Mean tidal range in salt marsh units of Edwin B. Forsythe National Wildlife Refuge, New Jersey (polygon shapefile)

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Frequently anticipated questions:

What does this data set describe?

Title:
Mean tidal range in salt marsh units of Edwin B. Forsythe National Wildlife Refuge, New Jersey (polygon shapefile)
Abstract:
Biomass production is positively correlated with mean tidal range in salt marshes along the Atlantic coast of the United States of America. Recent studies support the idea that enhanced stability of the marshes can be attributed to increased vegetative growth due to increased tidal range. This dataset displays the spatial variation mean tidal range (i.e. Mean Range of Tides, MN) in the Edwin B. Forsythe National Wildlife Refuge (EBFNWR), which spans over Great Bay, Little Egg Harbor, and Barnegat Bay in New Jersey, USA. MN was based on the calculated difference in height between mean high water (MHW) and mean low water (MLW) using the VDatum (v3.5) software (http://vdatum.noaa.gov/). The input elevation was set to zero in VDatum to calculate the relative difference between the two datums.
As part of the Hurricane Sandy Science Plan, the U.S. Geological Survey has started a Wetland Synthesis Project to expand National Assessment of Coastal Change Hazards and forecast products to coastal wetlands. The intent is to provide federal, state, and local managers with tools to estimate their vulnerability and ecosystem service potential. For this purpose, the response and resilience of coastal wetlands to physical factors need to be assessed in terms of the ensuing change to their vulnerability and ecosystem services. EBFNWR was selected as a pilot study area.
  1. How might this data set be cited?
    Defne, Zafer, and Ganju, Neil K., 2016, Mean tidal range in salt marsh units of Edwin B. Forsythe National Wildlife Refuge, New Jersey (polygon shapefile): data release DOI:10.5066/F7CF9N7X, U.S. Geological Survey, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Defne, Zafer, and Ganju, Neil K., 2016, Mean tidal range in salt marsh units of Edwin B. Forsythe National Wildlife Refuge, New Jersey: data release DOI:10.5066/F7CF9N7X, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Defne, Z., and Ganju, N.K.,2016, Mean tidal range in salt marsh units of Edwin B. Forsythe National Wildlife Refuge, New Jersey: U.S. Geological Survey data release, https://doi.org/10.5066/F7CF9N7X
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -74.484623118
    East_Bounding_Coordinate: -74.051158122
    North_Bounding_Coordinate: 40.053798801
    South_Bounding_Coordinate: 39.435117592
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/580a28f3e4b0f497e7906379?name=mu_MN_EBFNWRp.png (PNG)
    Graphic that shows the mean tidal range projected on the conceptual marsh units of EBFNWR salt marsh complex overlaying Esri Shaded World Relief Map.
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2016
    Currentness_Reference:
    publication date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: Vector Digital Data Set (Polygon)
  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):
      • G-polygon (1338)
    2. What coordinate system is used to represent geographic features?
      The map projection used is WGS 1984 Web Mercator Auxiliary Sphere (ESRI Full Name: WGS_1984_Web_Mercator_Auxiliary_Sphere).
      Projection parameters:
      Standard_Parallel: 0.0
      Longitude_of_Central_Meridian: 0.0
      False_Easting: 0.0
      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_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257223563.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: Mean_Sea_Level
      Altitude_Resolution: 0.01
      Altitude_Distance_Units: Meter
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    mu_MN_EBFNWRp
    Attribute information associated with the mean tidal range projected on the conceptual marsh units of EBFNWR salt marsh complex. (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.
    FID_CMU
    Sequential unique whole numbers that represents the identification number for each conceptual marsh units. (Source: USGS)
    Range of values
    Minimum:0
    Maximum:1337
    MIN
    Minimum value of mean tidal range (MHW to MLW) within a marsh unit (Source: USGS)
    Range of values
    Minimum:0.0935889035463
    Maximum:1.21910452843
    Units:meters
    MAX
    Maximum value of mean tidal range (MHW to MLW) within a marsh unit (Source: USGS)
    Range of values
    Minimum:0.0937732234597
    Maximum:1.2198830843
    Units:meters
    MEAN
    Mean value of mean tidal range (MHW to MLW) within a marsh unit (Source: USGS)
    Range of values
    Minimum:0.093665617145
    Maximum:1.21952922612
    Units:meters
    STD
    Standard deviation of mean tidal range (MHW to MLW) within a marsh unit (Source: USGS)
    Range of values
    Minimum:0
    Maximum:0.108876861292
    Units:meters
    Entity_and_Attribute_Overview:
    In this dataset, mean tidal range (i.e. Mean Range of Tides, MN between MHW and MLW) as calculated by the VDatum software is averaged over the previously defined conceptual marsh units in the salt marsh complex EBFNWR. Decimal values in the attribute table are a result of double precision calculations while significant digits are considered in defining the attribute measurement resolutions. Therefore, the smallest unit increment for calculated tidal range values can be assumed to be a practical value such as 0.01 m.
    Entity_and_Attribute_Detail_Citation: USGS

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Zafer Defne
    • Neil K. Ganju
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    U.S. Geological Survey
    Attn: Zafer Defne
    Ocean Scientist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2254 (voice)
    508-457-2310 (FAX)
    zdefne@usgs.gov

Why was the data set created?

Analysis of mean tidal range is part of a comprehensive assessment to identify the factors and their weights in determining the vulnerability and resiliency of salt marshes. The results are summarized over the previously determined conceptual salt marsh unit polygons with this dataset.

How was the data set created?

  1. From what previous works were the data drawn?
    marshUnitsEBFp (source 1 of 1)
    U.S. Geological Survey, 2016, Conceptual salt marsh units for wetland synthesis: Edwin B. Forsythe National Wildlife Refuge, New Jersey: data release DOI:10.5066/F7QV3JPG, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    Downloaded and used the features in [marshUnitsEBFp.shp] to summarize the mean tidal range at each marsh unit
  2. How were the data generated, processed, and modified?
    Date: 2016 (process 1 of 8)
    All process steps were performed by Zafer Defne, in ArcMap (ver. 10.3.1) using tools from ArcToolbox, unless otherwise stated. Names of specific tools used are given in CAPITAL letters (any critical parameters used is given in parentheses, separated by a semicolon, immediately after the tool name). Input and output file names are provided in [square brackets] when necessary. Units for length and area calculations are meters (m) and square meters (m2) unless otherwise stated. Generate a point cloud of coordinates indicating calculation locations for the mean range of tides (MN).
    a) CREATE CONSTANT RASTER(Constant value= 1; Output cell size: 0.003 degrees) that surpasses the EBFNWR boundaries.
    b) RASTER TO POINT to generate an array of points [pts.shp].
    c) Export point coordinates to an Excel table [contPts.xls]. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Zafer Defne
    Ocean Scientist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-458-8700 x2254 (voice)
    508-457-2310 (FAX)
    zdefne@usgs.gov
    Data sources produced in this process:
    • contPts.xls
    Date: 2016 (process 2 of 8)
    Establish marsh unit boundaries.
    DISSOLVE(Dissolve Fields= FID_CMU) features in marsh units layer based on the attribute identification numbers. FID_CMU is the unique identifier for each marsh unit. Data sources used in this process:
    • marshUnitsEBFp
    Data sources produced in this process:
    • mu
    Date: 2016 (process 3 of 8)
    Calculate Mean Range of Tides with VDatum (v3.5) http://vdatum.noaa.gov/.
    a) Create a point cloud with 10 arc sec (~300 meters) spacing to calculate the mean range of tides (MN). This comma separated file includes columns for latitude, longitude and height (set to zero).
    b) Input point cloud file to VDatum. Set COORDINATE SYSTEM (Geographic), HORIZONTAL DATUM (NAD83), VERTICAL UNIT (meters), HEIGHT/SOUNDING (height) options same for the input and output. Set VERTICAL DATUM for input and output MHW and MLW, respectively. The choice of horizontal datum is to facilitate conversion between tidal datums, and it has no effect on the input/output dataset because it is identical for both of them.
    c) After running VDatum, remove missing data (-99999) from the output dataset. Data sources used in this process:
    • contPts.xls
    Data sources produced in this process:
    • MN.csv
    Date: 2016 (process 4 of 8)
    Create a raster surface dataset from the feature points.
    a) Import points from [MN.csv] to ArcMap using MAKE XY EVENT LAYER.
    b) Create a raster surface with inverse distance weighting in Spatial Analyst toolbox. IDW.SpatialAnalyst(Output Cell Size=0.0003 deg; ; Power=2; Search Radius=Variable; Number of Points=12) to obtain [mn_idw_triEbf.tif]. Data sources used in this process:
    • MN.csv
    Data sources produced in this process:
    • mn_idw_mu.tif
    Date: 2016 (process 5 of 8)
    Clip the raster to marsh boundaries. A buffer zone is created around the marsh boundaries to facilitate alternative interpolation and clipping options in future studies.
    a) Create 250 m buffer around the marsh polygon [mu.shp] to create a clipping mask [mu_buff250m.shp]. BUFFER(Side type= Full; Method =Geodesic; Dissolve type= All).
    b) Clip the raster clipping mask. EXTRACT BY MASK to obtain [MN_EBFNWR.tif]. Data sources used in this process:
    • mu
    • MN_idw.tif
    Data sources produced in this process:
    • MN_EBFNWR.tif
    Date: 2016 (process 6 of 8)
    PROJECT RASTER(Input raster= MN_EBFNWR.tif; Output raster= MN_EBFNWRp.tif; Input coordinate system= GCS_WGS_1984; Output coordinate system= WGS_1984_Web_Mercator_Auxiliary_Sphere; Resampling technique= Nearest; Output cell size= 30 meters) to obtain [MN_EBFNWRp.tif]. Data sources used in this process:
    • MN_EBFNWR.tif
    Data sources produced in this process:
    • MN_EBFNWRp.tif
    Date: 2016 (process 7 of 8)
    Calculate values for each marsh unit. a) Clip the raster with the marsh units polygon by using EXTRACT BY MASK(Cell Size=0.00003) to obtain [mn_idw_mu.tif]. Cell size for raster analysis was reduced from 3e-4 to 3e-5 degrees to have smoother boundaries.
    b) ZONAL STATISTICS AS TABLE(Feature Zone Data=[mu]; zone field=FID_CMU; Value Raster=[mn_idw_mu.tif]; Output Table=muMeanTidalRange; Statistics type=ALL)
    c) ADD JOIN(Layer name=[mu]; Input join field=FID_CMU; Join Table=muMeanTidalRange; Output join field=FID_CMU) to marsh units layer based on the "FID_CMU" field
    d)Export dataset as a shapefile [mu_MN_EBFNWRp.shp] and keep the 'MIN", 'MAX', "MEAN" and "STD" fields from the join operation. Data sources used in this process:
    • mu
    • mn_idw_mu.tif
    Data sources produced in this process:
    • mu_MN_EBFNWRp.shp
    Date: 10-Aug-2020 (process 8 of 8)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
  3. What similar or related data should the user be aware of?
    NOAA, 2016, VDatum (v3.5): NOAA, Silver Spring, MD.

    Online Links:

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

  1. How well have the observations been checked?
    Water-land boundary and marsh unit boundaries inherit accuracy from the source data (see source information in lineage section), conceptual marsh units. Mean Range of Tides is calculated with the VDatum software then interpolated on a raster surface and averaged at each marsh unit.
  2. How accurate are the geographic locations?
    Horizontal accuracy for the polygon boundaries is inherited from the source layer, conceptual marsh units, and considered to be greater than 3 meters. The point cloud used for calculating tidal range with VDatum had ~300-meter resolution that was interpolated over a 3-meter raster prior to clipping and calculating the mean value for each mash unit. The overall horizontal positional accuracy is expected to be on the order of 3 meters.
  3. How accurate are the heights or depths?
    The maximum cumulative uncertainty for the New Jersey - Coastal embayments operational VDatum region is given as 9.2 centimeters. See Estimation of Vertical Uncertainties in VDatum for more information (https://vdatum.noaa.gov/docs/est_uncertainties.html#estTidalDatum).
  4. Where are the gaps in the data? What is missing?
    The boundaries of this dataset were created by expanding the outline boundaries of polygons created with a 250 meter exterior buffer around the source data, conceptual marsh units, which include: 1) Marsh Salt, 2) Wetland Scrub Shrub Salt, and 3) channels of Open Water Salt that are not wider than 50 meters. Any polygons with an area smaller than 50 square meters were omitted in the source dataset.
  5. How consistent are the relationships among the observations, including topology?
    Polygons do not overlap.

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 The mean tidal range in this data set are defined for scientific research purposes and should not be used as a sole source of reference for any regulations and policy making. Not suitable for navigation. Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey 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

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? mu_MN_EBFNWRp.shp (together with shapefile components, browse graphic, and associated FGDC CSDGM metadata in XML, TEXT, FAQ, and HTML formats with the same file name).
  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. Not for navigational use.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 19-Mar-2024
Metadata author:
U.S. Geological Survey
Attn: Zafer Defne
Ocean Scientist
384 Woods Hole Road
Woods Hole, MA

508-548-8700 x2254 (voice)
508-457-2310 (FAX)
whsc_data_contact@usgs.gov
Contact_Instructions:
The metadata contact email address is a generic address in the event the person is no longer with USGS. (updated on 20240319)
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/SB_data_release/DR_F7CF9N7X/mu_MN_EBFNWRp.faq.html>
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