Barrier island geomorphology and seabeach amaranth metrics at 50-m alongshore transects, and 5-m cross-shore points for 2008 — Assateague Island, MD and VA.

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What does this data set describe?

Title:
Barrier island geomorphology and seabeach amaranth metrics at 50-m alongshore transects, and 5-m cross-shore points for 2008 — Assateague Island, MD and VA.
Abstract:
Understanding how sea-level rise will affect coastal landforms and the species and habitats they support is critical for developing 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 effects of sea-level rise on shoreline change, barrier island geomorphology, and habitat availability for species such as piping plover (Charadrius melodus) and seabeach amaranth (Amaranthus pumilus). We use publicly available data products, such as lidar, orthophotography, and vegetation/substrate maps to extract metrics of barrier island characteristics for Assateague Island National Seashore. The metrics are used to conduct statistical analyses and used to training and test probabilistic models developed for barrier island systems. This data release contains the extracted metrics of barrier island geomorphology, and field collected species information (amaranth) that are input to Bayesian networks to evaluate the occurrence probabilities for a suite of barrier island characteristics and ultimately habitat suitability. While the data presented here samples conditions at Assateague Island National Seashore in 2008, this work is one component of a larger research and management program that seeks to understand the future states of barrier island systems and resulting impacts to coastal habitat driven by sea-level rise.
Supplemental_Information: Transect point data are available in tabular (.csv) format
  1. How might this data set be cited?
    Gutierrez, Benjamin T., Turecek, Aaron, Lentz, Erika E., Thieler, E. Robert, Plant, Nathaniel G., Henderson, Rachel E., and Sterne, Travis K., 20230426, Barrier island geomorphology and seabeach amaranth metrics at 50-m alongshore transects, and 5-m cross-shore points for 2008 — Assateague Island, MD and VA.: data release DOI:10.5066/P9GKXN3H, 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.

    Gutierrez, Benjamin T., Heslin, Julia L., Sturdivant, Emily J., Henderson, Rachel E., and Sterne, Travis K., 2023, Seabeach amaranth presence-absence and barrier island geomorphology metrics as relates to shorebird habitat for Assateague Island National Seashore — 2008, 2010, and 2014: data release DOI:10.5066/P9GKXN3H, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Gutierrez, B.T., Heslin, J.L., and Sturdivant, E.J., 2023, Seabeach amaranth presence-absence and barrier island geomorphology metrics as relates to shorebird habitat for Assateague Island National Seashore — 2008, 2010, and 2014: U.S. Geological Survey data release, https://doi.org/10.5066/P9GKXN3H.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -75.40016632
    East_Bounding_Coordinate: -75.09260865
    North_Bounding_Coordinate: 38.32471091
    South_Bounding_Coordinate: 37.85164672
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/61c1f949d34eafc738ca042f?name=ASIS_transect_points.jpg (JPEG)
    Example view (top panel) of the 5-m points (black), which follow the cross-shore transects (yellow) and diagram (bottom panel) of the metrics computed at each transect point.
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2008
    Currentness_Reference:
    Ground condition measured by source data for given attribute as specified in process steps.
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: tabular data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Entity Point (263,724)
    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.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: North American Vertical Datum of 1988 (NAVD88)
      Altitude_Resolution: 0.001
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method: Attribute values
  7. How does the data set describe geographic features?
    asis2008_pts.csv
    Geomorphology metrics at 263,724 discrete points along shore-normal transects. Transect-averaged values are also included. For enumerated domains (e.g. Human_modV2, HabNPS, VegRech), these metadata list all possible values although all values described may not be present in this dataset. (Source: U.S. Geological Survey)
    pID
    Sequential unique whole numbers that identify each point in the dataset, organized first by order along shore (from the field 'TRANSORDER'), and then by distance to MHW (from the field dist2MHW). (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:263724
    seg_x
    Point easting referenced to UTM Zone 18N NAD 83. NoData value of -99999 occurs where the source transect did not intersect land, which results in a record without location. (Source: U.S. Geological Survey)
    Range of values
    Minimum:464806.90
    Maximum:491905.00
    Units:meters
    seg_y
    Point northing referenced to UTM Zone 18N NAD 83. NoData value of -99999 occurs where the source transect did not intersect land, which results in a record without location. (Source: U.S. Geological Survey)
    Range of values
    Minimum:4189424.20
    Maximum:4241847.90
    Units:meters
    Longitude
    Longitude in NAD 83. Negative values indicate western hemisphere. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-75.4002
    Maximum:-75.0926
    Units:decimal degrees
    Latitude
    Latitude in NAD 83 (Source: U.S. Geological Survey)
    Range of values
    Minimum:37.8516
    Maximum:38.3230
    Units:decimal degrees
    dist2MHW
    Along-transect distance to the mean high water (MHW) shoreline position. (Source: U.S. Geological Survey)
    Range of values
    Minimum:1.6
    Maximum:3637.2
    Units:meters
    dist2MHWBay
    Distance to the back-barrier shoreline from the transect point location. (Source: U.S. Geological Survey)
    Range of values
    Minimum:1.6
    Maximum:3637.2
    Units:meters
    TRANSORDER
    The TRANSORDER, or transect order, value is assigned by the Digital Shoreline Analysis System (DSAS) software based on ordering of transects alongshore. Value given to original transects (NASC transects), and appended to subsequent transect and transect point data. (Source: Himmelstoss and others (2010))
    Range of values
    Minimum:19
    Maximum:1244
    startlon
    Longitude in GCS NAD 83 of the starting point of each transect. Negative values indicate western hemisphere. (Source: Himmelstoss and others (2010))
    Range of values
    Minimum:-75.4002
    Maximum:-75.0926
    Units:decimal degrees
    startlat
    Latitude in GCS NAD 83 of the starting point of each transect. (Source: Himmelstoss and others (2010))
    Range of values
    Minimum:37.8516
    Maximum:38.3230
    Units:decimal degrees
    WidthFull
    The full width of the barrier island in meters. 'WidthFull' is the horizontal distance along transect from the oceanside MHW shorleine to the back-barrier shoreline including intervening water bodies such as back-barrier creeks. (Source: U.S. Geological Survey)
    Range of values
    Minimum:109.6
    Maximum:3637.700
    Units:meters
    WidthLand
    Width of the barrier island cross-section in meters from the oceanside MHW shorleine to the first occurance of a back-barrier shoreline. Measurement only considers width of land and not intervening water bodies such as back barrier creeks. NoData (-99999) occurs where the transect does not intersect land or the transect ends before intersecting a back-barrier shoreline. (Source: U.S. Geological Survey)
    Range of values
    Minimum:109.6
    Maximum:3440.600
    Units:meters
    LRR
    Value calculated by the Digital Shoreline Analysis System (DSAS) for the original transects (NASC transects) and appended to subsequent transect and transect point data. LRR is the linear regression rate-of-change from 1845 to 2000. It was calculated by fitting a least-squares regression line to all shoreline points for a particular transect. See Himmelstoss and others, (2010) for additional explanation of these statistics. NoData value of -99999 indicates an NASC transect is not present or does not have an LRR value. (Source: Himmelstoss and others (2010))
    Range of values
    Minimum:-6.24
    Maximum:21.49
    Units:meters/year
    beach_h
    Beach height: the vertical distance from MLLW to the dune toe. NoData (-99999) indicates values not available for a transect. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.6
    Maximum:2.7
    Units:meters
    beach_w
    Beach width: the horizontal distance from MLLW to the dune toe. NoData (-99999) indicates values not available for a transect. (Source: U.S. Geological Survey)
    ValueDefinition
    -99999No data or missing value
    Range of values
    Minimum:24.1
    Maximum:570.6
    Units:meters
    sh_slope
    Beach slope calculated between dune toe and the MHW shoreline. NoData value of -99999 occurs where a shoreline point could not be located within 25 m of the transect or the nearest point did not have a beach slope calculated. (Source: Doran and others (2017))
    ValueDefinition
    -99999No data or missing value
    Range of values
    Minimum:-0.015
    Maximum:-0.007
    Units:percent
    crest_dh_z
    Original elevation of the nearest dune crest point within 10 meters of the transect, referenced to NAVD88. NoData (-99999) indicates a dune crest could not be identified within 10 m of the transect or the nearest point did not have an elevation value. (Source: Doran and others (2017))
    ValueDefinition
    -99999No data or missing value
    Range of values
    Minimum:1.3
    Maximum:7.1
    Units:meters
    max_z
    Maximum elevation along transect, referenced to NAVD88. (Source: U.S. Geological Survey)
    Range of values
    Minimum:1.3
    Maximum:15.1
    Units:meters
    Human_mod
    The presence of human modifications to Assateague Island since 1970s. All possible values are defined here although some may not be present in this dataset. (Source: U.S. Geological Survey)
    ValueDefinition
    0No or minimal modifications present.
    1Construction present. The presence of activities to construct berms, dunes, parking lots or NPS facilities noted from aerial photographs (see 2008 source data) or GIS layers (see Morton and others (2007) and source data).
    2Occasional modification. Indicates the presence of occasional sand placement along Assateague Island.
    3Construction and occasional modofication. Indicates the presence of 2 and 3.
    4Ongoing restoration. Indicates regular sand placement (at least yearly).
    5Ongoing restoration plus construction. Indicates the presence of 4 and 5.
    dist2OCI
    Alongshore distance to Ocean City Inlet from the start of each transect. (Source: U.S. Geological Survey)
    Range of values
    Minimum:24.9
    Maximum:64164.2
    Units:meters
    dist2inlet
    Alongshore distance to nearest inlet. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:32064.8
    Units:meters
    ptZ
    Elevation referenced to NAVD88. Derived from the corresponding pixel in the 5-m DEM (2008 DEM) (Source: U.S. Geological Survey)
    Range of values
    Minimum:-1.0
    Maximum:15.0
    Units:meters
    ptSlp
    Mean slope of the corresponding 5-m pixel in the slope surface, which is derived from the 5-m DEM (2008 DEM). (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.008
    Maximum:50.117
    Units:percent
    VegRech
    Surficial groundwater recharge coefficients used to indicate vegetation and substrate types. (Source: Masterson and others (2013))
    ValueDefinition
    111indicates a coefficient of 0 for wetland.
    222indicates a coefficient of 0.00111 for shrubland or forest.
    333indicates a coefficient of 0.00167 for sand.
    444indicates a coefficient of 0.00052 for unkown substrate.
    HabNPS
    Vegetation type: dominant classification of substrate within approximately 5 m. Some values listed here may not be present these data; the list defines all values possible. NoData value of -99999 indicates that substrate type data not available (see larger work). (Source: Assateague Island National Seashore (2008).)
    ValueDefinition
    11Water: Any location that is always submerged (e.g., locations several meters into the ocean, bay, or inland water body), or was submerged at the time the map region was surveyed.
    22Sparse vegetation: indicates no vegetation or herbaceous vegetation (grasses) up to 20% cover (sparse).
    33Herbaceous vegetation: indicates herbaceous vegetative (grasses) cover between 20-90% coverage.
    44Dense herbaceous: indicates herbaceous vegetative (grasses) cover > 90%.
    55Forest or shrubland: indicates the presence of shrubs or forest vegetation.
    -99999Missing value.
    dhz_mhw
    Elevation of the nearest dune crest point to the transect, referenced to MHW. NoData (-99999) indicates a dune crest could not be identified within 10 m of the transect or the nearest point did not have an elevation value. (Source: U.S. Geological Survey)
    ValueDefinition
    -99999No data or missing value.
    Range of values
    Minimum:0.96
    Maximum:6.76
    Units:meters
    max_z_mhw
    Maximum elevation along transect, referenced to MHW. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.96
    Maximum:14.76
    Units:meters
    mean_z_mhw
    Mean elevation along transect, referenced to MHW. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.03
    Maximum:1.99
    Units:meters
    DHZnew
    Updated elevation of the nearest dune crest point within 25 meters of the transect, referenced to MHW. NoData (-99999) indicates a dune crest could not be identified within 25 m of the transect or the nearest point did not have an elevation value. (Source: U.S. Geological Survey)
    ValueDefinition
    -99999No data or missing value.
    Range of values
    Minimum:0.67
    Maximum:6.79
    Units:meters
    distDHnew
    Horizontal distance along transect from the MHW shoreline to the dune crest. NoData (-99999) occurs where a dune crest or shoreline position are not located along the transect. (Source: U.S. Geological Survey)
    ValueDefinition
    -99999No data or missing value.
    Range of values
    Minimum:20.1
    Maximum:546.53
    Units:meters
    uBW
    Upper beach width. The horizontal distance from MHW shoreline to the dune toe. NoData (-99999) occurs where beach width cannot be calculated because input values are missing or the calculation criteria are not met. (Source: U.S. Geological Survey)
    ValueDefinition
    -99999No data or missing value.
    Range of values
    Minimum:14.02
    Maximum:546.53
    Units:meters
    uBH
    Upper beach height. The vertical distance from MHW to the dune toe. NoData (-99999) occurs where beach height cannot be calculated because input values are missing or the calculation criteria are not met. (Source: U.S. Geological Survey)
    ValueDefinition
    -99999No data or missing value.
    Range of values
    Minimum:0.64
    Maximum:4.69
    Units:meters
    Human_modV2
    The presence of human modifications to Assateague Island since 1970s-updated for consistency with definitions in Sturdivant and others (2019). All possible values are defined here although some may not be present in this dataset. (Source: U.S. Geological Survey)
    ValueDefinition
    0Indicates the presence of no development (111), no nourishment (111), and no construction (111)-parentheses reference coding in fields from Sturdivant and others (2019).
    1Indicates the presence of light development (222), no nourishment (111), and no construction (111)-parentheses reference coding in fields from Sturdivant and others (2019).
    2Indicates the presence of moderate development (333), no nourishment (111), and no construction (111)-parentheses reference coding in fields from Sturdivant and others (2019).
    3Indicates the presence of no development (111) and either nourishment or construction (>111)-parentheses reference coding in fields from Sturdivant and others (2019).
    4Indicates the presence of light development (222) and either nourishment or construction (>111)-parentheses reference coding in fields from Sturdivant and others (2019).
    5Indicates the presence of moderate development (333) and either nourishment or construction (>111)-parentheses reference coding in fields from Sturdivant and others (2019).
    6Indicates the presence of no development (111), frequent nourishment (333), and no construction (111)-parentheses reference coding in fields from Sturdivant and others (2019).
    7Indicates the presence of light development (222), frequent nourishment (333), and no construction (111)-parentheses reference coding in fields from Sturdivant and others (2019).
    8Indicates the presence of moderate development (333), frequent nourishment (333)-parentheses reference coding in fields from Sturdivant and others (2019).
    ptZmhw
    Elevation referenced to MHW. Derived from attribute ptZ (ptZmhw = ptZ - MHW offset). (Source: U.S. Geological Survey)
    Range of values
    Minimum:-1.34
    Maximum:14.66
    Units:meters
    d_trans07
    Minimum distance to plant from the previous year (2007). (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.39
    Maximum:19706.9
    Units:meters
    nd30
    Number of plants within 30 m from the previous year (2007). (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:288
    Units:count
    plant_present
    Numerical value indicating if at least one seabeach amaranth plant was located within 30 m of a transect for the dataset year (2008) (Source: U.S. Geological Survey)
    ValueDefinition
    0Indicates that no plants were observed within 30 m of the transect.
    1Indicates that at least one plant was observed within 30 m of the transect.
    Entity_and_Attribute_Overview:
    This section describes the tabular data (. csv file) 'asis2008_pts.csv'. All calculations for length are in meter units and were based on the UTM zone 18N NAD83 projection. These metadata list all possible values for enumerated domains (e.g. Human_mod, HabNPS, VegRech, Human_modV2); however, some of the values described may not be present in this dataset. NoData is indicated with the value -99999. Please review the process steps for detailed information on each attribute description.
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey - ScienceBase

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Benjamin T. Gutierrez
    • Aaron Turecek
    • Erika E. Lentz
    • E. Robert Thieler
    • Nathaniel G. Plant
    • Rachel E. Henderson
    • Travis K. Sterne
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Benjamin T. Gutierrez
    U.S. Geological Survey
    384 Woods Hole Road
    Woods Hole, MA
    USA

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

Why was the data set created?

These data provide samples of barrier island characteristics for use in Bayesian networks to model geomorphology and habitat conditions for barrier island dependent species such as piping plover (Charadrius melodus) and seabeach amaranth (Amaranthus pumilus). Transects spaced every 50 m alongshore from the National Assessment of Shoreline Change (Himmelstoss and others, 2010) were extended to cover the entire barrier island. Each transect was resampled at a 5-meter spacing to sample barrier island characteristics. Attributes include both values extracted for the entire transect and values extracted at each 5-meter point.

How was the data set created?

  1. From what previous works were the data drawn?
    NASC transects (source 1 of 10)
    Himmelstoss, Emily A., Kratzmann, Meredith G., Hapke, Cheryl J., Thieler, E. Robert, and List, Jeffrey, 2010, National Assessment of Shoreline Change: A GIS Compilation of Vector Shorelines and Associated Shoreline Change Data for the New England and Mid-Atlantic Coasts: Open-File Report 2010-1119, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Shore-normal transects with long-term (1845 - 2000) shoreline change rates from the National Assessment of Shoreline Change (NASC) (DelmarvaN_LT.shp). The data are distributed as an Esri polyline shapefile referenced to World Geodetic System 1984 (WGS84), downloaded in 2012. Data last accessed 4/27/2022.
    Type_of_Source_Media: digital data
    Source_Contribution:
    Shore-normal transects were converted to a point dataset with points spaced at 5 meter increments along each transect. Barrier island geomorphology metrics from a wide range of sources were appended to transects and transect points. See browse graphic for an illustration of transects, points, and geomorphology assessed along the cross shore transect.
    Shoreline morphology (source 2 of 10)
    Doran, Kara S., Long, Joseph W., Stockdon, Hilary F., Birchler, Justin J., Hardy, Matthew W., Morgan, Karen L.M., and Brenner, Owen, 20170609, 2008 Assateague Island USGS EAARL Lidar-Derived Dune Crest, Toe and Shoreline: data release doi:10.5066/F7GF0S0Z, U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

    Other_Citation_Details:
    This dataset (08LTS05_morphology.zip) defines the elevation and position of the seaward-most dune crest and toe and the mean high water shoreline derived from the 2008 Assateague Island (Virginia and Maryland) USGS Experimental Advanced Airborne Research Lidar (EAARL) lidar survey (FAN: 08LTS05). Data were downloaded in 2012 and in updated form in 2019.
    Type_of_Source_Media: tabular digital data
    Source_Contribution:
    Barrier island metrics from this dataset (08LTS05_morphology.zip) were extracted to the ASIS transect and transect points datasets.
    2008 Ortho (source 3 of 10)
    Axis GeoSpatial, LLC, 2008, 2008 Assateague Island National Seashore Aerial Photography Mosaic: Assateague Island National Seashore, Berlin, Maryland.

    Online Links:

    Other_Citation_Details:
    Visual imagery used for confirming remote sensing data sources such as vegetation and substrate layers. Source data were distributed at 6" ground resolution. The resulting mosaic was reprojected to UTM Zone 18N NAD83, and compressed to 400Mb SID file, using a 200:1 compression rate. Downloaded from nrdata.nps.gov/ASIS/ASISdata/asis_color_2008 (no longer operational) on 6/09/2010. Current website (below) accessed 4/27/2022.
    Type_of_Source_Media: digital data
    Source_Contribution:
    Imagery was used to confirm remote sensing data sources such as vegetation and substrate layers before appending to the ASIS transect point dataset.
    2008 DEM (source 4 of 10)
    U.S. Geological Survey Coastal and Marine Geology Program, Bonisteel, Jamie M., Nayegandhi, Amar, Brock, John C., Wright, C. Wayne, Stevens, Sara, Yates, Xan, and Klipp, Emily S., 2009, EAARL Coastal Topography--Assateague Island National Seashore, 2008: Bare Earth elevation: U.S. Geological Survey Coastal and Marine Geology Program, St. Petersburg, FL.

    Online Links:

    Other_Citation_Details:
    Elevation grid. Source data were downloaded from https://pubs.usgs.gov/ds/447/ in horizontal datum NAD83 UTM Zone 18N, vertical datum NAVD88.
    Type_of_Source_Media: Online digital data
    Source_Contribution:
    The 2008 DEM was used to provide elevation values, which were extracted to ASIS transect point data. Original data downloaded was in UTM Zone 18N NAD83.
    ASIS Boundary (source 5 of 10)
    Assateague Island National Seashore, and Specialist, GIS, 2006, Assateague Island: 2003-2010 Boundary: Assateague Island National Seashore, Berlin, Maryland.

    Online Links:

    Other_Citation_Details:
    This shapefile (Assateague_Island_2003_2010.shp) portrays the Assateague Island shoreline as well as the shorelines of many smaller islands that surround it on the bay coast. This dataset was derived from digitizing October 2003 aerial photography and shoreline GPS surveys collected in 2010.
    Type_of_Source_Media: digital data
    Source_Contribution:
    The Assateague Island shoreline (ASIS Boundary) was used to help define the back-barrier portion of the island.
    Human modification polygons (source 6 of 10)
    Morton, Robert A., Bracone, Jeremy E., and Cooke, Brian, 2007, Geomorphology and depositional sub-environments of Assateague Island MD/VA.: Open-File Report 2007-1388, U.S. Geological Survey Florida Integrated Sciences Center, St. Petersburg, FL.

    Online Links:

    Other_Citation_Details:
    Polygons of geomorphology and depositional environments on Assateague Island National Seashore. The data are distributed as Esri polygon shapefiles referenced to UTM Zone 18N NAD83. They were downloaded in 2010.
    Type_of_Source_Media: digital data
    Source_Contribution:
    Polygons of geomorphology and depositional environments were used to append human modification characteristics to the ASIS transect point dataset.
    ASIS sediment (source 7 of 10)
    Assateague Island National Seashore, and Specialist, GIS, 201003, Sediment By-passing Events Related to the Assateague Island National Seashore North End Restoration Project, 2004-2010: Assateague Island National Seashore, Berlin, Maryland.

    Online Links:

    Other_Citation_Details:
    This dataset contains point locations where sediment by-passing events took place for the Assateague Island National Seashore North End Restoration Project. These events were undertaken by the United States Army Corps of Engineer (USACE) dredge ship Currituck between the years of 2004 and 2010. Events correspond to either dredging, or sediment deposition (placements).
    Type_of_Source_Media: digital data
    Source_Contribution:
    This data was used to define locations of sediment deposition as relates to human modification. This data was added to the transect data, see process step 7.
    ASIS Habitat (source 8 of 10)
    Assateague Island National Seashore, and Specialist, GIS, 20041104, Assateague Island National Seashore North End Piping Plover habitat collected in 2008.: Assateague Island National Seashore, Berlin, Maryland.

    Online Links:

    Other_Citation_Details:
    This file contains polygons representing the ocean and bay shoreline, herbaceous, sparse, and woody vegetation, ponds, and mudflats on the northern 9.5 kilometers of Assateague Island. Data retrieved from asis-nps.opendata.arcgis.com are projected to WGS 1984 Web Mercator Auxiliary Sphere. Data received directly from staff at the National Park Service (NPS) Assateague Island National Seashore remain in NAD 83 2011 UTM Zone 18 N projection. Received from Assateague Island National Seashore GIS Specialist 5/2012.
    Type_of_Source_Media: digital data
    Source_Contribution:
    This polygon data, describing vegetation zones on the northern 9.5 km of Assateague Island, was used to extract information about the vegetation type to the transect point dataset.
    ASIS recharge (source 9 of 10)
    Masterson, John P., Fienen, Michael N., Gesch, Dean B., and Carlson, Carl S., 2013, Development of a Numerical Model to Simulate Groundwater Flow in the Shallow Aquifer System of Assateague Island, Maryland and Virginia: Open-File Report 2013-1111, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Georeferenced data layer consisting of ground water recharge coefficients defined based on substrate and vegetation type data. Obtained from the authors per-request. Shapefile georeferenced using UTM Zone 18N NAD83.
    Type_of_Source_Media: digital data
    Source_Contribution:
    Polygon of data related to substrate and vegetation type was used to extract information about the vegetation type to the transect point data.
    Seabeach Amaranth Field Data (source 10 of 10)
    Chase, Jonathan B., Hulslander, Bill, Strum, Mark, Lea, Chris, Gutierrez, Benjamin T., Henderson, Rachel E., and Sterne, Travis K., 2023, Assateague Island Seabeach Amaranth Survey Data — 2001 to 2018: data release DOI:10.5066/P9IZMQ1B, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Chase, J.B., Hulslander , B., Strum, M., Lea, C., Gutierrez, B.T., Henderson, R.E., and Sterne, T.K., 2023, Assateague Island seabeach amaranth survey data — 2001 to 2018: U.S. Geological Survey data release, https://doi.org/10.5066/P9IZMQ1B These data provide samples of barrier island characteristics for use in Bayesian networks to model geomorphology and shorebird nesting habitat condition and change in 2008 at Assateague Island National Seashore (Virginia and Maryland).
    Type_of_Source_Media: tabular and vector digital data
    Source_Contribution:
    From 2001 - 2018 NPS collected field data on the presence of Seabeach Amaranth. This data was used to inform ASIS transect point data with date specific (2007-2008) values of amaranth populations.
  2. How were the data generated, processed, and modified?
    Date: 2012 (process 1 of 15)
    Process overview: These data provide barrier island characteristics along Assateague Island National Seashore for points distributed at 5 m intervals along cross-shore transects. The point dataset includes values extracted for the entire transect ('ASIS_transects.shp') and values extracted at each individual point (final file, 'asis_2008pts.csv'). The following process steps describe the appending of data to transects, the conversion of transects to points, and the appending of additional data to the point dataset. All processing was completed by either Benjamin T. Gutierrez or Aaron Turecek. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Benjamin T. Gutierrez
    Geologist
    384 Woods Hole Road
    Woods Hole, MA
    US

    508-548-8700 x2289 (voice)
    508-457-2310 (FAX)
    bgutierrez@usgs.gov
    Date: 2012 (process 2 of 15)
    Step 1) Extension of existing transect data (NASC transects) to cover the full width of Assateague Island, resulting in a new transect shapefile (ASIS_transects.shp). All processing was done in ArcMap ver. 9.3.
    'NASC transects' (Himmelstoss and others 2010) were extended 2000 m inland to cover the width of the barrier, starting at the startlon startlat coordinates (or the landward end vertex of each transect), and using the attribute “Azimuth” with the “Bearing Distance To Line” function ( ArcToolbox >> Data Management Tools >> Features >> Bearing Distance to Line). The field value ‘TRANSORDER’ is retained from the source data to serve as a transect identifier and to provide a reference to the source data. The extension of the transects to span the full island width results in some overlapping transects. In addition, the data was projected (ArcToolbox >> Data Management Tools >> Projections and Transformations >> Project) from WGS84 to UTM Zone 18N NAD83. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Aaron M. Turecek
    Geographer
    384 Woods Hole Road
    Woods Hole, MA
    US

    508-548-8700 x2230 (voice)
    508-457-2310 (FAX)
    aturecek@usgs.gov
    Data sources used in this process:
    • NASC transects
    Data sources produced in this process:
    • ASIS_transects.shp
    Date: 2012 (process 3 of 15)
    Step 2) Extraction of six shoreline morphology elements from existing tabular (Shoreline morphology) and raster (2008 DEM) data to interim datasets which will be used in subsequent process steps. All processing was completed in MATLAB ver. 2009. MHW shoreline positions, beach slope ('sh_slope'), foredune crest positions and elevation ('crest_dh_z'), dune toe positions and elevations were extracted from Doran and others (2017; dataset 08LTS05 dataset). Beach width ('beach_w') and beach height ('beach_h') are calculated based on the difference in position between two points: the position of the estimated mean lower-low water (MLLW) shoreline along a transect (ASIS_transects.shp); and the dune toe position (Doran and others, 2017). The MLLW shoreline was estimated by using the beach slope ('sh_slope') to extrapolate the MLLW elevation intersect (-0.76 m NAVD88 at the NOAA Tide Gauge # 8570283, Ocean City, Maryland, Tidal datum analysis period: 08/01/2002 - 07/31/2008). To do this, the horizontal distance between the MHW shoreline intersect and the MLLW intersect were estimated by dividing the vertical offset between the two (0.34 m and -0.76 m) by the tangent of the beach slope. The resulting horizontal distance value, the transect azimuth (using the ‘distance.m’ function), and the MHW shoreline intersect was used in the ‘reckon.m’ function to extrapolate the MLLW shoreline position and determine the MLLW shoreline coordinates. The beach width ('beach_w') was then calculated as the euclidean distance between the MHW shoreline coordinates and the MLLW coordinates in the ‘distance.m’ function in MATLAB. In some cases, the dune toe is not present in the dataset. Where these values were missing, subject matter experts on the research team determined that the foredune dune crest position should be inserted as a substitute if available and if its elevation is less than or equal to 2.0 m (NAVD88). If no dune features are encountered within 10 m of a transect, foredune crest height, dune toe elevation, beach height and beach width are given a NoData value of -99999. The maximum elevation along a transect ('max_z') was added using MATLAB. Elevation referenced to NAVD88. Derived from the corresponding pixel in the 5-m DEM. The maximum elevation for each transect was calculated in MATLAB and appended to the cells corresponding to each transect. Data sources used in this process:
    • Shoreline morphology
    • ASIS_tansects.shp
    • 2008 DEM
    Data sources produced in this process:
    • beach_w
    • beach_h
    • sh_slope
    • crest_dh_z
    • MHW shoreline positions
    • max_z
    Date: 2012 (process 4 of 15)
    Step 3) Append morphology from Step 2 to entire cross shore transects ('ASIS_transects.shp') resulting in a new transect output: 'ASIS_trans2_morphology.shp'. This processing was completed in ArcMap ver. 9.3. 'ASIS_transects.shp' is populated with the linear regression shoreline change rate values ‘LRR’ from the original 'NASC transects', and morphology from the previous step: dune crest height (‘crest_dh_z’), beach slope (‘sh_slope’), beach width (‘beach_w’) and beach height (‘beach_h’). Values are populated for each transect through a series of manual steps using ArcToolbox (ver. 9.3). The “Spatial Join” function (ArcToolbox >> Analysis Tools >> Spatial Join) was used to match these variables to each transect. If any of the variables did not occur within 10 m of the transect, null values were returned for that variable and later replaced with NoData values used for this dataset (-99999). Data sources used in this process:
    • beach_w
    • beach_h
    • sh_slope
    • crest_dh_z
    • ASIS_transects.shp
    Data sources produced in this process:
    • ASIS_trans2_morphology.shp
    Date: 2012 (process 5 of 15)
    Step 4) Using an existing barrier island boundary ('ASIS Boundary') and the 'MHW shoreline positions' data, two new shoreline files were created: an ocean facing shoreline ('MHW shoreline feature'), and a polygon that encompasses the full shoreline extent ('full shoreline polygon'). All processing was completed in ArcMap ver. 9.3.
    Some terminology before processing: The MHW shoreline is the oceanside shoreline defined by the MHW contour line adjacent to the open ocean, and bounded (north and south) by either tidal inlet or the study area extent. In some cases, we may use MHW shoreline interchangeably with oceanside shoreline. The back-barrier shoreline refers to the boundary between land and water on the inland side of the island. The ‘full shoreline polygon’ outlines the boundary between land and water for the entire study area from the oceanside shoreline (MHW) to the back-barrier shoreline.
    The back-barrier shoreline was obtained from a National Park Service data layer (‘ASIS Boundary’), that contained a high resolution back-barrier shoreline (digitized from 2003 orthophotos). The back-barrier shoreline was manually clipped from this polygon at the inlet locations. The ‘MHW shoreline points’ (which occur every 10 m along the ocean facing shore) were converted to a polyline using the “Points To Line” function (ArcToolbox >> Data Management Tools >> Features >> Points to Line). The two shorelines, MHW and back-barrier, were merged to form a single polygon (ArcToolbox >> Data Management Tools >> General >> Merge). Gaps occurring at Ocean City Inlet to the north and Chincoteague Inlet to the south, were connected by manually drawing the shoreline using 2008 digital orthophotos as a guide (Source data: 2008 Ortho). The resulting polygon was saved as the ‘full shoreline polygon’ Data sources used in this process:
    • ASIS Boundary
    • MHW shoreline positions
    • 2008 Ortho
    Data sources produced in this process:
    • full shoreline polygon
    • MHW shoreline feature
    Date: 2012 (process 6 of 15)
    Step 5) Calculated the distance from each transect to Ocean City Inlet (‘dist2OCI’), then determined the distance from each transect to the closest inlet (‘Dist2Inlet’). Assateague Island is bounded by Ocean City Inlet to the north, and Chincoteague Inlet to the south. Values appended to fields in new transect shapefile ('ASIS_trans3_inlets.shp').
    The distance to Ocean City ('dist2OCI’) is computed in ArcMap ver. 9.3 as the alongshore distance of each transect location from Ocean City Inlet. The calculated distances include changes in the path of the oceanside shoreline rather than just a straight-line distance between each transect and the inlet and reflects sediment transport pathways. The MHW shoreline feature and the ‘Create Routes’ tool (ArcToolbox >> Linear Referencing Tools >> Create Routes) were used to calculate distance values. Locate Features Along Routes (ArcToolbox >> Linear Referencing Tools >> Create Routes >> Locate Features Along Routes) was used to orient the direction of the calculation by specifying starting coordinates at Ocean City Inlet. ‘Join Field’ and ‘Calculate Field’ in the Data Management Tools were used to merge the routes with ‘TRANSORDER’ and calculate distances along the routes respectively.
    Distance to nearest inlet ('dist2inlet') was calculated in Matlab using the ‘dist2OCI’ field from the previous step by identifying the mid-point distance along Assateague Island and subtracting that value from values greater than the mid-point value. Data sources used in this process:
    • MHW shoreline feature
    • ASIS_trans2_morphology.shp
    Data sources produced in this process:
    • ASIS_trans3_inlets.shp
    Date: 2012 (process 7 of 15)
    Step 6) Calculated island width from the ‘full shoreline polygon’ (created in Process Step 4), appended fields ('WidthLand', and 'WidthFull') and clipped transects ('ASIS_trans3_inlets') to shoreline extent, resulting in a new file 'ASIS_trans4_width.shp'. All processing was completed in ArcMap ver. 9.3. Barrier island width ('WidthLand') is calculated as the width between the back-barrier and oceanside shorelines along the transect using the 'full shoreline polygon'. 'WidthLand' does not include where transects cross waterways that intersect them. We also measure the shore-to-shore extent of the island ('WidthFull'), which includes space occupied by waterways. These are calculated as follows: (1) Clip the transects to the 'full shoreline polygon' (ArcToolbox >> Analysis Tools >> Clip); (2) for 'WidthLand', get the length of the multipart line segment from "SHAPE_Length" feature class attribute using ‘Calculate Field’ (ArcToolbox >> Data Management Tools >> Fields >> Calculate Field), which will include only the remaining portions of the transect; (3) for 'WidthFull', use ‘FeatureVerticesToPoints’ (ArcToolbox >> Data Management Tools >> Features >> Feature Vertices to Points) to obtain the first and last intersects with the island boundary polygon. Following this ‘PointsToLine’ (ArcToolbox >> Data Management Tools >> Features >> Points to Line) was used to construct a line segment between these vertices. ‘Calculate Field’ (ArcToolbox >> Data Management Tools >> Fields >> Calculate Field) was then used calculate the length of each transect using these line segments. Island width field values were appended to a new shapefile, 'ASIS_trans4_width.shp'. Data sources used in this process:
    • ASIS_trans3_inlets.shp
    • full shoreline polygon
    Data sources produced in this process:
    • ASIS_trans4_width.shp
    Date: 2012 (process 8 of 15)
    Step 7) Append metric for human modification to 'ASIS_trans4_width.shp' from previous step, with a new output created 'ASIS_trans5_human.shp'. Processing was completed in MATLAB ver. 2009.
    Human modification polygons were manually assigned coded values(in MATLAB ver. 2009) for human modifications and management activities undertaken on Assateague Island, by comparing the transect positions to ancillary datasets (viewed in ArcGIS 9.3). These datasets included the inventory of geomorphic environments (Morton and others, 2008; Krantz and others, 2009), available aerial imagery (2008 Orthos), and unpublished NPS management reports for Assateague Island (ASIS sediment). The field value ‘Human_mod’ was appended to existing data in 'ASIS_trans4_width.shp'. Each transect was assigned a value based on the intersection with the source data referenced above and these data. Six values were defined for the field: no modification or management activity (value = 1); constructed features present (value = 2), occasional modification (value = 3), construction plus occasional restoration (value = 4), ongoing restoration (value = 5), and ongoing restoration plus construction (value = 6). Data sources used in this process:
    • Human modification polygons
    • ASIS sediment
    • 2008 Orthos
    • ASIS_trans4_width.shp
    Data sources produced in this process:
    • ASIS_trans5_human.shp
    Date: 2012 (process 9 of 15)
    Step 8) Modified ASIS transects data from all previous steps ('ASIS_trans5_human') was converted to a point dataset within ArcMap ver. 9.3. All existing transect attributes from previous steps are preserved and carried over to the new point shapefile ('ASIS_trans_points.shp').
    This dataset represents 5 m sampling of the land along each shore-normal transect. The point file is created from the modified transect file ‘ASIS_trans5_human.shp’ as follows: 1) Convert transects to individual segments using ‘Multipart to Single Part’ (ArcToolbox >> Data Management Tools >> Features >> Multipart to Singlepart), 2) split transects into segments every 5 m using XTools Pro function ‘Split Polylines’, 3) convert segments to center points using ‘Feature to Point’ (ArcToolbox >> Data Management Tools >> Features >> Feature to Point), 4) add x and y coordinates (seg_x, seg_y; UTM zone 18N NAD 83) for each center point (ArcToolbox >> Data Management Tools >> Features >> Add XY Coordinates). Data sources used in this process:
    • full shoreline polygon
    • ASIS_trans5_human.shp
    Data sources produced in this process:
    • ASIS_trans_points.shp
    Date: 2012 (process 10 of 15)
    Step 9) The following fields were calculated within ArcGIS (ver. 9.3): 'pID', 'dist2MHW', dist2MHWBay, ptZ, ptSlp, VegRech, HabNPS. Results were appended to the transect point data from the previous step (ASIS_trans_points.shp) and were saved as a new point file ‘ASIS_trans_pts2.shp’. Point identifier: We populate the point shapefile from the previous step (‘ASIS_trans_points.shp’) with a numerical point identifier ('pID') Values were assigned after sorting by order along oceanside shoreline (‘TRANSORDER’) then by distance from the oceanside shoreline (‘dist2MHW’). Distance fields: ‘dist2MHW’ and ‘dist2MHWBay’ measure the distance of the transect point from the shoreline adjacent to the open ocean and the shoreline adjacent to the back-barrier waterbody respectively. 'dist2MHW’ is calculated using ‘Calculate Field’ (ArcToolbox >> Data Management Tools >> Fields >> Calculate Field) to calculate a distance for each point to the ‘MHW shoreline feature’. ‘dist2MHWBay’ is calculated by subtracting the ‘dist2MHW’ value from the field 'WidthLand'. A NoData value for ‘WidthLand’ prevents the calculation of dist2MHWBay. Elevation and slope fields: 'ptZ' and 'ptSlp' are the mean elevation (NAVD88) and mean slope of elevations within the 5 m cells centered at each seg_x and seg_y coordinate. We used the 5 m DEM (2008 DEM) to generate an elevation and a slope surface (ArcToolbox >> 3D Analyst Tools >> Raster Surface >> Slope). The elevation and slope values are assigned to the points using the Extract Multi Values to Points tool (ArcToolbox >> Spatial Analyst Tools >> Extraction >> Extract Multi Values to Points). VegRech: This field was derived from Masterson and others (2013; ASIS recharge) which was assembled using a 1993 vegetation dataset for the Maryland portion of Assateague Island. The ‘Spatial Join’ function in the Analysis Tools of ArcToolbox was used to sample the ‘VegRech’ layer to each coordinate (seg_x, seg_y). The layer consisted of four landcover categories: 111 = wetland, 222 = shrubland or forest, 333 = sandy, and 444 = unknown. HabNPS: This field is based on piping plover habitat maps (ASIS Habitat) that approximate vegetation zones on the northern 9.5 km of Assateague Island. The values of this dataset consist of a map consisting of five vegetation cover categories: 11 = water, 22 = sparse, 33 = herbaceous, 44 = dense herbaceous, and 55 = forest or shrubland. The Extract Multi Values to Points tool in Spatial Analyst of ArcToolbox was used to sample the ‘asis_pipl_habitat2008.tif’ layer to each coordinate (seg_x, seg_y). Data sources used in this process:
    • MHW shoreline feature
    • WidthLand
    • 2008 DEM
    • ASIS recharge
    • ASIS Habitat
    Data sources produced in this process:
    • ASIS_trans_pts2.shp
    Date: 2012 (process 11 of 15)
    Step 10) Additional metrics were calculated to adjust certain fields to MHW. The following fields (described in detail below) were added within MATLAB (ver. 2009) to the point shapefile from the previous step (‘ASIS_trans_pts2.shp’): dhz_mhw, ptZmhw, max_z_mhw, mean_Z_mhw. The resulting file was output as a .csv point dataset, ‘ASIS_trans_pts3.csv’.
    The existing attributes ‘crest_dh_z’, ‘ptZ’, and ‘max_z’ elevations were adjusted to the local MHW datum by subtracting 0.34 m. This value was developed by Weber and others (2005) and represents local/regional differences of MHW elevation from NAVD88. These new fields were labeled ‘dhz_mhw’ for the adjusted foredune crest elevation, ‘ptZmhw’ for the elevation, and ‘max_z_mhw’ for the maximum elevation along the corresponding transect.
    Mean barrier elevation (‘mean_Z_mhw’) was calculated using ‘ptZmhw’ for only those transects having less than 20 percent missing values within the 5-m points. Locations not satisfying this criterion are assigned a fill value of -99999. Data sources used in this process:
    • ASIS_trans_pts2.shp
    Data sources produced in this process:
    • ASIS_trans_pts3.csv
    Date: 2021 (process 12 of 15)
    Step 11) Additional fields were recalculated for consistency with published data from Sturdivant and others (2019). The following fields (described in detail below) were added within MATLAB (ver. 2018) to the point file from the previous step (‘ASIS_trans_pts3.csv’): 'DZnew', 'distDHnew', 'uBW', 'uBH' and 'Human_modV2'. The resulting file was output as a .csv point dataset, ‘ASIS_trans_pts4.csv’.
    In order to sample the data consistently with data from Sturdivant and others (2019), adjustments were made to several variables in the 2008 dataset and appended as additional fields using Matlab. The original data extraction sampled shoreline metrics within 10 m of a transect. Sturdivant and others (2019) conducted this sampling with a wider sampling window of 25 m on either side of a transect. Updated dune metrics and resulting beach width and height calculations were redone to ensure that data used in this study were sampled consistently with the updated methods. Consequently, foredune crest height (’dhz_mhw’) and corresponding locations were resampled by identifying the nearest foredune crest height and dune toe locations within 25 m for each transect from the Doran and others (2017) dataset. In addition, the threshold of 2 m was increased to 2.5 m to insert dune crest elevations where dune toe elevations and positions were not available.
    The new fields were labelled ‘DHZnew’ for the foredune crest elevation. Distance to foredune crest (‘distDHnew’) was again calculated as the distance from the dune toe to the MHW shoreline. Upper beach width (‘uBW’) was calculated for each transect using the dune toe and MHW locations described previously. This represents the horizontal distance from the dune to the mean high-water shoreline. Beach height (uBH) was calculated as the vertical difference between the dune toe elevation and the MHW shoreline. This represents a difference from the original calculation of beach_w and beach_h, which were referenced to the MLLW shoreline. Data sources used in this process:
    • ASIS_trans_pts3.csv
    Data sources produced in this process:
    • ASIS_trans_pts4.csv
    Date: 2021 (process 13 of 15)
    Step 12) The original field ‘human_mod’ was reclassified using fields as defined by Sturdivant and others (2019), and the output saved to a new field ‘human_modV2’, and saved to a new output transect point file ‘ASIS_trans_pts4.csv’
    Human_modV2: The original Human_mod field (ASIS_trans_pts3.csv) was redefined by combining the Nourishment, Development, and Construction fields defined for Sturdivant and others (2019) into a single category consistent with the original definitions in Human_mod. These values were defined as 0 = no development (111), no nourishment (111), and no construction (111); 1 = light development (222), no nourishment (111), and no construction (111); 2 = moderate development (333), no nourishment (111), and no construction (111); 3 = no development (111) and either nourishment or construction >111; 4 = light development (222) and either nourishment or construction >111; 5 = moderate development (333) and either nourishment or construction >111; 6 = no development (111), frequent nourishment (333), and no construction (111); 7 = light development (222), frequent nourishment (333), and no construction (111); 8 = moderate development (333), frequent nourishment (333). In these definitions, nourishment refers to any activity involving the placement of sand on the beach or in the surf zone to offset long-term erosion. The results were saved to a new field ‘Human_modV2’ in the output file ‘ASIS_trans_pts5.csv’ Data sources used in this process:
    • ASIS_trans_pts4.csv
    Data sources produced in this process:
    • ASIS_trans_pts5.csv
    Date: 2021 (process 14 of 15)
    Step 13) Three additional parameters were included with these data to capture the presence of seabeach amaranth: 'd_trans07', 'nd30', and 'plant_present'. Field collected seabeach amaranth (Amaranthus pumilus) data from ‘Seabeach Amaranth Field Data’ was appended to the original 'ASIS_transects' data using MATLAB (ver. 2009). Results were appended to the transect points file from previous steps 'ASIS_trans_pts5.csv', and exported to the final output file ‘asis2008_pts.csv’
    ‘d_trans07’ is the absolute value of the minimum distance to the nearest plant from the previous year from a transect. This was processed in Matlab by calculating the Euclidean distance of each plant location from the previous year to the transect. For these data from 2008, plant locations from 2007 were used. The absolute value of the minimum Euclidean distance from the nearest plant was then calculated.
    ‘nd30’ is the number of plants occurring within 30 m of a transect. This was computed in Matlab by calculating the Euclidean distance of each plant location from the previous year to the transect. For these data from 2008, plant locations from 2007 were used. Transects occurring within 30 m of a plant location were then recorded. Repeating transect values were then identified and counted resulting in the number of plants occurring within 30 m of a transect.
    ‘plant_present’ is a presence-absence field that specifies whether there was a seabeach amaranth plant located withing 30 m of a transect. ‘plant_present’ was calculated in Matlab by calculating the Euclidean distance of each plant location to the transect. Transects matched with plants were then recorded and a list of unique transect values was retained. Corresponding transects were then coded with a ‘1’. The remaining transects, where no plants were located within 30 m, where then coded with a ‘0’. Data from transects appended to transect points using a spatial join. Data sources used in this process:
    • Seabeach Amaranth Field Data
    • ASIS_transects
    • ASIS_trans_pts5.csv
    Data sources produced in this process:
    • asis2008_pts.csv
    Date: 10-May-2023 (process 15 of 15)
    An author name in a source citation was misspelled and fixed. (20230510) Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Rd.
    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?
    Gutierrez, Benjamin T., and Lentz, Erika E., 2023, Developing a habitat model to support management of threatened seabeach amaranth (Amaranthus pumilus) at Assateague Island National Seashore, Maryland and Virginia: Scientific Investigations Report 2023–5034, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Scientific Investigations Report associated with data releases DOI:10.5066/P9IZMQ1B and DOI:10.5066/P9GKXN3H. Suggested citation: Gutierrez, B.T., and Lentz, E.E., 2023, Developing a habitat model to support management of threatened seabeach amaranth (Amaranthus pumilus) at Assateague Island National Seashore, Maryland and Virginia: U.S. Geological Survey Scientific Investigations Report 2023–5034, https://doi.org/10.3133/sir20235034.
    Gutierrez, Benjamin T., Plant, Nathaniel G., Thieler, E. Robert, and Turecek, Aaron, 2015, Using a Bayesian network to predict barrier island geomorphic characteristics: Journal of Geophysical Research: Earth Surface 120, American Geophysical Union, Washington D.C..

    Online Links:

    Gieder, Katherina D., Karpanty, Sarah M., Fraser, James D., Catlin, Daniel H., Gutierrez, Benjamin T., Plant, Nathaniel G., Turecek, Aaron M., and Thieler, E. Robert, 2014, A Bayesian network approach to predict nest presence of the federally-threatened piping plover (Charadrius melodus) using barrier island features: Ecological Modelling 276, Elsevier, Amsterdam Netherlands.

    Online Links:

    Weber, Kathryn M., List, Jeffrey H., and Karen L. M. Morgan, 2005, An Operational Mean High Water Datum for Determination of Shoreline Position from Topographic Lidar Data: Open-File Report 2005-1027, U.S. Geological Survey, Reston, VA.

    Online Links:

    Sturdivant, Emily J., Zeigler, Sara L., Gutierrez, Benjamin T., and Weber, Kathryn M., 20191220, points, transects, beach width: Barrier island geomorphology and shorebird habitat metrics at 50-m alongshore transects and 5-m cross-shore points: Assateague Island, MD and VA, 2014: data release DOI:10.5066/P9V7F6UX, U.S. Geological Survey, Reston, VA.

    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:
    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.
    Zeigler, Sara L., Sturdivant, Emily J., and Gutierrez, Benjamin T., 20191220, 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:

    Krantz, David E., Schupp, Courtney A., Spaur, Christopher C., Thomas, Jane E., and Wells, Darlene V., 2009, Shifting Sands Environmental and cultural change in Maryland’s Coastal Bays Chapter 12: Dynamic systems at the land-sea interface.: Book ISBN 978‒0‒9822305‒0‒3, University of Maryland Center for Environmental Science (UMCES), Cambridge, MD.

    Online Links:

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

  1. How well have the observations been checked?
    Attribute values at each point represent a 5 x 5 m square centered at the point. The values are compiled from multiple sources and generated in two phases: first data from previous studies (Gieder and others, 2014 and Gutierrez and others, 2015) were updated to be sampled consistently with later work by Sturdivant and others (2019) and Zeigler and others (2019) and second, the data were utilized to support this study (Gutierrez and Lentz, 2023). Cross-shore (transect)-averaged values, such as foredune crest height, distance to dune crest, beach width, and beach height may represent these metrics up to 10 m and 25 m on either side of the indicated data. The following methods were used to validate attribute accuracy: symbolized display point attribute values overlaid on input datasets including elevation, barrier extent, geomorphic feature (ArcMap ver. 9.3, ArcGIS Pro ver. 2.0); spot-checking of values at individual points and comparison with input datasets and topology (ArcMap ver. 9.3 and ArcGIS Pro ver. 2.0). Accuracy of the MHW shoreline position, foredune crest coordinates and elevation, dune toe coordinates and location, and consequently the beach width, height values, and distance to foredune crest values are dependent on the accuracy of the lineage data (Doran and others, 2016). Beach widths are calculated to the tenths of meters in precision and elevations are accurate to +/- 15 cm. Nonetheless, the values are only calculated every 50 m alongshore. As a result, a given cell value may represent these metrics at a point as far as 25 m removed from the cell. Refer to the process steps for details. Dune crest height, dune toe elevation, beach width, and beach height values were spot-checked while verifying the reliability of the transect values. Spot checks were performed by plotting these metrics on a cross-shore elevation profile to verify that they were within agreement. Where differing values were encountered for each of the metrics mentioned here, they were compared to lidar elevation surfaces from the source dataset and aerial photographs for investigation. If the source of the errant values couldn't be verified, fill values (-99999) were entered in the field for that point.
  2. How accurate are the geographic locations?
    Depending on the attribute, the accuracy is assumed to be between 5 and 25 m. The horizontal positional accuracy is dependent on the accuracy of the source data and error incorporated during processing. Refer to the process steps for details.
  3. How accurate are the heights or depths?
    The vertical accuracy of those attributes that incorporate vertical position is dependent on the digital elevation model and its source data (see Source Information in Process Steps) as well as the MHW datum produced by Weber and others (2005).
  4. Where are the gaps in the data? What is missing?
    Dataset completeness is dependent on the completeness of the source data. Transects are spaced along the ocean facing shoreline approximately every 50 m within the study area, with some variation on the inland side. Transects may overlap in areas where there is a change in shoreline orientation. There may be gaps in the transect spacing due to the lack of a sufficient number of historical shorelines available in the calculation of the source data (Himmelstoss and others, 2010). Points are spaced every 5 m along the transects within the full island shoreline boundary (see Process Steps). In some instances, there were gaps in the digital elevation model (2008 DEM) that was used to extract elevation values. Gap locations noted with NoData values (-99999). Two of the layers that were used (VegRech and HabNPS) only covered portions of the study area. Areas where data is absent are noted with NoData values (-99999).
  5. How consistent are the relationships among the observations, including topology?
    These datasets consist of data compiled from multiple sources and aggregated spatially. The data were reviewed using standard USGS review procedures. No checks for topological consistency in addition to those described in the Attribute Accuracy Report were performed on these data. The primary vertical datum used is NAVD88, consistent with the source datasets lidar, shoreline and dune metrics. Some fields (those with a 'mhw' suffix and explained in the Entity and Attribute section) include the elevation adjusted to the mean high water (MHW) datum calculated by Weber and others (2005) for the area. Where a given attribute value could not be calculated due to lack of input data in the lineage dataset, a NoData value of -99999 was recorded for the attribute. Where a transect does not intersect land, it corresponds to a single point with NoData values for all attributes. More detail is provided in the Entity and Attribute Information.
    Point data in this dataset (distributed as a .csv file) are first generated as point shapefiles at 5 m intervals along existing transect features. Transects (Himmelstoss and others, 2010) are identified by the field TRANSORDER, with orders the transects sequentially (from south to north) along the shoreline. Transects are spaced alongshore approximately every 50 meters within the study area. Transect extent and distribution is based on the study area rather than the shoreline, to allow transect positions to encompass the land in years with different shoreline positions. As a result, some transects may not intersect land in certain years. Curves in the generalized shoreline may cause transect spacing to vary from the standard 50 m alongshore, especially along the inland side of the study area. Transects are not always orthogonal to the section of shore they intersect and they may overlap. In such cases, the complete transect was preserved allowing overlap so that each transect could measure the full width of the barrier. Cells may not have the same value as neighboring cells directly oceanward because of the same overlap-elimination process applied to the transects.

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 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 point data as a generic comma-separated ASCII formatted data file (asis2008_pts.csv). The CSDGM FGDC metadata describing the dataset is available in XML and HTML format (asis2008_pts_metadata.xml, asis2008_pts_metadata.html). 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 a comma-seperated data file.

Who wrote the metadata?

Dates:
Last modified: 10-May-2023
Metadata author:
Rachel E. Henderson
U.S. Geological Survey
384 Woods Hole Road
Woods Hole, MA
USA

508-548-8700 (voice)
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.
Metadata standard:
Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/SB_data_release/DR_P9GKXN3H/asis2008_pts_metadata.faq.html>
Generated by mp version 2.9.51 on Fri May 12 10:09:45 2023