Ground-Based XYZ Point Elevation Data Collected in May 2015 From Fire Island, New York

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Frequently anticipated questions:

What does this data set describe?

Title:
Ground-Based XYZ Point Elevation Data Collected in May 2015 From Fire Island, New York
Abstract:
Scientists from the U.S. Geological Survey St. Petersburg Coastal and Marine Science Center in St. Petersburg, Florida, conducted a bathymetric survey of Fire Island, New York, from May 6 to 20, 2015. The U.S. Geological Survey is involved in a post-Hurricane Sandy effort to map and monitor the morphologic evolution of the wilderness breach as a part of the Hurricane Sandy Supplemental Project GS2-2B. During this study, bathymetry data were collected with single-beam echosounders and Global Positioning Systems, which were mounted to personal watercraft, along the Fire Island shoreface and within the wilderness breach. Additional bathymetry and elevation data were collected using backpack Global Positioning Systems on flood shoals and in shallow channels within the wilderness breach.
  1. How might this data set be cited?
    U.S. Geological Survey, 20170424, Ground-Based XYZ Point Elevation Data Collected in May 2015 From Fire Island, New York: U.S. Geological Survey Data Series DS 1049, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL.

    Online Links:

    This is part of the following larger work.

    Nelson, Timothy R., Miselis, Jennifer L., Hapke, Cheryl J., Brenner, Owen T., Henderson, Rachel E., Reynolds, Billy J., and Wilson, Kathleen E., 20170424, Coastal bathymetry data collected in May 2015 from Fire Island, New York: The wilderness breach and shoreface: U.S. Geological Survey Data Series DS 1049, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -72.90793139
    East_Bounding_Coordinate: -72.88394551
    North_Bounding_Coordinate: 40.73824263
    South_Bounding_Coordinate: 40.72281912
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 06-May-2015
    Ending_Date: 20-May-2015
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: Tabular digital 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):
      • Point (69,557)
    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: 0.999600
      Longitude_of_Central_Meridian: -75.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000
      Planar coordinates are encoded using row and column
      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 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222101.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: North American Vertical Datum 1988
      Altitude_Resolution: 0.001 m
      Altitude_Distance_Units: meter
      Altitude_Encoding_Method: Attribute values
  7. How does the data set describe geographic features?
    201505_Ground_Based_XYZ.csv
    Comma-delimited x,y,z file containing location, elevation, and date information collected with backpack GPS systems (Source: U.S. Geological Survey)
    Easting_m
    NAD83 UTM x-axis coordinate (Zone 18) (Source: U.S. Geological Survey)
    Range of values
    Minimum:676685
    Maximum:678673
    Units:Meter
    Northing_m
    NAD83 UTM y-axis coordinate (Zone 18N) (Source: U.S. Geological Survey)
    Range of values
    Minimum:4510140
    Maximum:4511806
    Units:Meter
    elevation
    z-value (elevation) in NAVD88 (Source: U.S. Geological Survey)
    Range of values
    Minimum:-5.678
    Maximum:2.089
    Units:Meter
    Date
    Coordinated Universal Time (UTC) date of sample collection (Source: U.S. Geological Survey)
    Range of values
    Minimum:05/17/2015
    Maximum:05/19/2015
    Entity_and_Attribute_Overview:
    Comma-delimited x,y,z file containing UTM X, UTM Y locations and corresponding Z-elevation values, all in meters, as well as date of sample collection.
    Entity_and_Attribute_Detail_Citation:
    Nelson, T.R., Miselis, J.L., Hapke, C.J., Brenner, O.T., Henderson, R.E., Reynolds, B.J., Wilson, K.E., 20175, Coastal Bbathymetry Ddata Ccollected in May 2015 from Fire Island, New York—: tThe Wwilderness Bbreach and Sshoreface: U.S. Geological Survey Data Series ###, https://dx.doi.org/10.3133/ds###.

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
    Attn: Timothy R. Nelson
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8098 (voice)
    727-502-8182 (FAX)
    trnelson@usgs.gov

Why was the data set created?

To determine the change Hurricane Sandy caused to the shoreface morphology and breach evolution at Fire Island, New York, USA, scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center (SPCMSC) conducted a bathymetric survey of Fire Island from May 6 to 20, 2015. The objectives of the data collection were to map the morphology of the shoreface and the wilderness breach as part of the USGS Hurricane Sandy Supplemental Project GS2-2B. This dataset, 201505_Ground_Based_XYZ.zip, consists of elevation data collected with a backpack GPS system from subaerial and shallow flood shoals.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 2015 (process 1 of 6)
    Process Description: GPS Acquisition: GPS base stations were erected at benchmarks REST (near the town of Robins Rest) and U374 (NGS benchmark Permanent Identification number (PID#) KU0206) located on Fire Island. The base stations were equipped with Ashtech ProFlex 500 Global Navigation Satellite System (GNSS) receivers. The survey personal watercraft (PWC) (rovers) were equipped with ProFlex 500 GNSS receivers. The base and rover receivers recorded their positions concurrently at 10 Hertz (Hz) throughout the survey. Reference station coordinates were verified with Continuously Operating Reference Station (CORS) sites using the Online Positioning User Service (OPUS), available at http://www.ngs.noaa.gov/OPUS/. U374 used reference stations ZNY1, NYRH, CTDA;, REST used stations NYCI, NYRH, and MOR6, and the VC base used MOR6, CTGU, AND NYRH. OPUS- computed reference stations had horizontal errors of 0.4 cm for REST, 0.5 cm for U374, and 0.3 cm for VC. Vertical errors were 0.2 cm for REST, 0.3 cm for U374, and 1.5 cm for VC. Person who carried out this activity:
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    Attn: Billy J. Reynolds
    Engineering Technician
    600 4th St. S
    St. Petersburg, FL
    USA

    727-502-8067 (voice)
    727-502-8181 (FAX)
    breynolds@usgs.gov
    Date: 2015 (process 2 of 6)
    Ground-Based Mapping: Elevation data were collected using two Ashtech Z-Xtreme GPS receivers mounted in SECO backpacks with Ashtech Marine antennas attached to a pole extending above the head of the surveyor. The elevation of the antennas relative to the ground was measured for each surveyor in a walking stride position (varying between 2.07 and 2.10 m). The surveyors did not follow a pre-defined path but collected data over as much of the subaerial and shallow shoals and beach as possible during low tide. Person who carried out this activity:
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    Attn: Owen T. Brenner
    Geologist
    600 4th St. S
    St. Petersburg, FL
    USA

    727-502-8085 (voice)
    727-502-8182 (FAX)
    obrenner@usgs.gov
    Date: 2015 (process 3 of 6)
    Ground-Based Differentially Corrected Navigation Processing: Locations associated with backpack position were postprocessed using a differential correction derived from the base/rover setup. The base-station coordinates were imported into GrafNav version 8.5 (Waypoint Product Group) and the GPS data from the backpack surveys were processed to the concurrent GPS session data at the base stations. The horizontal and vertical coordinates of the backpack data points were saved in NAD83 and NAVD88 and exported as ASCII files. Person who carried out this activity:
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    Attn: Billy J. Reynolds
    Engineering Technician
    600 4th St. S
    St. Petersburg, FL
    USA

    727-502-8067 (voice)
    727-502-8181 (FAX)
    breynolds@usgs.gov
    Date: 2015 (process 4 of 6)
    Ground-Based Data Processing: Using ArcGIS, erroneous ground-based horizontal and vertical positions, such as those that occurred when the surveyor took off the backpack and was transported between shoals, were removed. Once all extraneous data points were removed, the remaining data were saved as an ASCII file. Person who carried out this activity:
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    Attn: Owen T. Brenner
    Geologist
    600 4th St. S
    St. Petersburg, FL
    USA

    727-502-8085 (voice)
    727-502-8182 (FAX)
    obrenner@usgs.gov
    Date: 2016 (process 5 of 6)
    Ground-Based Error Analysis: Using Matlab (2015b), ground-based GPS elevation errors were calculated by segmenting temporally sequential elevations into 10-minute segments and identifying crossings between segments where an elevation was within at least 0.25 m. The calculated RMS of those intersections is 8.5 cm. Elevation differences between the ground-based and single-beam data points indicated the ground-based elevations were 1.8 cm higher than elevations recorded using PWCs. Given the high degree of uncertainty arising from variations in the stride of the backpack surveyor over a subaqueous surface, the data were adjusted to the single-beam elevation at the crossings. The adjusted positions, elevation, and time of sampling were saved as an ASCII file. Person who carried out this activity:
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    Attn: Timothy R. Nelson
    Geologist
    600 4th St. S
    St. Petersburg, FL
    USA

    727-502-8098 (voice)
    727-502-8182 (FAX)
    trnelson@usgs.gov
    Data sources used in this process:
    • 201505_Ground_Based_XYZ.csv
    Date: 13-Oct-2020 (process 6 of 6)
    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?

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

  1. How well have the observations been checked?
    The accuracy of the data is determined during data collection. This dataset is derived from a single field survey using identical equipment, set-ups, and staff; therefore, the dataset is internally consistent. Methods are employed to maintain data collection consistency aboard the platform. During mobilization, each piece of equipment was isolated to obtain internal- and external-offset measurements with respect to the survey platform. All the critical measurements were recorded manually and then digitally entered into their respective programs. For ground-based measurements, elevation between the ground and antenna was measured for each surveyor in a walking stride and accounted for during postprocessing. For the GPS base stations, the Ashtech ProFlex 500 system has a long static horizontal accuracy of 0.3 centimeters (cm) and 0.6 cm vertical accuracy. For the rovers, the postprocessed kinematic horizontal instrument accuracy is 1 cm and vertical accuracy is 2 cm. The Echotrac CV100 Digital Hydrographic Echo Sounder has a vertical accuracy of 0.01 m +/- 0.1 percent depth.
  2. How accurate are the geographic locations?
    The GPS antenna and receiver acquisition configuration used at the reference station was duplicated on the survey backpack (rover). The base receiver and the rover receiver recorded their positions concurrently at 10Hz recording intervals throughout the survey. All processed measurements are referenced to the base-station coordinates. All static base station GPS sessions were submitted for processing to the National Oceanographic and Atmospheric Administration (NOAA) and National Geodetic Survey (NGS) On-Line Positioning User Service (OPUS) software. OPUS results provided an error measurement for each daily solution with a horizontal accuracy estimated as 0.5 cm root mean squared (RMS). Rover kinematic (rover) GPS data were processed with GrafNav v8.50 software by Novatel. The combined horizontal error for the rover was assumed to be, at most, half of the calculated vertical uncertainty.
  3. How accurate are the heights or depths?
    The GPS antenna and receiver acquisition configuration used at the reference station was duplicated on the mount. The base receiver and the rover receiver recorded the positions concurrently at 10 Hertz (Hz) recording intervals throughout the survey. All processed measurements are referenced to the base-station coordinates. OPUS results provided an error measurement for each daily solution. Applying these error measurements, the vertical accuracy of the base station was estimated to be 0.3 cm root mean squared (RMS). The kinematic (rover) trajectories were processed using GrafNav version 8.50 software by Novatel, Inc. An RMS of the elevation differences at backpack GPS trackline crossings were evaluated to determine vertical uncertainty. The combined vertical error from the base station coordinate solutions and the rover trajectories was 8.5 cm.
  4. Where are the gaps in the data? What is missing?
    This zip archive contains postprocessed horizontal position and vertical elevation point data (x,y,z) acquired with a backpack mounted GPS along the shoreface of Fire Island and the wilderness breach. This dataset is considered complete for the information presented, as described in the abstract section. Users are advised to read the online Data Series and the rest of the metadata record carefully for additional details.
  5. How consistent are the relationships among the observations, including topology?
    The U.S. Geological Survey St. Petersburg Coastal and Marine Science Center collected shallow water bathymetric data of the shoreface and the wilderness breach on Fire Island, New York, in May 2015.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints:
The U.S. Geological Survey requests that it be referenced as the originator of this dataset in any future products or research derived from these data.
Use_Constraints: These data should not be used for navigational purposes.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
    Attn: Timothy R. Nelson
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8098 (voice)
    727-502-8182 (FAX)
    trnelson@usgs.gov
  2. What's the catalog number I need to order this data set? 201505_Ground_Based_XYZ.csv
  3. What legal disclaimers am I supposed to read?
    This digital publication was prepared by an agency of the United States Government. Although these data were processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, nor shall the act of distribution imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 23-Sep-2021
Last Reviewed: 24-Aug-2016
Metadata author:
U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
Attn: Kathleen E. Wilson
Researcher
600 4th Street South
St. Petersburg, FL
USA

727-502-8099 (voice)
727-502-8182 (FAX)
kwilson@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/201505_Ground_Based_XYZ.faq.html>
Generated by mp version 2.9.50 on Thu Oct 14 09:26:12 2021