is 5 m.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    The shoreline polygon(s) (caha14_shoreline.shp) represent a generalized outline of the land above water. The data should not be used for any purpose that requires precision or accuracy, such as navigation or engineering. The polygon(s) along the inland side of the study area may not be representative of the back-barrier shoreline, such as where the barrier adjoins the mainland and where the elevation data do not have enough coverage to include the back-barrier shoreline. The inlet polyline(s) (caha14_inletLines.shp) locate all points where the barrier beach alongshore shoreline is broken. If one side of an inlet was not within the study area, that side was not delineated.
  5. How consistent are the relationships among the observations, including topology?
    The shoreline shapefile (caha14_shoreline.shp) consists of polygon data produced from elevation data and tidal datum values through an automated process described below. The inlet delineation shapefile (caha14_inletLines.shp) consists of manually created line data. No checks for topological consistency were performed on these data.

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 Not to be used for navigation. Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information.
  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
    USA

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? This dataset contains two individual datasets: The shoreline dataset contains an Esri polygon shapefile (caha14_shoreline.shp and other shapefile components), and the inlet delineation dataset contains an Esri shapefile (caha14_inletLines.shp and other shapefile components). The CSDGM FGDC metadata describing the two datasets in XML format (caha14_shoreline_inletLines_meta.xml) and the browse graphic (shoreline_asis_browse.png, illustrating a similar dataset from another part of the U.S. Atlantic coast) are also included. These datasets can be downloaded individually or packaged on-demand in a zip file (see the Digital Transfer Option section).
  3. What legal disclaimers am I supposed to read?
    Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. 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 have been processed successfully on a computer system at the USGS, no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  4. How can I download or order the data?
  5. What hardware or software do I need in order to use the data set?
    To utilize these data, the user must have software capable of reading shapefile format, or GIS software capable of utilizing web mapping or feature services.

Who wrote the metadata?

Dates:
Last modified: 19-Mar-2024
Metadata author:
Sara L. Zeigler
U.S. Geological Survey
384 Woods Hole Road
Woods Hole, MA
USA

508-548-8700 x2290 (voice)
(508) 457-2310 (FAX)
whsc_data_contact@usgs.gov
Contact_Instructions:
The metadata contact email address is a generic address in the event the person is no longer with USGS. (updated on 20240319)
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/SB_data_release/DR_P9V7F6UX/caha14_shoreline_inletLines_meta.faq.html>
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