FIIS_Shorelines_Oct2012_Oct2017.shp: Fire Island, NY pre- and post-storm shoreline data from October 2012 to October 2017

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Frequently anticipated questions:


What does this data set describe?

Title:
FIIS_Shorelines_Oct2012_Oct2017.shp: Fire Island, NY pre- and post-storm shoreline data from October 2012 to October 2017
Abstract:
Hurricane Sandy made U.S. landfall, coincident with astronomically high tides, near Atlantic City, New Jersey, on October 29, 2012. The storm, the largest on historical record in the Atlantic basin, affected an extensive area of the east coast of the United States. The highest waves and storm surge were focused along the heavily populated New York and New Jersey coasts. At the height of the storm, a record significant wave height of 9.6 meters (m) was recorded at the wave buoy offshore of Fire Island, New York (fig. 1, inset). During the storm, an overwash channel opened a breach in the location of Old Inlet, in the Otis Pike High Dunes Wilderness area. This breach is now referred to as the Wilderness Breach (fig. 1). Fire Island, New York is the site of a long term coastal morphologic change and processes project conducted by the U.S. Geological Survey (USGS). One of the objectives of the project was to understand the morphologic evolution of the barrier system on a variety of time scales (days - years - decades - centuries). In response to Hurricane Sandy, this effort continued with the intention of resolving storm impacts, post-storm beach response, and recovery. The day before Hurricane Sandy made landfall (October 28, 2012), a USGS field team conducted differential global positioning system (DGPS) surveys at Fire Island to quantify the pre-storm morphologic state of the beach and dunes. The area was re-surveyed after the storm, as soon as access to the island was possible. In order to fully capture the recovery of the barrier system, the USGS Hurricane Sandy Supplemental Fire Island Study was established to include collection in the weeks, months, and years following the storm. As part of the USGS Hurricane Sandy Supplemental Fire Island Study, the beach is monitored periodically to enable better understanding of post-Hurricane Sandy recovery. The alongshore state of the beach is recorded using a DGPS to collect data around the mean high water (MHW; 0.46 meters, North American Vertical Datum of 1988 [NAVD88]) to derive a shoreline, and the cross-shore response and recovery are measured along a series of 15 profiles. Monitoring continued in the weeks following Hurricane Sandy with additional monthly data collection through April 2013 and repeat surveys every 2-3 months thereafter until October 2014. Bi-annual surveys have been collected through September 2016. Beginning in October 2014 the USGS also began collecting shoreline data at the Wilderness Breach. See below for survey collection dates for all data types. For along shore shoreline data, the MHW shoreline (0.46 m [NAVD88]; Weber and others, 2005) is derived from the field data using an interpolation method that creates a series of equally-spaced cross-shore profiles between the two survey lines that flank the MHW contour. The foreshore slope is assumed to be uniform on each profile. Using this slope and the two surveyed positions on each cross-shore profile, a simple geometric calculation is done to find where each profile line intersects the MHW contour. This shapefile, FIIS_Shorelines_Oct2012_Oct2017.shp, consists of Fire Island, NY pre- and post-storm shoreline data collected from October 2012 to October 2017. This dataset contains 25 Mean High Water (MHW) shorelines for Fire Island, NY (A total of 23 full shorelines, where two shorelines were collected over multiple days). Prior to and following Hurricane Sandy in October 2012, continuous alongshore DGPS data were collected to assess the positional changes of the shoreline (MHW - 0.46 m NAVD88) and the upper portion of the beach. In the five years following Sandy, 24 surveys were conducted collecting data along shore-parallel tracks to capture the base of the dune, the mid-beach, and the upper and lower foreshore. The alongshore tracks extend from just west of Fire Island Lighthouse to the western flank of the storm-induced breach in the location of Old Inlet, in the Otis Pike High Dunes Wilderness area. Oct 28 2012 (MHW shoreline/Cross-shore data) Nov 01 2012 (MHW shoreline/Cross-shore data) Nov 04 2012 (Cross-shore data only) Dec 01 2012 (MHW shoreline/Cross-shore data) Dec 12 2012 (MHW shoreline/Cross-shore data) Jan 10 2013 (MHW shoreline/Cross-shore data) Feb 13 2013 (MHW shoreline/Cross-shore data) Mar 13 2013 (MHW shoreline/Cross-shore data) Apr 09 2013 (MHW shoreline/Cross-shore data) Jun 24 2013 (MHW shoreline/Cross-shore data) Sep 18 2013 (MHW shoreline/Cross-shore data) Dec 03 2013 (MHW shoreline/Cross-shore data) Jan 29 2014 (MHW shoreline/Cross-shore data) Jun 11 2014 (Cross-shore data only) Sep 09 2014 (MHW shoreline/Cross-shore data) Oct 07 2014 (Cross-shore data/Breach shoreline) Jan 21 2015 (MHW shoreline/Cross-shore data/Breach shoreline) Mar 19 2015 (MHW shoreline/Cross-shore data) May 16 2015 (MHW shoreline/Cross-shore data/Breach shoreline) Sep 28 2015 (MHW shoreline/Cross-shore data/Breach shoreline) Jan 21 2016 (MHW shoreline/Cross-shore data) Jan 25 2016 (MHW shoreline/Cross-shore data) Apr 06 2016 (Cross-shore data only) Apr 11 2016 (MHW shoreline/Cross-shore data/Breach shoreline) Jun 16 2016 (Cross-shore data only) Sep 27 2016 (MHW shoreline/Cross-shore data/Breach shoreline) Jan 24 2017 (MHW shoreline/Cross-shore data/Breach shoreline) May 23 2017 (MHW shoreline/Cross-shore data/Breach shoreline) Oct 17 2017 (MHW shoreline/Cross-shore data/Breach shoreline)
  1. How might this data set be cited?
    U.S. Geological Survey, 20180510, FIIS_Shorelines_Oct2012_Oct2017.shp: Fire Island, NY pre- and post-storm shoreline data from October 2012 to October 2017: U.S. Geological Survey Data Release doi:10.5066/P9ANYQ8G, U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida.

    Online Links:

    This is part of the following larger work.

    Henderson, Rachel Hehre, Hapke, Cheryl J., Brenner, Owen T., and Reynolds, B.J., 20150430, Hurricane Sandy Beach Response and Recovery at Fire Island, New York: Shoreline and Beach Profile Data, October 2012 to October 2014: U.S. Geological Survey Data Series DS 931, U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -73.228542
    East_Bounding_Coordinate: -72.896291
    North_Bounding_Coordinate: 40.724312
    South_Bounding_Coordinate: 40.627352
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 28-Oct-2012
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • String (25)
    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: -75.0
      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 meters
      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      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?
    FIIS_Shorelines_Oct2012_Oct2017
    This dataset includes vector shorelines representing an approximation of the MHW shoreline. Data were collected alongshore (just west of the Fire Island Lighthouse to the western flank of the storm-induced breach in the location of Old Inlet, in the Otis Pike High Dunes Wilderness area) to assess positional changes of the shoreline and the upper portion of the beach. (Source: U.S. Geological Survey)
    FID
    Internal feature number. (Source: Esri) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: Esri) Coordinates defining the features.
    DATE_
    Date assigned to MHW shoreline position; date of original survey as indicated on source material in the format mm/dd/yyyy. (Source: USGS) Character string of length 10. Date expressed as mm/dd/yyyy.
    UNCERT
    Estimate of shoreline position uncertainty. Actual shoreline position is expected to be within the range of this value (plus or minus, meters). See the section on horizontal positional accuracy for more detailed description. (Source: USGS)
    Range of values
    Minimum:0.8
    Maximum:7.8
    YEAR_
    Year of shoreline collection. (Source: USGS)
    Range of values
    Minimum:2012
    Maximum:2017
    Units:year
    Agency
    Originator agency of material used to derive shoreline. (Source: USGS) Character string of length 20
    Proxy
    Method used to determine shoreline. (Source: USGS)
    ValueDefinition
    MHW - interpolated from bounding alongshore lines or MHW - extracted from surfaceMethod used to determine shoreline location determined by available data.
    Data_Sourc
    Source (type) of data used to generate the shoreline. (Source: USGS)
    ValueDefinition
    DGPS Post Sandy Field Data CollectionShoreline data collected by USGS with differential GPS survey.
    NOTES_
    Notes about each shoreline, including a description of coverage and data gaps alongshore. (Source: USGS) Character string of length 150
    Originator
    The person or persons responsible for interpreting the tabular field data to the MHW shoreline. (Source: USGS) Character string of length 100
    SHAPE_Leng
    Length of feature, in meters (UTM zone 18N NAD 83), automatically calculated by Esri software in the geodatabase. (Source: Esri)
    Range of values
    Minimum:6201.007
    Maximum:30001.101

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • U.S. Geological Survey
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida
    Attn: Rachel E. Henderson (Hehre)
    600 4th Street South
    St. Petersburg, FL
    USA

    (727)-502-8000 (voice)
    rehenderson@usgs.gov

Why was the data set created?

The U.S. Geological Survey (USGS) mounted a substantial effort in response to Hurricane Sandy including an assessment of the morphological impacts to the beach and dune system at Fire Island, New York. Field surveys of the beach and dunes collected just prior to and after the U.S. landfall, which occurred on October 29th, 2012, were used to quantify change in several focus areas. The migration of the shoreline through time is assessed by quantifying the net shoreline movement (NSM) over different time periods, using the interpolated MHW shorelines and 50 m spaced transects in the Digital Shoreline Analysis System (DSAS; Thieler and others, 2009).

How was the data set created?

  1. From what previous works were the data drawn?
    DGPS DATA DATE (source 1 of 1)
    Reynolds, B.J., Brenner, Owen T., and Hapke, Cheryl J., Unpublished material, FIIS DGPS shoreline data.

    Other_Citation_Details:
    In order to examine the dynamics of the shoreline from Hurricane Sandy and monitor the continued response and recovery, surveys of continuous alongshore DGPS data were collected in conjunction with cross-shore profiles. Multiple shore-parallel tracks were driven to capture the base of the dune, the mid-beach, and the upper and lower foreshore along the length of the island from Fire Island lighthouse to the western side of the storm-induced inlet breach at Old Inlet. Initial surveys were conducted one day prior to landfall and immediate post-storm surveys were conducted over the three days following Hurricane Sandy. The beaches and dunes were resurveyed monthly from December 2012 through April 2013, and bi-monthly surveys are presently ongoing. The USGS is continuing to monitor the beaches and dunes to evaluate how much of the sand removed by Sandy returns to the beach via natural beach-building processes.
    Type_of_Source_Media: .csv file
    Source_Contribution:
    Tabular DGPS data (collected in ASCII format) was converted to vector digital data and edited using Esri ArcMap v 10.5 to publish shoreline data in a GIS environment.
  2. How were the data generated, processed, and modified?
    Date: 30-Jan-2014 (process 1 of 6)
    Interpolated MHW Shoreline generation from tabular DGPS Data (October 28, 2012 to December 2013) Continuous alongshore DGPS data were collected to assess the positional changes of the MHW shoreline and the upper portion of the beach. Data were collected along shore-parallel tracks to capture the base of the dune, the mid-beach, and the upper and lower foreshore. For each survey date, ASCII point data were imported into Matlab (v R2012a) and processed as follows:
    For surveys October 28, 2012 through December 2013, the MHW shoreline (0.46 m North American Vertical Datum of 1988 [NAVD88]) is derived from the field data by using an interpolation method that creates a series of equally-spaced cross-shore profiles between the two survey lines that flank the MHW contour. The foreshore slope is assumed to be uniform on each profile. Using this slope and the two surveyed positions on each cross-shore profile, a simple geometric calculation is done to find where each profile line intersects the MHW contour. At this intersection a point is generated, and the series of points making up the MHW shoreline are appended to create a polyline shoreline. The resulting polyline shapefile was named FIIS_shoreline_DATE, where date is the date of the field survey. For example: MHW extracted polyline for October 28, 2012 would be named FIIS_shoreline_2012Oct28.shp Person who carried out this activity:
    U.S. Geological Survey - Woods Hole Coastal & Marine Science Center
    Attn: Amy Farris
    384 Woods Hole Road
    Woods Hole, MA
    USA

    508-457-2288 (voice)
    508-547-2310 (FAX)
    afarris@usgs.gov
    Data sources used in this process:
    • DGPS DATA DATE
    Data sources produced in this process:
    • FIIS_Shorlines_DATE
    Date: 15-Mar-2018 (process 2 of 6)
    Extracted MHW Shoreline generation from tabular DGPS Data (January 2014 to October 2017)
    Continuous alongshore DGPS data were collected to assess the positional changes of the MHW shoreline and the upper portion of the beach. Data were collected along shore-parallel tracks to capture the base of the dune, the mid-beach, and the upper and lower foreshore. For each survey date, ASCII point data were imported into ArcMap as point data. Starting in January of 2014, and applying to all subsequent surveys, a new survey approach was implemented that was designed to improve surface interpolation by collecting a denser network of XYZ (UTMX, UTMY, and elevation) points along the beach face. For these surveys, alongshore transects are collected at the berm crest, low water mark and mid-beach face. In addition, a sinusoidal transect is collected by driving from the water's edge to the top of the berm crest at approximately 45 degrees to the orientation of the shoreline. The XYZ data are used to create an interpolated surface from which the MHW contour is extracted.
    The resulting polyline shapefile was named FIIS_shoreline_DATE, where date is the date of the field survey. For example: MHW extracted polyline for October 28, 2012 would be named FIIS_shoreline_2012Oct28.shp Person who carried out this activity:
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida
    Attn: Rachel E. Henderson (Hehre)
    600 4th Street South
    St. Petersburg, FL
    USA

    (727)-502-8000 (voice)
    rehenderson@usgs.gov
    Data sources used in this process:
    • DGPS DATA DATE
    Data sources produced in this process:
    • FIIS_Shorlines_DATE
    Date: 10-Apr-2018 (process 3 of 6)
    The shoreline file FIIS_Shorlines_DATE was coded with attribute fields: FID, DATE_, and UNCERT (Uncertainty). These fields are required for the Digital Shoreline Analysis System (DSAS), which was used to calculate shoreline change rates. Additional fields: Year_, Agency, Proxy, Data_Source, Notes_, Originator_, and SHAPE_Leng were added to comply with the existing historical shoreline shapefile database for Fire Island. Agency refers to the contact organization (ex: USGS, NPS), Proxy is the shoreline proxy used to derive the shoreline (ex: MHW, HWL), Data_Source is the material or source of the shoreline data (ex: lidar, air photos, GPS), Notes_ indicates the extent of the shoreline data along Fire Island, and the Originator_ attribute is the contact organization responsible for the generation of the shoreline. Person who carried out this activity:
    U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center
    Attn: Rachel E. Henderson (Hehre)
    600 4th Street South
    St. Petersburg, FL
    USA

    (727)-502-8000 (voice)
    rehenderson@usgs.gov
    Date: 01-Apr-2018 (process 4 of 6)
    Calculation of shoreline uncertainty: In order to determine the uncertainties associated with individual shorelines, a methodology following Morton and Miller (2005) and Hapke and others, (2006) was used to estimate a positional error value for each shoreline. The shoreline position uncertainty is estimated using a square root of the sum of the squares of multiple terms. Total shoreline positional error is a function of the errors inherent in the source data/data collection, and those errors generated in the creation and identification of the vector shoreline. The two different methods of shoreline generation, "interpolated" and "extracted" are described in the preceding process steps. The uncertainty calculations for Mean High Water (MHW) shoreline generation are as follows:
    INTERPOLATED MHW SHORELINES: Oct 2012 to Dec 2013 The terms used for the interpolated shorelines derived from October 2012 to December 2013 were: 1) Predicted MHW uncertainty - an estimate of interpolated shoreline position accuracy based on the slope, and distance between track lines (average of 0.8 to 2.5 m); 2) Average measured MHW error - the positional difference between the interpolated MHW shoreline and the location of the MHW elevation on the cross-shore profiles from the same survey date (average offset ranges from 0.9 to 7.5 m); 3) Collection and equipment error - derived from static portions of each survey (average offset ranges from 0.07 to 0.12 m); 4) A term to account for horizontal positional variation found when driving the GPS (horizontal to the Polaris) on a sloped surface (0.01 to 0.02 m).
    EXTRACTED MHW SHORELINES: Jan 2014 to Sep 2016 For surveys January 2014 to Sept 2016 the MHW elevation was extracted from a surface generated from field collected data points. The terms used to estimate error for the extracted shorelines were: 1) Average measured MHW - the positional difference between the interpolated MHW shoreline and the location of the MHW elevation on the cross-shore profiles from the same survey date (average offset ranges from 0.8 to 4.5 m) 2) Collection and equipment error - derived from static portions of each survey (0.01 to 0.11 m); and 3) Uncertainty of the interpolated surface estimated by withholding 10% of the original data points and calculating a root mean square error (RMSE) of the difference between the withheld points and the surface (0.02 to 0.06 m). Uncertainty values for individual shorelines can be found in the shapefile "UNCERT" attribute and in the Horizontal Positional Accuracy Explanation of this metadata file. Person who carried out this activity:
    U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center
    Attn: Rachel E. Henderson (Hehre)
    600 4th Street South
    St. Petersburg, FL
    USA

    (727)-502-8000 (voice)
    rehenderson@usgs.gov
    Date: 01-Apr-2018 (process 5 of 6)
    In ArcMap (v.10.5) the calculated uncertainty rates were added to the attribute field "UNCERT" for each shoreline shapefile for use with the Digital Shoreline Analysis System (DSAS v.4.0) software to perform rate calculations. Person who carried out this activity:
    U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center
    Attn: Rachel E. Henderson (Hehre)
    600 4th Street South
    St. Petersburg, FL
    USA

    (727)-502-8000 (voice)
    rehenderson@usgs.gov
    Date: 10-Apr-2018 (process 6 of 6)
    All shorelines were appended into one feature class (in a personal geodatabase). ArcToolbox>>Data Management Tools>>General>>Append: select each FIIS_shoreline_DATE polyline shapefile. Features were exported from the geodatabase to shoreline shapefiles for each survey date. Shorelines for the following dates were appended to a single shapefile: Oct 28 2012 Nov 01 2012 Nov 02 2012 Dec 01 2012 Dec 12 2012 Dec 13 2012 Jan 10 2013 Feb 12 2013 Mar 13 2013 Apr 09 2013 Jun 24 2013 Sep 19 2013 Dec 03 2013 Jan 30 2014 Sep 09 2014 Jan 21 2015 May 16 2015 Sep 30 2015 Jan 22 2016 Jan 26 2016 Apr 12 2016 Sep 28 2016 Jan 26 2017 May 25 2017 Oct 18 2017 Person who carried out this activity:
    U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center
    Attn: Rachel E. Henderson (Hehre)
    600 4th Street South
    St. Petersburg, FL
    USA

    (727)-502-8000 (voice)
    rehenderson@usgs.gov
    Data sources used in this process:
    • FIIS_Shorlines_DATE
    Data sources produced in this process:
    • FIIS_Shorelines_Oct2012_Oct2017
  3. What similar or related data should the user be aware of?
    Hapke, C.J., Himmelstoss, E.A., Kratzmann, M.G., List, J.H., and Thieler, E.R., 2010, National Assessment of Shoreline Change: Historical Shoreline Change along the New England and Mid-Atlantic Coasts: U.S. Geological Survey Open-File Report 2010-1118, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal & Marine Science Center, Woods Hole, MA.

    Online Links:

    Thieler, E.R., Himmelstoss, E.A., Zichichi, J.L., and Ergul, A., 2009, Digital Shoreline Analysis System (DSAS) version 4.0 - An ArcGIS extension for calculating shoreline change: U.S. Geological Survey Open-File Report 2008-1278, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal & Marine Science Center, Woods Hole, MA.

    Online Links:

    Other_Citation_Details: Current version of software at time of use was 4.3
    Morton, R. A., and Miller, T.L., 2005, National assessment of shoreline change: Part 2 Historical shoreline changes and associated coastal land loss along the U.S. Southeast Atlantic Coast: U.S. Geological Survey Open-File Report 2005-1401, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal & Marine Science Center, Woods Hole, MA.

    Online Links:

    Hapke, C.J., Reid, D., Richmond, B.M., Ruggiero, P., and List, J., 2006, National assessment of shoreline change Part 3: Historical shoreline change and associated coastal land loss along the sandy shorelines of the California coast: U.S. Geological Survey Open-File Report 2006-1219, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal & Marine Science Center, Woods Hole, MA.

    Online Links:

    Other_Citation_Details: none
    Weber, K.M., List, J.H., and Morgan, K.L.M., 20050101, An Operational Mean High Water Datum for Determination of Shoreline Position from Topographic Lidar Data: U.S. Geological Survey Open-File Report 2005-1027, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal & Marine Science Center, Woods Hole, MA.

    Online Links:

    Henderson, Rachel E., Hapke, Cheryl J., Brenner, Owen T., and Reynolds, B.J., 20170414, Hurricane Sandy beach response and recovery at Fire Island, New York: Shoreline, beach profile data, and beach shoreline data: October 2012 to September 2016: U.S. Geological Survey Data Release doi:10.5066/F7G15Z17, U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida.

    Other_Citation_Details:
    Suggested Citation: Henderson, R.E., Hapke, C.J., Brenner, O.T., and Reynolds, B.J., 2017, Hurricane Sandy beach response and recovery at Fire Island, New York: Shoreline, beach profile data, and breach shoreline data: October 2012 to September 2016: U.S. Geological Survey data release, https:// doi.org/10.5066/F7G15Z17.

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

  1. How well have the observations been checked?
    The data provided here is a compilation of shorelines that were derived using USGS-specific field-collection methods over the course of four years following Hurricane Sandy, which made landfall in New Jersey on October 29, 2012. The table attributes associated with FIIS_Shorelines_Oct2012_Oct2017.shp are based on the requirements of the Digital Shoreline Analysis System (DSAS) software and have gone through a series of quality assurance procedures. For more information, see https://woodshole.er.usgs.gov/project-pages/DSAS/.
  2. How accurate are the geographic locations?
    In order to determine the uncertainties associated with individual shorelines, a methodology following Morton and Miller (2005) and Hapke and others, (2006) was used to estimate a positional error value for each shoreline. The shoreline position uncertainty is estimated using a square root of the sum of the squares of multiple terms. Total shoreline positional error is a function of the errors inherent in the source data/data collection, and those errors generated in the creation and identification of the vector shoreline. The two different methods of shoreline generation, "interpolated" and "extracted" are described in the process steps. The uncertainty calculations for Mean High Water (MHW) shoreline generation are as follows:
    INTERPOLATED MHW SHORELINES: Oct 2012 to Dec 2013 The terms used for the interpolated shorelines derived from October 2012 to December 2013 were: 1) Predicted MHW uncertainty - an estimate of interpolated shoreline position accuracy based on the slope, and distance between track lines (average of 0.8 to 2.5 m); 2) Average measured MHW error - the positional difference between the interpolated MHW shoreline and the location of the MHW elevation on the cross-shore profiles from the same survey date (average offset ranges from 0.9 to 7.5 m); 3) Collection and equipment error - derived from static portions of each survey (average offset ranges from 0.07 to 0.12 m); 4) A term to account for horizontal positional variation found when driving the GPS (horizontal to the Polaris) on a sloped surface (0.01 to 0.02 m).
    EXTRACTED MHW SHORELINES: Jan 2014 to Oct 2017
    For surveys January 2014 to October 2017 the MHW elevation was extracted from a surface generated from field collected data points. The terms used to estimate error for the extracted shorelines were: 1) Average measured MHW - the positional difference between the interpolated MHW shoreline and the location of the MHW elevation on the cross-shore profiles from the same survey date (average offset ranges from 0.8 to 4.5 m) 2) collection and equipment error - derived from static portions of each survey (0.01 to 0.11 m); and 3) uncertainty of the interpolated surface estimated by withholding 10% of the original data points and calculating a root mean square error (RMSE) of the difference between the withheld points and the surface (0.02 to 0.06 m). Uncertainty values for individual shorelines can be found in the shapefile's UNCERT attribute and in the Horizontal Positional Accuracy Explanation of this metadata file.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    This shoreline file is complete and contains all shoreline segments derived from pre- and post-Hurricane Sandy data collection efforts. These data adequately represented the shoreline position at the time of the survey.
  5. How consistent are the relationships among the observations, including topology?
    Adjacent shoreline segments do not overlap and are not necessarily continuous. Shorelines were quality checked for accuracy.

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 as the originator of the dataset.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    rehenderson@usgs.gov
  2. What's the catalog number I need to order this data set? FIIS_Shorelines_Oct2012_Oct2017.shp
  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. Any use of trade, product, or firm 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?

Who wrote the metadata?

Dates:
Last modified: 30-May-2018
Metadata author:
U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida
Attn: Rachel E. Henderson (Hehre)
600 4th Street South
St. Petersburg, FL
USA

Contact_Voice_Telephone (voice)
rehenderson@usgs.gov
Hours_of_Service: 0800-1600 Eastern Time
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/FIIS_Shorelines_metadata.faq.html>
Generated by mp version 2.9.49 on Mon Sep 10 17:44:28 2018